Printer Friendly Forum Posts - viper 5704 comm issue

Hi,

I have installed 2 5901's in my vehicles with no issues what so ever. I recently purchased a 5704 to install into a 65 Shelby Replica I am building.

I have everything wired properly to my knowledge for the system to function. The issue I have is, when I remote the car (EFI 302), the car will start and runs fine, but both the one way and two remotes will not communicate with the brain. I get the dread transmitting waves on the remote followed by the failure buzz.

Basically I could arm my car, remote start my car, open the door (no triggers), key in, press brake and drive off with most likely the alarm sounding (cant disarm). Remote does not receive signal until after car is off. It acts like the transmitter in the brain shuts off while the remote start is on.

This car has no door sensors or anything normal cars will have for secondary wiring hook ups.

I have wiring the remote start as:
Red - 12V+ constant at switch
Orange - 12V+ accessory at switch
Pink - Ignition 12+V switched
GREEN/ Purple = correct sides of starter feed
RED / Black = 12+ for starter feed.

Besides those connections, all I have hooked up are:

12+V and Ground
Siren output
Neutral safety grounded
tach input (set to tach sensing not virtual)
brake shutdown

I swapped out the 5704 brain with a 5901 brain and had the same condition.

This leads me to believe it is a programming issue or wiring issue.

Does anyone know what may cause this condition?

What happens if you start the car with the key? Can you activate "pit stop" mode? My initial thought would be the ignition system of the car interfering with the antenna.

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Kevin Pierson

check the settings on the keypad. there are settings on them for how it transmits and receives and how often it updates.

where is the antenna located? i know that sometimes it can have interference from other electrical signals.

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I cannot activate pit stop mode, or arm/disarm while remote start is activated. I can put key in ignition and hit brake pedal and it will stay running.

No issues with starting with key. What I can check is to see if there is any comm with remote while key started. I dont think there should be though, correct?

I thought there may be interference as well, so i stretched out the antenna cable and mounted it 5 feet about the car. Still no luck.

Pit Stop mode is when you start the car with the key, then remote start the car, then remove the key from the car.

The fact that the brake pedal doesn't shut down the remote start concerns me a bit. It almost sounds like the brain is freezing up after remote starting. Have you verified you are getting 12vdc on the brake input wire when you step on the brake?

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Kevin Pierson

Sorry if my post was not clear, the brake pedal does shutdown the remote start. this is the only way I can turn it off since the remote will not comm.

Also, with the pitstop mode, I need to verify, but i do not think the pitstop mode will work when the vehicle is running, likely from the comm issue.

I can however cancel the remote start signal during the initial ignition turn, before the engine cranks with the remote.

I have the same symptoms with both 5704 and 5901 brain, wired identically.

I meant to say that I can take over correctly from a remote start (key in, step on brake), even though my remote does not receive the remote start shutdown notification until after the car is off.

have you checked the settings in the function menu of the keypad? faulty wiring wont cause the keypad to lose communication only during remote start.

you might also try deleting all keypads from the brain and re-syncing everything from scratch.

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I disconnected power from the unit, repaired the 2 way remote and set it to auto trans mode. It remote starts fine, but still the brain will not receive a command from either 1way or 2 way remotes. During a full trigger alarm, the remote will turn it off FYI.

Thanks,
Tyler

soundnsecurity wrote:

have you checked the settings in the function menu of the keypad?

my brain is starting to hurt thinking about what this might be. also did you do anything with the WHITE/ blue activation wire?

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Yes, I set it to Sec and RS. The power save is ON. What specific settings are you referring to?

Thanks for the help.

maybe turn power save off. i dont know what setting exactly, i just know that it has settings that control the transmitter functions. there are also different permissions you can set so that other keypads dont have full control because these remotes can be set to multiple alarms. what is "sec"? does that mean you have it set to secondary? i added to my last post but you beat me to it. i wanted to ask if you hooked the WHITE/ blue activation wire to anything?

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Sec was short for security, IE remote is in security and RS mode.

WHITE/ blue RS timermode wire is not hooked up. If I ground while RS is active, it will kill the engine. I can start RS with wire grounded and no problems. (except of course lack of communication with remote)....

