I have a 88 SE and Im in the middle of reinstalling a motor I rebuilt. As stated above I can get the spark plugs to fire. I have replaced the coils from a parts car (87 GXL) I have and I have seen those coils make a spark before so Im fairly sure the Coils/Ignitors are ok. Im starting to suspect the ECU but when the one from my parts car is a different model (N326) instead of N327 so I'm not sure if I can test it just by swaping them. However, I took the ECU out and looked at the PCB and it seem to be in good shape none of the electrical components seemed damaged and I seemed to have a good voltage at the pressure sensor of pin A2 (above 4.5 volts). If it isnt the ECU what else could it be? is there a fuse or something that I am missing? and helpful insights would be much appreciated. Thanks.

-Dan

I think you meant "can't" instead of "can" in the body of the text.



Check for power at the coils. If there is power place the plugs by a ground, a bolt or something, and have a buddy crank the car. You should see sparks. Don't worry about it if the trailing don't fire for now. If you are still not getting spark from the coils make sure all fuses are good and then there is a way to check the coils if they are good but it involves splicing the trigger wire to the coils and touching it to ground with the power on.

Check for power at the coils 1st as mentioned.

I have voltage at both the leading and trailing coils I just checked. I dont think the ignitors are getting a signal? what is the best way to check this?

Well, there is a way described in the FSM but you need a special tool. The way I know of involves splicing the trigger wire, the wire next to the power wire (pink or tan, I forgot). It is the one we use to hook up the Haltech. If you were to cut that in half you could then quickly and shortly ground that wire with power to the coil and it will spark.

Thanks Cosmo Donk for that trick Im going to try that, but I'm going to disconnect that wire from the coil at the little nut instead of cutting the wire, and run another wire to the ground to test it, is there anything wrong with this logic or do I have to splice it? Also does anyone know what the difference is between the N326 and N327 ECUs?

Nothing wrong with that logic, although I don't know the nut you speak of. Just as long as the trigger wire goes directly to ground and you do it quickly.



Dunno about the ECU's.



Hope it works and please post your results.

Now you have to check if the CAS is within spec. The fsm lists the resistances it should be within. Then you have to test if the cas is sending its signal to the ecu and if the ecu is getting it.

I tried Cosmo Donk's ignitor testing trick by cutting the Pink wire on both of the leading coils I own. I briefly touched the now exposed ignitor wire to a ground wire that was attached to the negative battery post. the coil had power when I did this test and I tried to ground out the spark plugs on just about everyplace I could thing of in engine bay. Still no spark! Is this test conclusive that both my leading coil/ignitors are FUBAR? because I know that the leading coil from my parts car was able to make a spark. Could something else be causing the ignitors not to fire? or what could be killing my ignitors?



I checked the CAS and the resistance is within spec.



also what is the best way to check if the CAS is sending signal to the ECU? can I just check continuity?



BTW Thanks a lot for the help Cosmo Donk and 1Revvin7

yea, you can go to the pins at the ECU. I got the picture somewhere. Lemme find it. Anyways, you just ring the wires to each other, meaning that you just measure the resistance between the 2 wires. this will tell you if the signal from the CAS is getting to the ECU. Basically you are checking the wires in between for a short.



There, test pins N and P, and then pins T and Q. Just check with a multimeter set to ohms.



Ohh yea. To find the pins you are looking for pull the big plug of the ECU. The pins are lettered looking at them from the wire side, not the side that plugs into the ECU. To find those pins you start counting from the top right. This is A direcly under it is B and to the left of A is C. Just count until you find the pins you need.

I might add to make sure the coil is grounded. It uses its body which has to be bolted down to creat a good ground. If anything make sure you have plenty of good grounds. I would go ahead and add some anyways, couldn't hurt and it just might be whats causing this.

Good point. I forgot to say that. With mine I ground off the paint where the coil hooks to the body.



If I remember right this is a conclusive test. With my working ignitors (coils, whatever) the dead one did not spark but the new ones did.



I thought I had the e-mail from Matt about this testing but I just looked at my website and it definitely is the pink wire that triggers it.

I already cleaned up the ground on the coils and Ive been adding lots of grounds as I go.

The CAS wires N P and T Q all had continuity so that shouldnt be the problem.

When I had this problem EVERYTHING checked ok. I was stumped. Nothing that I could tell was wrong. So after trying to fix it for a week I finally just said fug it and decided to move it into my garage. Well I somehow got it started and moved it. I let it sit in the garage running for about another minutes or so and when I got went to check it again the leading coil had come back. Still don't know what really caused my problem, I'm guessing it was a grounding issue. Just like that POFF my problem was gone...

Did you check if the coils were within spec?

I made a test light out of a couple LEDs and ran it between the ignitor source wire from the ECU direct to a ground, bypassing the leading coil. when I cranked the motor the LEDs never blinked at all. I think that my ECU is dead is there any way to check for sure?

1Revvin7: I checked the resistance of the coils and they were within spec.

double post

Im going to reground the whole car tomorrow, not sure what else to do.

would it be stupid to plug my N326 ECU into a car that came equiped with N327? they are both S4 NA?

It should work with a year/same series ecu I would think. I have swapped ecus on a t2 before with no ill effects.

Ug, I remember there is a way to see if the ECU is fried. You grab the pressure sensor wires (The ones on the pass. shock tower). You have to test one of the wires in there, I forget which one though. But anyways you test if and it should have 5V on it, if it doesn';t your ECU is toast. Give me a minute to find out which wire it is.

That could just mean your ecu has no power. Test to see if any of the wires going to the ecu are hot while you are at it. If they are at the pressure sensor is not, then its fried.

I had already checked that wire on the pressure sensor and it checked out. Is there a good way to check if the leading ignitor trigger wire (the green/yellow striped one) is carrying a signal?

Why did this start happening in the 1st place? Do you have x15/16 connectors plugged in? They are up in the corner near the ecu but not plugging into the ecu...

Well, if my method of triggering it with ground makes it spark the trigger wire should be a pull to ground. If that is correct you should be able to do a continuity check when cranking from the trigger wire to ground. It should beep (continuity) when the signal goes through.



BTW. Did you try my test? - EDIT - I see you did but the coils seemed dead. Have you tried any other coils? - EDIT - Never mind:)

1Revvin7: This is happening because I bought the car and it never ran so I rebuilt the motor. I'll check the X15/16 connector sounds promising.



Cosmo Donk: are you sure grounding out the ignitor wire is what triggers the coil? I think the ECU sends 5volts to trip the ignitor based off the CAS signal. Please someone correct me if this is incorrect.

I am just curious, are you getting any spark at the trailing coils?

No spark on leading or trailing

Well, if your sure absolutely everything is connected, I want to say your ECU is fried. I never really hear about coils just crapping out, let alone both of them at the same time.

I regrounded the ECU really well and even though my battery now has barely enough power to spin the motor I saw a tiny spark this time. I'm pretty sure it was the ECU not having a good ground.

do you know the ECU grounds, the ones that actually plug into the ECU? I can't remeber offhand. Someone posted a thread with all the ECU gounds in it. That should help a lot.

Get some thick wire and the proper connections for it. It will pay off in the end.