Rescuing my dads old Fiero GT 1987 (Page 16/23)
Patrick JUL 03, 05:08 PM

quote
Originally posted by Repulsiv:

I also nothed something else, sometimes when I try to start the rpm-gauge does not move at all, and it it suddenly ignites I can see that it jump up.

Does the meter and the ignintion control take the rpm signal from the same place ? ..then I could be onto something here.



If nothing else, you've probably got poor/corroded electrical connections between the ICM, ignition coil, pickup coil etc. Take the connections apart, clean them up, and apply plenty of dielectric grease.
Repulsiv JUL 03, 06:11 PM
I actually have cleaned a lot of connectors to sensors and stuff, but most are some kind of superseal-variant and those seem to protect very well.

But I wonder where the signal come from.. from the distributor ?

By the way I had the car on idle a long time (at least 10min) today and after that it ran a bit smoother.. however the idle is very high, 1800rpm, and if it misfire its even higher for a while.
Patrick JUL 03, 06:24 PM

quote
Originally posted by Repulsiv:

I actually have cleaned a lot of connectors to sensors and stuff, but most are some kind of superseal-variant and those seem to protect very well.



They're 30 years old... don't assume all of them are still completely sealed and/or making perfect electrical contact.

Did you bother re-checking your spark as advised? I saw nothing posted.


quote
Originally posted by Patrick:

It's pointless checking for spark across the minuscule gap of a regular spark plug. That's not wide enough at atmospheric pressure outside of the combustion chamber. A healthy spark will have no problem jumping a 1/4" gap to ground... and it'll do it with a loud "snap".





You can do what people suggest here, or not... and have this thread go on and on beyond the four pages it's already at.

[This message has been edited by Patrick (edited 07-03-2018).]

Repulsiv JUL 04, 02:10 AM
I cannot do that alone, I will try it when I have someone else that can turn the key for me
Rexgirl JUL 04, 04:51 AM
Yes, the pick up coil certainly can fail, which is why I mentioned it. I replaced mine at 70 k miles.

Also, the black ignition module in the distributor is a weak point due to heat, ozone and moisture. Your module's two attaching screws are Incredibly rusty and they *ground* the module. Clean ALL the rust off those screws AND the metal tubes they pass through in the ignition module! And of course, put new electronic silicone heat transfer grease between the module and the aluminum base plate.
You may need to replace the ignition module but if yours is original it may be worth trying to salvage. Consider replacing the screws too, if possible.

Other very common failure parts: Ignition coil, clutch slave cylinder, fuel pump, water pump and suspension ball joint rubber boots (the B.J. need to be lubricated). If you read through the forum, you will learn a lot.
BTW: I suggest you listen to Patrick, he's one of the experts here.
Rexgirl JUL 04, 05:47 AM
Also, the insulated metal tube in the left side of your picture that is attached to under the red intake plenum is the EGR tube. These often crack and lean the fuel/air mixture, causing a high idle.
Patrick JUL 04, 01:31 PM

quote
Originally posted by Rexgirl:

BTW: I suggest you listen to Patrick, he's one of the experts here.



Geez, don't put that kind of pressure on me. I'm just one of many many people here (including yourself) who know a few things about these cars.
Repulsiv JUL 06, 09:44 PM
I have been reading up on the ignition system now, and just as said here the pickupcoil and ignitor module seem to be weak points.. Also oxide in those connectors.

So today I opened the distributor and disconnected the pickup coil, this coil reeally look bad, and also the connectors.. wow, im surprised the engine started at all..



I cleaned everything very well, both the superseal connectors (no oxide there that i could see, but anyway..) and then the pickup coil connector.. this was not very easy
but finally I cleaned them and I measured with an ohmmeter, no contact with ground and 820ohms over it, thats perfect due to my haynes-book.

So it seem to be ok even if it look like sh*t.. however, since they are prone to fail and it looks like it do i will do as rexgirl suggested and buy one..

I also cleaned the connectors to the ignition coul, again they looked fine but cleaned anyway.

When all connectors was cleaned i cleaned the area under the ignition module, the paste under it was rock hard and it took some time to get it away, then i put some fresh
paste that i usally use for CPU's under it and put it back. ..back with the cam and the cables and then off with the cap again to put back the rotor that I forgot ..then when everything was
mounted I tried to start again.

It did NOT heltp, however the car reacts different now.

Before if I tried to start it would usally have the needle on the rpm meeter on zero, and then sometimes pop up to ~800rpm (while cranking) and if it was at zero there was no ignitions at all, when it jumped up it could ignite now and then.

Now however, the needle is at least on 800rpm all the time, and the engine ignites pretty often - but does nto start.. and strangely enough - the needle jumps up really high now and then, sometimes so high it hits the stop.

Very strange.

..Tomorrow I might get some help from my gf, so I can finally try if it can make sparks over a longer gap.. and I readed somwhere that there was some filter for the rpm meter on the ignition coil that could create problems and could be disconnected, just have to find where I readed it..
Rexgirl JUL 07, 04:34 AM
Since your black Ignition Module sends a signal to the tachometer, and then on to the ECM, your IgnitionControlModule is at least working partially now. If you cleaned all the rust off the Ignition Module's mounting screws and it's grounding tubes, it's still possible that the ICM is failing or yes, the tach filter is not operating correctly.
Here is the location of the tach filter (thanks Derrangedsheep) :


and here is the tach filter schematic:


With all that rust and damage, you could also purchase a replacement distributor from eBay if you wish. You want the one with the star shaped reluctor (Cardone (A1) Industries 84-1633 Cardone Select Distributor, I think?). Anyone?
Rexgirl JUL 07, 04:52 AM
BTW, the polarity of the pick-up coil wires into the ICM matters, so it's important that the wires are returned to their original terminal. New pickup coils have a connector that properly connects these wires, but yours has disintegrated. It's also typical that the wires loose their color and appear white, so you may want to use the picture you posted here as a guide.