I posted on another forum and someone thought I was losing either 12V+ or ground when RS activated, hence resetting brain. I checked and ground lost continuity when RS happened. Ran direct wire to battery Negative still have same issues....I checked voltage at brain harnesses during RS startup, all looked consistent.

remote i believe needs to be in remote start mode, i dont think it can be in both security AND remote start mode. if it is in security mode then i believe the keypads wont work while it sees an ignition source because they dont want you locking the doors while the key is in ignition. power save being on means that it will only communicate and respond when you push a button. it wont update itself automatically, this is why it only tells you about the remote start shutdown when you kill the car and not when you actually deactivate the remote start.

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I have tried it both ways, and still same outcome. I do not know what else it could be. Is there any wire that needs a signal while the engine is running? I am using hard tach hookup

man, i have no idea. it has to be a setting somewhere. i have a 5901 on my own truck so im pretty familiar with it even though i dont install a lot of viper alarms overall. mine is a few years old though so yours might have other settings that im not aware of or the setting work differently than what im used to. as far as i know, there is no wire that has anything to do with the transmitter.

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Yes, its very frustrating. I am about to pull the 5901 brain out of my truck that everything functions perfectly, just to test it with my setup. Will the brain retain the current settings if it loses power for a few minutes? Or do I need to hook up temp 12V+ power?

One thing that might be worthwhile to check is the connections for the antenna; the other day I was testing something out with my 5704 and I didn't feel like pushing the connector into the antenna end all the way in because it is hard to disconnect and I experienced this same exact issue. The alarm brain receives the remote's signal just fine, but it doesn't transmit back to the remote to confirm the operation.

Might be worthwhile to take a look just in case that's the only problem, good luck!

Did you ever try the Pit Stop mode? I am still curious if the brain loses communications when the car is started with the key, or only when remote started.

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Kevin Pierson

KPierson wrote:

Did you ever try the Pit Stop mode? I am still curious if the brain loses communications when the car is started with the key, or only when remote started.

So here is a brain buster for yall. FYI I did reseat the antenna cable ends, no change but worth while check.

Two scenarios:

A) I turn the ignition on with key(do not start), click remote start button. the transmit ")))" waves flash on the remote and disappear. This is the behavior on my truck which is normal.

B) I key start car, click remote start, the remote then goes through the ")))" then the "((((" then finally the "X" with buzz for transmit failure....so no Pit stop mode...

I have the tach hardwired from the ECC, could this cause an issue? The only differences between A and B listed above, is there is a 12V signal sent through the starter wires on B and there is a voltage signal to the tach wire.

as far as i know, alarms wont lose settings if they are powered down, but you will probably have to reprogram the tach to work with a new car.

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hey, have you tried switching out the antenna from one alarm to another? you say you switched the brains out but maybe its a fault in the actual antenna which is why you got the same response with both brains.

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I would disconnect the tach wire and see if anything changes. That is the only thing that should be "changing" between running and not running. Where did you get the tach wire from? Where is the brain mounted? I would also make sure there is ignition wires any where near the brain or any of the antenna wiring.

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Kevin Pierson

Today I will try the following and report back:

Swap Antenna from known working system.
Disconnect tach wire (wire from 93 mustang ECC)(will try virtual or voltage)
Move brain and antenna away from any ignition wires.

Currently the brain is sitting loose between firewall and dash, at least 6-8 inches from ignition switch.

So I swapped the antenna, no change in behavior.

I also disconnected the tach wire, set to virtual tach. System learned it no problem. Still same issue with no comm while remote start is active...

are you using any kind of bypass module? if so, what model is it and how is it wired into the system? where is it grounded to the car?

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nope, no bypass module. This setup is the simple of simple. I will take a photo or two and post

Just skimming through this thread so I apologize if this has been asked or answered already, but Since this is an engine swap into an older car by the sounds of it...Is the charging system regulated? What is the output voltage of the alternator at idle (higher rpm's don't matter as a remote start only functions when the engine is idling)? Though an unregulated voltage system COULD damage devices like this while they are inactive. Just something to think about. Hope you get this figured out!

