rico05

I was driving, and my tach quit working, and the check engine light went on!!! The car drives fine but WTF!!!!!!!!!!!!!

niner

same thing happened to me...

check the code. it might be for the trailing ignition.
w/ mine there was a bad ground to the trailing ignition, so light would come on at same time tach died
i have an auxiliary ground for the trailing coil now-problem fixed

that is... if it is that. good chance of it though

rico05

But if the coil died, then wouldn,t the car not run right?

rico05

Help, again!

niner

no, no. that dosnt mean the coil died
just that there is a bad ground on it. the tach runs off of one of the wires in the connector on the trailing coil. if the ground wire is bad then the tach wont run, but the coil still can work fine. it will just set the code off also

there is a good chance that that is the problem, but i cannot guarantee it.
clean up the grounds and then run another one to a real good ground

Scott 89t2

the car can run off only the leading coil. so it's possable the trailing one is dead. that's where the tach signal comes from.

rico05

But it dosen't pull any different! I guess I am still reaping the pussishment for my grounding mistake!

niner

scotts right, it might be that the coil is dead also
pull a wire off from trailing coil and put a screwdriver in it and hold it close to the engine and see if you get spark when someone turns motor over-be careful not to shock yourself
if it has strong spark then it might be the ground or something
thats just how it was w/ my car

Scott 89t2

I don't know if I'd trust him to 50,000 volts.. he can't even handle 12 please keep the screw driver away

rico05

Very Funny Scott.

rico05

This is all b/c I trusted someone who said"connect the positive battery terminal to the nut on the alternator", not specifying which one! OOPS!

Josepi

Easier, and safer way to check for spark:

All of this of course is presuming that your spark plug wires are in working order.

1. Grab plug wire from T1 spark plug, should be top left. (IE disconnect plug wire from plug)
2. Keep it connected to the trailing coil.
3. Take spark plug wire and put it on the fender.
4. Crank.
5. See a spark?

This would and did work for my 83 GSL, the tach on it worked, but my leading was bad. Yes you can run off of 1 plug per rotor, just not the same. If it was your trailing, you most likely wouldn't feel it too much due to the function of the trailing plug.

You could also check the coils resistance per Haynes manual.

If your not getting spark from the trailing coil, check the coil, then check everything that fires the trailing coil.

demonracer

And like Josepi said, if you check for spark that way make sure you hold the PLUG WIRE NOT the end of the BOOT

OPEC

Rico05 PM Sledgehammer my previous 90NA that i sold him did the same thing.. and i tried everyting to get it to work, coils, ecu, everything. I finally gave up, he did something to get it working again, and now it is great. I think he redid a faulty fire on the ECU connector that had come loose or something.. But PM him and I am sure he will tell you what he did..

natedogg

FCs have an engine light? I never knew! That tells you the condition of my car

niner

um... you should see that light everytime the key is on the "on" position
maybe that means the condition of your car isnt so good if the last owner unhooked the engine light

Silkworm

ROFL

Paul

NZConvertible

Natedogg, only Series 5's have a check engine light, not your Series 4.