compustar 2wssr tach signal

Hello,

Heres the deal, I recently added a piggy back ECU to my car and now turbo timer mode does not work, the car just shuts off never getting into reservation mode. Before it worked fine. The alarm itself works great otherwise.

So, I did some testing, I removed the piggy back and ran the car plugged up to the OEM ECU it worked fine. I plug back in the piggy back pressed the little black button on the back of the brain "Tach Learning Switch" and it chrips 3 times meaning theres no tach signal SO thats my problem. Some how the tach signal isn't reading to the brain when the piggy back ECU is plugged in.

Now is there ANY way to get around this just to make the turbo timer work? I believe the tach signal is tapped into the engine where the coil pack is. If I can find a wiring diagram to my piggy back's wiring from the plug and find where the tach signal is there maybe I can tap it.

Any Ideas what I should do?

Car info?? year/make/model

If you're snagging the tach signal from the ECM, you may be able to tag the signal from a coil pack or injector (or alternator if you have one)

You indicated that you have the "r" version of the 2wss .. does the remote start work with the piggy back ecu?  If so, it's still getting a tach signal, otherwise it wouldn't start appropriately.

this is for your tach signal

peterubers wrote:

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Car info?? year/make/model

If you're snagging the tach signal from the ECM, you may be able to tag the signal from a coil pack or injector (or alternator if you have one)

You indicated that you have the "r" version of the 2wss .. does the remote start work with the piggy back ecu?  If so, it's still getting a tach signal, otherwise it wouldn't start appropriately.

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Negative, the remote start does not work with the piggy back ecu plugged in. If I unplug it everything works fine.

so -- i would do the following (i think you already get the idea)

1) plug the piggy back ECU in

2) connect the tach wire off the compustar to the wire at on of the six coil packs or injectors

3) re-learn the tach signal on the compustar

4) attempt remote start, then attempt entering reservation mode.

So you connected the tach wire from the compustar to the coil pack in the engine bay?  Did you meter the wire you tapped at the coil pack (or did you use the injector)? 

Did you try a different wire (i.e. if you used a coil pack wire before, try an injector wire)?

You could also just VMM the wire before doing any changing of wires and see what's going on there.  Make sure you see an alternating voltage less than 1-3 vdc.

maximumsportz wrote:

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I'll try a different wire but that wire works when the stock ECU is plugged in so I dont know if another wire would make a  difference....

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...but that wire does not work with the piggy back ecu ...

what is the specific purpose of that piggyback ecu -- does it change fuel/o2 ratios, shift points, throttle response?

peterubers wrote:

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maximumsportz wrote:

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I'll try a different wire but that wire works when the stock ECU is plugged in so I dont know if another wire would make a  difference....

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...but that wire does not work with the piggy back ecu ...

what is the specific purpose of that piggyback ecu -- does it change fuel/o2 ratios, shift points, throttle response?

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yea its kinda semi stand alone ecu that still uses the stock ecu for some things.

that's why i think the wire you are using may not work now -- y'know .. i figured it changes the fuel mixture or something with spark plug timing -- that may be why the compustar does not recognize the signal coming from the tach wire with the piggy back ecu installed.

You MAY only have to reset the compustar brain entirely and RE-LEARN the tach signal without messing with the tach wire connection.  I would try this first as this will likely resolve your problem.  If that does not work, then:

1) reset the compustar

2) install the piggy back ecu

3) vmm a new wire for tach sense

4) re-learn the compustar brain with this tach signal

press the I and II buttons simultaneously for > 2 seconds OR the I and IV buttons sim. for > 2 seconds, one flash of the park lights confirms this step;

next, press the III button THREE times, the park lights in a few seconds will flash rapidly three times to confirm reset to default settings.

Install the piggy back, start the car, let it idle down, now press the tach learn button and see if it learns the signal.

If it does not and again chirps three times, then find another wire.

maximumsportz wrote:

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Yea I meter tested the wires both times, both same readings.. Scratching my head here. So there is no way to not use a tach signal just for turbo timer, i don't care about remote start I just want the turbo timer since this car has a turbo.

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no, it needs to know engine speed to know if your engine is on or not .. that's why it still needs to know tach/engine rpm.

I think you should just try another wire, shoudl be fine.

Where were you getting the original tach signal?  Did you install a shielded crank angle sensor?  I can't see why the UTEC would mess anything up, unless its a crank signal and you switched signals.

I would tap in to one of the fuel injector wires.  They are right at the ECU.