It is usually the simplest of problems that stump the true experts. posted_image

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To master and control electricity is perfection. *evil laugh*

tylerwayne wrote:

nope, no bypass module. This setup is the simple of simple. I will take a photo or two and post

i figured you wouldnt be using a bypass but i had to ask because sometimes bypass modules have more control over the remote starter than you would think and its possible that the bypass could be interfering with the antenna port.

so now we have basically ruled out everything i can think of that deals with the remote starter being the problem. it has to be something to do with how the car is wired and how the remote starter is wired to the car.

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Are you using an aftermarket ignition system such as a MSD? If so remove it and just use the stock TFI distributor. Might be getting some RF interference with a MSD ignition.

HTH,

Pete

I had a simular problem with a 5101 with a antenna and remote upgrade to LC3 two way and it would lock and unlock and remote start but no 2 way back of any kind. Unit bench tested fine with a different harness. So I moved the ground to a better location and now it works fine. Dei units are funny about having good grounds.

Try running a temp ground from the viper unit to the battery and see if it clears up.

lurch228 wrote:

Try running a temp ground from the viper unit to the battery and see if it clears up.

he said he already tried running a ground straight to the battery.

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I must have missed that part.

When remote started DMM the sources for voltage drop. Do you have more than one 12v constant at the switch if you do try seperating the H3 Red and RED / Black to seperate constant sources. To see if you are pulling to much power from the one circuit for the viper to function properly when remote started. It sure sounds like the brain is starving for power and the 2-way systems need good power to work properly. Try going to the battery with both the H1 power and ground, trying to eliminate one more possible cause. Other wise as a last resort you can try testing with a DMM all sources looking for any kind of feed back or bleed to ground.

Did you ever verify if the Pit Stop feature works? I'm still not clear on when it loses communication and when it doesn't.

Does the two way remote communicate when the car is started and running with the key?

Does the two way remote work if the key is in the "ON" position but the motor isn't running?

If you lose communication any time the car is running I would disconnect EVERY wire but power and ground and retest. If you don't lose communication when the car is running with the key then I would disconnect every remote start related wiring (ignition, accessory, starter, etc) and retest.

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Kevin Pierson

allnpt0 wrote:

Are you using an aftermarket ignition system such as a MSD? If so remove it and just use the stock TFI distributor. Might be getting some RF interference with a MSD ignition.

HTH,

Pete

I am using an MSD 6AL. I will disable and try the other things people have said and report back.

Thanks guys.

Keep us updated as I think we would all like to know the cause.

i figured there might be some sort of high powered ignition system installed and the thought did cross my mind that it might be causing some interference but i dont know anything about them so i didnt say anything, hopefully that is the cause.

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If the MSD is causing the issue it will affect the communication any time the engine is running.

KPierson wrote:

Did you ever verify if the Pit Stop feature works? I'm still not clear on when it loses communication and when it doesn't.

Does the two way remote communicate when the car is started and running with the key?

Does the two way remote work if the key is in the "ON" position but the motor isn't running?

If you lose communication any time the car is running I would disconnect EVERY wire but power and ground and retest. If you don't lose communication when the car is running with the key then I would disconnect every remote start related wiring (ignition, accessory, starter, etc) and retest.

I disconnected the MSD 6AL and am running the stock ignition. No change in behavior. disconnected ground and positive wires to MSD.

With the Key ON and engine OFF: I can click the lock/unlock and the remote does the quick flash of the transmit and disappears. This is the correct behavior. If I click remtoe start, the remote says remote start on, but engine does not crank.

Pit stop mode will not work. I start engine with key, click the RS button, but I get the XX on the remote.

I doe have the RED / black and Red wire soldered together, running to the battery. I will go through again wire by wire with my multimeter to verify all voltages during start up.

posted_image

So you have verified that it is simply the car running that kills the communication - that's an important accomplishment.

Where is the antenna wire ran? You should avoid bunching the antenna wire up on itself.

Disconnect all sensors and wire harnesses that are not being used. I would disconnect everything but power, ground, and the antenna. Perform the test again with the car running to see if you can communicate with the brain.

What is battery voltage when the vehicle is running?

