First: 85 SE V6 4 speed (original owner) Car has been running perfectly. It's in brother's spare garage for the winter. So, I disconnected the battery (ground) cable to remove the steering wheel. I didn't want the horn to be honking. Got the steering wheel recovered, and re-installed. Hooked up the battery, and tried to start it. I can hear the fuel pump running, the starter turns over, but it won't start. Pulled the coil wire, and no spark. Tried another coil on it, and still no spark. I checked the IGN fuse, and it looks good. What else could have blown by disconnecting/reconnecting battery cable? In 33 years, this is the only time this car has failed to start. HELP!
Ignition Control Module. Is that what's in the distributor? If this is bad, the tach would not register? I'll check the tach next time. I'm not currently at the car's location.
[This message has been edited by sledcaddie (edited 12-10-2018).]
yes... 2 screws, don't lose them and clean them up.....they are the ground for the ICM. Remove Dist. cap (wires attached) and 2 connectors. It's a fussy cramped little job. When putting the cap back on do not pinch any wires. ICMs are not well made....get a Delco if you need one.....If it is the original ICM I suspect you need one.
[This message has been edited by Gall757 (edited 12-10-2018).]
Yes, it is the original ICM. I've had a coil fail before, but this is a first for the ICM. Thanks so much for your help. I've had another guy from our local club suggest that I replace the entire distributor. Maybe next summer. It's been in the teens here.
Forgot about the thermal paste. If you do need an ICM, make sure it has white goop that you put on the contact surfaces.....some are sold with clear goop....not the right stuff.
di-electric grease is an insulator. It's purpose is to keep moisture out. Thermal paste is a heat-transfer compound usually with conductive powdered metal as an ingredient. It transfers heat from the ICM to an attachment plate. It is used in computer construction.
I cranked the engine, and the tach didn't budge, so I'm thinking it's a bad ICM (like you told me). The new one did come with the white "paste". Where is this supposed to be applied? I've searched the service manual, and I couldn't find any mention of it. Earlier, you said that is goes on the contact surfaces. "Contact" meaning the pins in the sockets? Again, thanks for your help.
[This message has been edited by sledcaddie (edited 12-12-2018).]
Okay. I found an old Pennock's post from 2005 explaining about the thermal paste. They said to clean off the base plate really good, then smear the paste on the plate where the ICM mounts to. The paste is supposed to help the ICM not absorb too much heat. Is this what you are saying, Gall757?
That is exactly what it does. I carry a spare and the tools to chage it in the car at all times... and yes I have changed one on the side of a highway in the cold, it's ALOT easier than walking or dealing with a tow. They will go out when they want. Normally with no warning at all.
Originally posted by sledcaddie: The paste is supposed to help the ICM not absorb too much heat. Is this what you are saying, Gall757?
No....that's not what I'm saying. The ICM generates heat. The paste transfers heat to a metal plate away from the ICM. You need just a thin film on the contact surfaces.
The paste is supposed to help the ICM not absorb too much heat. Is this what you are saying, Gall757?
quote
Originally posted by Easy8:
That is exactly what it does.
No. Just no.
It's amazing how many people have no idea that the base of the distributor is basically the heat sink for the ICM. That lil' sucker gets hot. Gall has explained it well.
Thanks to ALL for your inputs. Once again, the people on this forum provide great information to the Fiero community. It is often much clearer than what is shown in the service manuals. We all want our cars to run the best that they can. Everyone sharing their experiences helps achieve that goal. I salute all contributors.
Pull tach filter when having ignition problems. Heat Sink grease is good here. White is Silicon or other "oil" and Zinc Oxide. Clear is just plane silicon and works too but not as well. Don't bother w/ Silver Hype and other high dollar HS grease pushed on most PC users. Iffy mounting screws can fake dead ICM and/or Dist's small coil. 1 or rarely both Screws are the ground "wire" to the dis base metal on most ICM for Fiero and others.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Just a follow-up. I pulled the cap and rotor first. Although only about 4 years old (not that many miles), all the terminals were corroded. Pulled the ICM next. The 2 screws were REALLY corroded, as were the 2 sleeves in the ICM body. Cleaned off the base with scotch bright pad (now nice and shiny). Was going to replace the 2 screws, but they are a really odd size (3.5mm X 19mm). Of course, nobody has them. As suggested on Pennock's, I tapped out the holes to 6/32", and put new stainless screws in. The new module (not GM) came with a packet of the white thermal paste. Applied that to the module plate and installed with new screws. Installed new cap and rotor, and it fired right up. I'll probably replace the entire distributor this summer. Everyone seems to believe that the genuine GM module is the way to go. When replacing the entire distributor, does that mean it should be genuine GM too? I would think that there are quality after market distributors out there (Accel or MSD). Any recommendations? I tried the Fiero Store, but their distributors are rebuilds.
[This message has been edited by sledcaddie (edited 12-14-2018).]
There are new and rebuilt distributors available from Cardone, which seem to work very well. You can also rebuild your distributor with good results. There are videos available to show you how. I have not seen a GM branded distributor in years.
