I all most got hit today, when i stood on the breaks and clutch, my foot didnt quite go quick enough for the clutch, and my front tires locked up, and i stalled my engine from about 40kmh. heres the major problem, my Service Engine Soon light stays on, and my Compustar refuses to start. it reads no tach signial. i install remote starters for a living, and i know that all my conections are good. oh ya, when i accerliate and stop, the engine seems to lag, and almost want to quite. what might cause this problem. could it posibly be the coil pack, or the MAP sensor. i need to figure this out, cuz i dont really want to drive my car till i get it fixed. mostly cuz money is really tight right now.


Travis Nobert
Travis Enterprise
Come on down to Evolution Audio in Edmonton Alberta, and I can HOOK YOU UP.

Does the engine not start at all, or is the Compustar just not getting a tach signal?

using the key i can start the car. in order to use the compustar, i must put the car in nutrial, then pull the e-brake, then the compustar will take over till i get out of the car, but instead id does not take over. using the key i can start and stop the car all i want, but untill i can make the tach signial reapear the Remote starter will not work, only the alarm part works.


Travis Nobert
Travis Enterprise
Come on down to Evolution Audio in Edmonton Alberta, and I can HOOK YOU UP.

To answer your question, the MAP sensor will have nothing to do with the tach signal; it reads pressure.

If there was a bad coil, you'd know it, as the engine would either not run or run like ass. Do two things: run the code that's causing the light to come on, and (even though you said they were good) check all your Compustar connections, because if anything that a tach signal could be read from was bad, the car would show it.

trust me, i checked all the conections, and re checked, them, then checked them again, un-pluged the module, and still all the same things.


Travis Nobert
Travis Enterprise
Come on down to Evolution Audio in Edmonton Alberta, and I can HOOK YOU UP.

The tach signal in a 2.8L generates from the crankshaft sensor. As the reluctor ring on the crankshaft rotates, the notches in it are read by the magnetic pickup of the crank sensor. This gauges at how many RPMs the engine is turning, and sends this signal to the ignition module, which controls the firing of the coils.

Translation: If anywhere in this circuit was experiencing an interruption, THE CAR WOULD NOT RUN, as it would not be recieving spark. Meaning, if the car is running, it's seeing everything normally. If the Compustar isn't operating, it's an issue in that system. Sorry.

okay, but i cut that thing right outa there, i got a little mad, so i took it out, and the wire that was used for the tach, was ground opposed to AC. and it would run. so again, could it be one of the three coil packs. because i think (NOTE i am not an expert, i could and most likly are wrong) that if only one coil pack is wrong, the motor would run like carp, and it would still run, and if the coil pack is gone, then the tach sensor could read false, and could make the check engine light turn on. am i wrong, cuz im starting to confuse my self.


Travis Nobert
Travis Enterprise
Come on down to Evolution Audio in Edmonton Alberta, and I can HOOK YOU UP.

If one coil was bad, it would cause 2 cylinders to misfire, but yes, the engine could stay running. It would also cause the SES light to come on. However, the coils are nothing but spark-senders. The tach signal is generated before the coils fire, not after. A bad crankshaft sensor (what generates the tach signal) will cause the coils not to fire. If the engine is missing, it won't have a normal tach signal, but one will still be present.

i grab the tach signal from the output of the ecm, there is a input there the tach signal will go to the RMP gauge, and from the coils, put i grab it from the other side, coming from the coils. so we both are right, the coil is bad, causing the light to turn on, and veichle to lose power. right. so all i have to do is replace the coil packs, and everything should be fine. but if not then what should a guy do¿¿¿


Travis Nobert
Travis Enterprise
Come on down to Evolution Audio in Edmonton Alberta, and I can HOOK YOU UP.

your on the right track try replacing your o2 sensor and check all your vaccum hoses that go into the intake. good luck

the O2 sensor would make the CEL come on. so possiblly it might just be to O2 sencor. i'm thinking of getting a new car so i dont have to fix this car all the time. but i put to much money into this one. so guess ill just keep it. what do you guys/gals think?


Travis Nobert
Travis Enterprise
Come on down to Evolution Audio in Edmonton Alberta, and I can HOOK YOU UP.

This may be a silly question, but could it be related to any wiring attached to the brake light switch. Maybe when you stood on the brakes, you dislodged or broke it. Sorry if this is a dumb suggestion. Good luck.

no i checked the wires when i checked my alarm starter. i never thought about the O2 sensor. and all that that would do is make my breaklights not turn on. remember my car is an '89. the computer doesnt chech to make sure all the conections are conected. i found that out one day when i unpluged it to get at the right wire, and forgot to plug it in. nothing really happened.


Travis Nobert
Travis Enterprise
Come on down to Evolution Audio in Edmonton Alberta, and I can HOOK YOU UP.