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Kevin Pierson

One you have rechecked all the H3 wires to vehicle and charging system is putting out good voltage(13v+) while running, Check for groung issues from motor to chassis, if you have poor motor grounds it can cause a imbalance in the electrical flow, verify good alternator ground. If nothing turns up then the next suspect would have to be the factory wiring has a issue. Can you try the remote starter with out the ignition switch shown in the pic to see if there is any change. Depending on the factory wiring harness you are using is it pulling all is current through the same wires that the remote start is to power everything.

One thought occurred to me, your first post said you connected H3/9 RED / black, you didn't mention H3/2 RED / white.
From your photo it looks the other way round.
Try connecting both AND take ALL of your power and ground feeds directly to the battery.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Yeah, Howie I read the first post multiple times and he isn't using the Flex relay at all, so no need for the H3/2 RED / White, but the other H3 direct to the battery I assumed he had already done by his previous post with the picture.

tylerwayne wrote:

I doe have the RED / black and Red wire soldered together, running to the battery. I will go through again wire by wire with my multimeter to verify all voltages during start up.

I can't figure out what would be the cause of this, but I'm leaning towards some kind of issue between the engine harness and the vehicle harness not providing good power or ground if none of the other things mentioned to try don't solve the problem.

OK but that was the only thing that appeared wrong.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Ok, I will run the necessary 12V+ constant power wires to the battery directly as well as the ground.

The antenna wire is stretched out and temporarily mounted on the rear bulkhead of the car.

As for testing comm while engine is running (with ignition input/output hooked up) , the only comm it should be able to normally do is pit stop mode, and maybe temp sensor? What other comm features can I test while engine is running?

Or are you saying to just hook up power and ground without a run/ignition input so the brain does not know the vehicle is running so I can test if the running vehicle causes RF interference? Good idea...

I am out of town this week, but will hopefully be able to post an update Friday.

tylerwayne wrote:

What other comm features can I test while engine is running?

The lock/unlock, Aux(Trunk), Panic, Temp, Status should all still work reguardless of it being started by key cylinder or remote start.

tylerwayne wrote:

Or are you saying to just hook up power and ground without a run/ignition input so the brain does not know the vehicle is running so I can test if the running vehicle causes RF interference?

Yes, that would be another thing to eliminate for the comm. problem.
At this point start with the most basic hook up power and ground direct to battery to viper with vehicle running and test comm. if it dosen't work then it's a vehicle interference issue. If it does comm. then add a wire and test again with vehicle running until you find a wire connection that is the cause. Then you can trouble shoot it.
Start with the H1 red, black the add in this order,(neutral saftey to ground, H3 RED, PINK, RED / BLACK, VIOLET, Tach). Testing with each connection the comm. with remote start then key switch vehicle running. The viper will enter remote start mode as long as it is set to Automatic trans, the neutral saftey wire is grounded, and the neutral saftey switch is pluged in and on, but will time out if no tach is seen after 3 start cycle tries. Once you got the 4 H3 wires (RED,PINK,RED / BLACK,VIOLET) needed hooked up for engine to run with remote start, test comm. with viper again while remote started. If it is comm. fine then add the H3 ORANGE and so on. Testing each step of the way until the viper stops comm. again.

Guys,

Interesting finds. SoI hooked up only the POWER, Ground and Antenna directly to the trunk mounted battery. Works for lock/unlock while vehicle is OFF. Engine running, no comm situation with remote. I connected and disconnected altenator and no comm either way.

Second scenario. I took a second car battery, not connected to the carat all. Placed in trunk area and connected alarm power and ground only, again it is not wired to car. Turned car on and I am getting comm during engine is running.

That test makes me disprove that there is an RF interference from engine. However there seems to be a wiring issue from the car to the battery? What do yall think? I am going to fully charge the car's battery and retest to confirm.

Check for inverted wires in the car, and verify all grounds for the engine harness, and the vehicle harness. Also verify proper function of Ignition switch, and that it's not resting any (+)outputs at ground when off.

lurch228 wrote:

Check for inverted wires in the car, and verify all grounds for the engine harness, and the vehicle harness. Also verify proper function of Ignition switch, and that it's not resting any (+)outputs at ground when off.

