Printer Friendly Forum Posts - 02 trailblazer remote start tachless mode

Hi, I have an 2002 Trailblazer LTZ in which recently had an Code alarm CA-440tw remote start installed. It's just a bare remote start system with 2-way transmissions. I had this installed at Best Buy. The problem I'm noticing is that when I first try to remote start the vehicle in the morning after sitting a long time, it will crank over a few seconds and then stop, then it will try it again and fire right up. When warm, it fires right up on the first try. I asked the installer why this was happening, and they said they couldn't get the tach mode to work so they went with the tachless mode. It sounds lazy to me, so I asked them to adjust the crank time from the .8 sec to 1 or 1.5 to see if that helps. I was told they can't do this for fear it might damage the starter, but I'm sure the trailblazer's have the anti-grind feature or "intellistart" installed so it wouldn't make a difference if the truck tried to start a few tenth's of a second longer. My options for the cranking times are .8, 1, 1.5, and 2 seconds according the the installation manual. Would I be okay to increase this or is BB right that this will damage my starter?

Any help would be appreciated.

What I have learned about Trailblazer/Envoys- is that they need to be in Tach mode- if you want it to start everytime when it is cold out-- the Tachless mode looks at voltage rise when engine starts- But Trailblazers will keep the generator "offline" for up to 10 seconds when it gets about 15 degrees out- this is to assure the engine gets a chance to run properly before extra load is added-- but your Tach mode monitor thinks it does not start and shuts off the ignition- this is why I ALWAYS wire Trailblazers in the Tach monitor mode.....Had three do this to me before I figured it out.......

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Brcidd - Engineer That Does Remote Starter Installs on the side.

What I don't understand is how come on the second try it successfully starts and stays running? If it's still cold and the voltage is still held back, why is it not cutting the starter again instead of starting? It seems to me like it's the crank timing that is limiting the initial start. Best buy said that they couldn't get the tach mode to work, so that's why it's set up tachless. They swear that they've had to do this 100's and 100's of time and have had no problems. They mostly only install DEI, so I had to basically beg them to install the code alarm since no one else handles these here. I guess I should've bit the bullet and had bought one from a reputable dealer. I just would like to know if I can increase the crank time without hurting the starter in the trailblazer? I think if I can without harm, the remote starter should work just fine.

Let me start by saying that the tachometer connection is the way most installers feel is the only correct way to go. However, I am pretty sure that your truck has factory over crank protection. I know the fullsize GM trucks have it. To test this, start the truck with a key and hold the key in the start position for a split second longer than what it takes for the vehicle to start. If the starter continues to run with the key in the run position, make them hook up the tachometer. If the starter disengages as soon as the vehicle starts then just have them increase the crank time and it should be fine.

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Installer, IT support, and FFL. I need less hobbies.

Prove to them that no damage wil happen-- start it yourself- by holding the key to start mode well past the engine start-up-- your built-in antigrind feature will not allow damage- and neither will extending the crank time--

Also- try it yourself- first start in the morning- see if it takes 2-3 seconds of cranking to start with the key---then only a sec or so the second try-- just like the remote tries. This would conclude that your truck is hard to start- and has nothing to do with the remote starter- I have my old S-10 set up to Tach monitor- because it usually takes 5 -6 seconds of cranking to start it- using the remote or not----If I unplug the coil, the system cranks up to 15 seconds each trial- then quits- That is how I know Tach mode will always crank until start- (or till the 15 sec time-out)

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Brcidd - Engineer That Does Remote Starter Installs on the side.

Thank you so much for all your replies. The truck does have an anti-grind feature, so I will just have them increase the crank time from .8 to 1.5, and that should solve my problems.

Crank time is irrelevant on that car. Increasing it won't help.

Not only does the vehicle already come with anti-overcrank, it comes with anti-undercrank too.

You can check this. Turn the ignition on, move the key to the Start position for a moment, and release it right away. The starter will continue to crank until the engine starts.

Therefore, if using voltage sense, the crank time could be left on any one of those four possible settings, and it won't make a difference.

I agree with the others here. Trailblazers will work OK tachless sometimes.......just enough to let the installer think everything's fine and ship the car out.......the car almost always comes back.