The 12V+ at ignition switch is 0 OHMS to ground
the Ignition and ACC posts both have about 20 OHMS to ground with no power supplied to them.

The starter feed to start solenoid has about 5 OHMS to ground when off.

Are those measurments in the key off position with the battery connected?

Also check for key off voltage on the outputs from the key switch.

Based on the Ohms on the Ingition and ACC posts would lead me to believe one or both has a ground issue. AKA common ground.

What is the battery voltage when the car is running?

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Kevin Pierson

KPierson wrote:

What is the battery voltage when the car is running?

Yes, that is with key off and battery connected.
This is Factory Five MK4 roadster (65 cobra. I am running a Ron Francis harness + EFI harness for engine.

The vehicle is charging properly and I have tested comm with and without alternator connected during engine ON.

Thanks guys

I am going to start by pulling fuses and retesting continuity to see if I can narrow down the leak.

The higher resistence on the ingnition and ACC would be a poor connection on the (+) or bad ground. As you increase flow or load the resistence will go up. Try checking the resistence under load on the circuits. But I would start with the ground side of the Ron Francis harness. As the higher ohms on both circuits has to be a common issue.

I don't think you have an issue with your ignition wiring. If you connected the alarm directly to the battery like you stated you did and the system didn't work while the car was running the ignition switch would be ruled out. I'm not sure how the +12 is measuring 0 ohms to ground, but I wouldn't be surprised to see the ACC or IGN within 20 ohms to ground with the key off - these wires typically rest at ground when the key is off.

At this point I would expect a voltage level issue (ie too much voltage or too little voltage while the car is running) or a very noisy DC ground level that may be impossible to diagnose without an oscilloscope. The ignition system would still be my #1 suspect for noise as the high voltage and high frequency can create all sorts of noise issues. It may be beneficial to put a very large cap (like a 1F) right at the alarm and see if anything changes. This will level voltage and can smooth out any ripple. However, it won't fix voltage level issues.

What is the battery voltage while the car is running?

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Kevin Pierson

KPierson wrote:

I don't think you have an issue with your ignition wiring. If you connected the alarm directly to the battery like you stated you did and the system didn't work while the car was running the ignition switch would be ruled out. I'm not sure how the +12 is measuring 0 ohms to ground, but I wouldn't be surprised to see the ACC or IGN within 20 ohms to ground with the key off - these wires typically rest at ground when the key is off.

At this point I would expect a voltage level issue (ie too much voltage or too little voltage while the car is running) or a very noisy DC ground level that may be impossible to diagnose without an oscilloscope. The ignition system would still be my #1 suspect for noise as the high voltage and high frequency can create all sorts of noise issues. It may be beneficial to put a very large cap (like a 1F) right at the alarm and see if anything changes. This will level voltage and can smooth out any ripple. However, it won't fix voltage level issues.

What is the battery voltage while the car is running?

He has tried 2 different ignitions systems and the same issue.
He has checked the voltage when running and it tested good.
The number 1 cause of noisy grounds is a poor connection to ground.
If you have a poor connection on ground you will loose amps/current not volts under load, due to resistence which can cause a noisy dc system. Can even cause noise in radio reception, like whine.
20 ohms no load will multiply as load increases on a poor connection.
I have never seen a Ignition or ACC have that high of resistence and work properly. They usually have 3 to 4 ohms max on feed circuit wires of this kind.

Poor RFI shielding on the ignition/injection system?
Bad alternator ground?
Bad, poor or lack of engine to body work to battery grounds?

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

lurch228 wrote:

KPierson wrote:

I don't think you have an issue with your ignition wiring. If you connected the alarm directly to the battery like you stated you did and the system didn't work while the car was running the ignition switch would be ruled out. I'm not sure how the +12 is measuring 0 ohms to ground, but I wouldn't be surprised to see the ACC or IGN within 20 ohms to ground with the key off - these wires typically rest at ground when the key is off.

At this point I would expect a voltage level issue (ie too much voltage or too little voltage while the car is running) or a very noisy DC ground level that may be impossible to diagnose without an oscilloscope. The ignition system would still be my #1 suspect for noise as the high voltage and high frequency can create all sorts of noise issues. It may be beneficial to put a very large cap (like a 1F) right at the alarm and see if anything changes. This will level voltage and can smooth out any ripple. However, it won't fix voltage level issues.

What is the battery voltage while the car is running?

He has tried 2 different ignitions systems and the same issue.
He has checked the voltage when running and it tested good.
The number 1 cause of noisy grounds is a poor connection to ground.
If you have a poor connection on ground you will loose amps/current not volts under load, due to resistence which can cause a noisy dc system. Can even cause noise in radio reception, like whine.
20 ohms no load will multiply as load increases on a poor connection.
I have never seen a Ignition or ACC have that high of resistence and work properly. They usually have 3 to 4 ohms max on feed circuit wires of this kind.

But if he connected the system directly to the battery that would rule out a bad in car ground. If the poor ground was a chassis ground and he chassis grounded the system I could see there being a problem. But, if he connected the system directly to the battery a poor chassis ground shouldn't affect anything.

It's definitely an interesting case and something I've never seen or heard of before.

Also, he has not posted what the voltage is at running, just that he checked it. I am curious if the voltage is right at 14.4vdc or higher or lower.

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Kevin Pierson

KPierson wrote:

lurch228 wrote:

KPierson wrote:

I don't think you have an issue with your ignition wiring. If you connected the alarm directly to the battery like you stated you did and the system didn't work while the car was running the ignition switch would be ruled out. I'm not sure how the +12 is measuring 0 ohms to ground, but I wouldn't be surprised to see the ACC or IGN within 20 ohms to ground with the key off - these wires typically rest at ground when the key is off.

At this point I would expect a voltage level issue (ie too much voltage or too little voltage while the car is running) or a very noisy DC ground level that may be impossible to diagnose without an oscilloscope. The ignition system would still be my #1 suspect for noise as the high voltage and high frequency can create all sorts of noise issues. It may be beneficial to put a very large cap (like a 1F) right at the alarm and see if anything changes. This will level voltage and can smooth out any ripple. However, it won't fix voltage level issues.

What is the battery voltage while the car is running?

He has tried 2 different ignitions systems and the same issue.
He has checked the voltage when running and it tested good.
The number 1 cause of noisy grounds is a poor connection to ground.
If you have a poor connection on ground you will loose amps/current not volts under load, due to resistence which can cause a noisy dc system. Can even cause noise in radio reception, like whine.
20 ohms no load will multiply as load increases on a poor connection.
I have never seen a Ignition or ACC have that high of resistence and work properly. They usually have 3 to 4 ohms max on feed circuit wires of this kind.

But if he connected the system directly to the battery that would rule out a bad in car ground. If the poor ground was a chassis ground and he chassis grounded the system I could see there being a problem. But, if he connected the system directly to the battery a poor chassis ground shouldn't affect anything.

It's definitely an interesting case and something I've never seen or heard of before.

Also, he has not posted what the voltage is at running, just that he checked it. I am curious if the voltage is right at 14.4vdc or higher or lower.

Guys thanks for yalls help. Though I know it is an interesting case, that may not be my first choice of words for this road block.

I will put the DMM on the battery while running and off and post results.

I know the gauge was reading right around 14, but the precision of that is purely for go/no go on charging.

The ground for the alternator is created by the mounting bolt, there is no cable or strap to engine.

I will post some pictures today of the overall set up so everyone can visualize a little better what I am working with.

KPierson wrote:

But if he connected the system directly to the battery that would rule out a bad in car ground. If the poor ground was a chassis ground and he chassis grounded the system I could see there being a problem. But, if he connected the system directly to the battery a poor chassis ground shouldn't affect anything.

This would be completely true if the battery wasn't still connected to the rest of the car's electrical system where the problem of intereference is coming from. That's why when he tested the comm. with a spare battery connected to just the viper it worked fine with the motor running. Which leads back to a lack of ground, and he now says that he has no straps to the engine on a EFI setup.

lurch228 wrote:

KPierson wrote:

But if he connected the system directly to the battery that would rule out a bad in car ground. If the poor ground was a chassis ground and he chassis grounded the system I could see there being a problem. But, if he connected the system directly to the battery a poor chassis ground shouldn't affect anything.