The Trailblazer has an easily available tachometer wire inside right where the installer works to connect the rest of his wires.

However, the available wiring diagrams from the remote start manufuacturers are often riddled with timewasters, and they don't list this interior tach wire.

If you use the search feature on this forum, you should be able to find posts that describe where the tach wire is. Print that out and bring it to your installer.

Well, I tried to just flip the starter on from the ignition to see if it will continue to crank until started, but it didn't. I don't notice any anti-undercrank. I did change the crank time from .8 to 1.5, and that worked like a champ and it was a chilly night here last night.

I believe the anti-undercrank is only in the GM vehicles with no starter wire in the ignition harness. The one's that engage the starter when they see the accessory wire drop out.

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Installer, IT support, and FFL. I need less hobbies.

contact code alarm... explain whats goin on... they are pretty friendly... .make sure u tell them u don't have an authorized code alarm dealer near u!!!!!! they can tell u where to find somebody who can remedy your problem.... they may even be able to tell u how to get the tach mode to actually work too....

i work at a code alarm dealer.. i also installed code alarm too... last time i checked code alarm units 'DO NOT' attempt to recrank if tach is 'NOT' connected.... i will bet the farm that they probably have the tach goin to an injector instead of a true tach reference wire.... a lot of injectors will not give a full signal when cold.... there is your problem right there... i also know from personal experience this is the case because MY CAR does the exact same thing... i was too lazy to find the true tach so i just went to an injector.....lol

hope this helps...

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there can be only one.......

oh yeah... they didn't equip the envoy or trailblazer with under and over crank protection til around 05-06....... SO U DON'T HAVE THAT FEATURE ON YOUR CAR!!!

also... if thats the case... like i said earlier.. they went to an injector..... u could probably have em enable the tachless mode and set it to a 1 second crank and it will probably crank just about everytime... just remember... code alarm units DO NOT try again unless u disable the engine checking feature... this is a no-no because if the system malfunctions it may try to crank while the car is already running...

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there can be only one.......

I think that is incorrect. My 2002 trailblazer does have the over-crank protection, but not the under crank protection. I've tried it to verify this.

you're problem isn't an overcrank though... which means in theory it doesn't matter what they set the tachless pulse to... as long as it's long enough... it will be long enough.... because the car will cease cranking anyway after in has started.... well... sounds like u got some work to do..... imma leave u to it.......

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there can be only one.......

Thanks for the help skee-weezy.

I was successfull at getting it started on the first pop just by changing the crank time from .8sec to 1.5sec, and it stays running. I was confused at first by this, and by why it wasn't firing on the initial start attempt but firing on the second attempt. I felt like it just wasn't cranking it long enough after sitting all night.

yeah... dats happens sometimes... but u should be good to go for now.. your welcome......

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there can be only one.......

Well, everyone here is correct. It got pretty cold last night, a little colder than they past few days, and the truck went back to the normal behavior of cranking, stopping, cranking, stopping, cranking, and then finally firing up. This time it took 3 tries, so it doesn't matter on the crank time just like everyone said here. I think it worked yesterday because it the air was just a little warmer than 32 degrees when I tried it, but this morning at 27 degrees, no go until the 3rd crank. I'm going to bring back the truck to best buy and have them get this working off the tach instead of the tachless they have set up. I bet they didn't even run a wire to the tach, otherwise I could probably figure it out myself to reprogram the tach. The programming feature for the remote start is pretty easy to understand.

Man I wish I would have read this post prior to during an 03 trailblazer last week. Chris Luongo can you share the info on the location of the tach wire? I just had this vehicle return because of a battery issue.

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MEH66
"Car Performance and Mobile Electronic Enthusiats"

I believe it was in pin 49 located in the pcm. Well, that's where I followed it to. It's working great since I learned the tach setting.

tach location on all year trailblazer and envoy

white wire at left plug in cluster. Works great, easy to get to and reliable. Over 1000 trailblazers on the road with no failures to crank. If you pull the dash bezel off (envoys are super easy because the radio bezel is seperate). You do not need to remove the cluster, the harness is right there. There is only one white wire and it is the same on all trim levels v6/v8/ and ss

edit: I like this because I like to keep tach wire inside the car

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