This would be completely true if the battery wasn't still connected to the rest of the car's electrical system where the problem of intereference is coming from. That's why when he tested the comm. with a spare battery connected to just the viper it worked fine with the motor running. Which leads back to a lack of ground, and he now says that he has no straps to the engine on a EFI setup.

To clarify, The alternator ground is created from the mounting bolt, not a strap.

I do have the following grounds:

Battery to frame (trunk mounted)
Engine to frame
Main harness to frame
EFI harness to engine (intake)

I will test these ground for resistance later today.

I'm still betting on the injector wiring.
Euro GMs (Vauxhall and Opel) had years of problems with the injector and coil pack looms. And that was OEM, even though the Bosch based system was identical to that used by VW.
In fact on both Vauxhall Astra (Saturn Astra) and Golf Mk IV there have been idling problems with R/S tach wires being connected to an injector wire even though the R/S units are supposedly high impedance buffered.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

howie ll wrote:

I'm still betting on the injector wiring.
Euro GMs (Vauxhall and Opel) had years of problems with the injector and coil pack looms. And that was OEM, even though the Bosch based system was identical to that used by VW.
In fact on both Vauxhall Astra (Saturn Astra) and Golf Mk IV there have been idling problems with R/S tach wires being connected to an injector wire even though the R/S units are supposedly high impedance buffered.

So if this was true, what would be the remedy? Could I use a diode to isolate the circuit?

I have a relay pack to supply the EFI harness and I am going to narrow down what each one is supplying and where the continuity to ground is coming from.

OK here is an update:

The picture below shows the relay pack with the ignition switch feeding the 85 pin, orange wire. the wires on the right are the output wires(87). Two of the 87 wires have continuity to ground, to the O2 sensors and fuel pump. I disconnected the O2 sensor and bypassed the relay for the fuel pump. Supplied power straight from battery, still no comm.

posted_image

The continuity to ground from the IGN post while IGN off is coming form the relay pack. 85 is ground and 86 is signal from IGN post, about 88Ohms X 3 in series gets you to the 29~ Ohms I am getting at the IGN switch.

At the battery I am getting 14.20vdc while running.

All grounds, frame to battery, frame to engine, EFI harness to engine, main harness to frame are <0.5ohms

I do not think the continuity to ground from IGN post is causing the no comm issue. If that were the case, then a simple dash light wired from the IGN post to ground would cause a no comm issue while running.

Photos:
posted_image

Additional information, as my mind was trying to determine a way to have the car running without the EFI harness as part of the circuit...

Eureka...So the EFI Ron Morris harness has a direct connect to the battery post, along with the normal lead clamp 2 gauge battery wire.

I started the car, disconnected the main battery wire (2 gauge), no comm. disconnected the main battery wire and EFI harness.....I get comm with remote.

AKA I was running the car with the alternator provides the current and battery outside the circuit. However that may show that the EFI harness is having an affect. I cannot try to test the other way though (main battery cable connected and EFI disconnected since the EFI harness pulls power from it). The only way to eliminated the main harness from error is to run the EFI harness on separate battery and try to comm while engine running and main harness hooked up to car battery.

Right so I was on the right track with the EFI, any way to physically separate the battery leads from the rest?

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

I would also like to point out that this isn't a grounding issue, it's an interference issue, suppression interference, a lost art for installers with the advent of Phillips IAC circuitry in the mid 70s for suppressing noise on FM circuits.
Think shielding rather than grounding.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

howie ll wrote:

I would also like to point out that this isn't a grounding issue, it's an interference issue, suppression interference, a lost art for installers with the advent of Phillips IAC circuitry in the mid 70s for suppressing noise on FM circuits.
Think shielding rather than grounding.

Would the interference effect the circuit? I tested the comm with the viper connected directly to a spare battery outside vehicle circuit. comm worked fine while vehicle was running.

That points to inductance rather than radiation.
Lotus Europa, the Europa bit being the engine out of a Renault 16, mid 70s. Fiberglass body.

Aluminium foil glued to underside of hood.
Grounding bonds to hood to engine block to bodywork.
3mfd. cap on alternator.
1mfd. cap on coil.
Exhaust pipe bonded back to engine.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

howie ll wrote:

That points to inductance rather than radiation.
Lotus Europa, the Europa bit being the engine out of a Renault 16, mid 70s. Fiberglass body.

Aluminium foil glued to underside of hood.
Grounding bonds to hood to engine block to bodywork.
3mfd. cap on alternator.
1mfd. cap on coil.
Exhaust pipe bonded back to engine.

Well my body will be fiberglass. The foil is a no-go on the underside of the hood. It will be body color.

Is this the only solution?

My question is, how can you have a remote start function on a foxbody mustang (the type of engine and computer I am running) and not work on this?

If we are going in the right direction and remember this is only an experienced based hunch, the average steel bodied car is basically a series of Faraday cages.
Some how you need to isolate the ignition electronics.
I'm not sure how you would go about this because neither you nor I have the R&D resources of the motor manufacturers.
In the late 70s I owned a Ford Capri and a Fiesta.
I fitted a Bosch capacitive discharge ignition system to the Capri, it was a radio interference nightmare.
I installed an infra-red point system unit on the Fiesta and it was wonderful!

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

You can try this to see if using capicators across the positive and negitive wires for the viper has any positive effect.

The viper would be substituted for the motor in the diagrams.
noise isolation

Thanks Lurch, I think figure 5 might be relevant.
Those cap. values are far lower than we used back in the day.
1 mfd. on the coil and 3 mfd. on the alternator.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

lurch228 wrote:

You can try this to see if using capicators across the positive and negitive wires for the viper has any positive effect.

The viper would be substituted for the motor in the diagrams.
noise isolation

Are we talking just little radioshack capacitors? Run one in parallel between ground and power to viper?

Run one in parallel of coil leads?

For the alternator, its not a one wire style, It is a 3G ford style.

tylerwayne wrote:

Are we talking just little radioshack capacitors?

YES

tylerwayne wrote:

Run one in parallel between ground and power to viper?

YES first

tylerwayne wrote:

Run one in parallel of coil leads?

YES second

Start with the simplest solution and work your way out and up to the others.

lurch228 wrote:

tylerwayne wrote:

Are we talking just little radioshack capacitors?

YES
tylerwayne wrote:

Run one in parallel between ground and power to viper?

YES first
tylerwayne wrote:

Run one in parallel of coil leads?

YES second

Start with the simplest solution and work your way out and up to the others.

OK I will try this. Excuse my ignorance but can you specify what kind of cap I should use?

Disc / electrolytic? 3mF? I have seen 16V, will this work? Will they require a charge similar to car audio larger caps?

A part number would be excellent, or specs.

Thanks for yalls help.

Tyler

Follow the motor 1 diagram and start with the 0.1uf capacitor, as it applies to the viper. Since the problem is with the viper, and we need to try and isolate it from the noise.

Single Capacitor Filtering

Figure 1. A simple one-capacitor noise filter

The simplest filter involves adding a capacitor across the motor terminals as shown in figure 1.

Since a capacitor will conduct only currents that are changing at a high frequency, a single capacitor (typically 0.1µF) wired across the motor terminals (as shown in Figure 1) will act as a short circuit for high-frequency electrical noise, while not affecting the DC current to the motor at all. This reduces conduction of noise along the motor wiring.

lurch228 wrote:

Follow the motor 1 diagram and start with the 0.1uf capacitor, as it applies to the viper. Since the problem is with the viper, and we need to try and isolate it from the noise.

Single Capacitor Filtering

Figure 1. A simple one-capacitor noise filter

The simplest filter involves adding a capacitor across the motor terminals as shown in figure 1.

First tried a 1uF cap in the viper, no comm, added on to coil in parallel and car doesnt start.

Is there a way I can run the alarm off of a small 12V battery and isolate it from the main harness except for the ability to charge? Maybe put an addition alternator output on a switch to the secondary battery?
Since a capacitor will conduct only currents that are changing at a high frequency, a single capacitor (typically 0.1µF) wired across the motor terminals (as shown in Figure 1) will act as a short circuit for high-frequency electrical noise, while not affecting the DC current to the motor at all. This reduces conduction of noise along the motor wiring.