Im curious as to what the symptoms of a bad icm would be?

I still have a slight problem when its hot outside (78+ degrees) starting the truck. it can not possibly still be my ignition switch since i replaced that twice now. Could it be my Ignition Control Module? I took the coil to get it tested its still good. The problem remains when its hot outside the dash has no power to it until I let it cool down or take a fan and place it in there for a few minutes chilling the entire truck cabin out. But once the temp drops below 78 in the cabin then it starts fine. I did change my coil a few months back, but i did NOT change my ICM.

What about dielectric grease? What doe that do for the coil? I was given a packet of it when I bought my coil but didn't use it. And to think about it, after I changed my coil is when this whole thing began occurring..

The non-use of the grease could possibly be screwing up/frying my icm causing the truck to have no power to dash and such when trying to start it?

and on an unrelated ICM note.. when I do get the truck to start (before turning it over) i do hear my fp kick on. it runs for a few seconds then shuts off like normal. then I turn the truck over I can hear it whining again.. is that normal?

 

I'm uncertain what you mean by 'no power'.. are you saying none of the warning lights cycle.. or are you saying the Fuel gauge doesnt work either.. ??? Did you try localizing the effect? Like shooting cool air right underneath the dash left side.. behind the IP fuse panel?hmmm the ICM is under the hood, right?That would be for the spark lead boot and connector blades.. not as heat sink grease for coil.
It IS imprtant the ICM has fresh grease between it and its mounting plate for cooling however. Whether heat sink grease or just dielectric grease doesnt matter. And I have YEARS of using it on Ford Dist mounted TFI's to back that up.I cant find any direct connection from ignition control to Instrument panel, what made you think that? SOME reference has been made to ICM = Instrumentation Control Module. I thought that was misleading and whoever uses that acronym is .. {expletive}Not to kick a sick puppy.. but "Well, ye-ahhhh!"
j/k i know you didnt think that through because of the other problem distracting you.


Some systems might use the PCM seeing am ignition timing pulse to turn on fp relay, some might use oil pressure switch. Either means the engine is turning over.. whether by starter or own power.

 

What i mean by no power is pretty much i have no warning light cycles. Everything else works such as my overhead digital temp thing (which is how I know how hot it is inside the cabin) But when I turn it to actually start it i get the starter trying to start it but it will not start/run. The starter coil (according to the guys down at Advance) is what gives the truck enough spark to start, along with the plugs. If I disconnect the coil, it wont have the intial spark to start the vehicle. He also called it a starter coil.. when it was listed as Pick-Up Coil.

Yeah the ICM is under the hood, connected with my coil by a screw and 2 mounting plates.

I didn't do any kind of localization. I just put it on my seat, set it to oscillate, closed the door, smoked a cig and tried it.

To further my research, I did disconnect my coil/ignition control and see what happens and I had no dash lights but everything else such as fuel gauge, oil pressure and volts were working.


What made me think of my ICM was from my olds achieva. I kept a log book of it.. since it was going to be my "learning motor". I found my log book where I had written down everything that was wrong with it and what i did to fix it. It had the same sort of behavior starting when I first got it. According to my log i put "Does not want to start.. no dash lights.. starter is working.. just not starting up" Due to a tip from my eldest brother, who was having the same problems in his trans am, I had my other brother change the coils and ignition module (because I was afraid of F.U.B.A.R.) and the problems all went away.

I read somewhere on here to coat it with the grease and it helps it, which is what made me think of that and that it only goes screwy when its hot outside.

Since I didn't put any kind of grease between the plates when i did my coil, that could be my problem since it is important to have that? When i did my coil, I know I had to remove the ICM because I remember having to drill the damn rivets out. Once I did that, I took it all the way apart and just looked at the 4 pieces all proud of myself because I thought that was a major accomplishment to do.

ha ha ha yeah I was hoping the fp was normal. I just couldn't remember for the life of me if it always did that. And i never paid enough attention to my previous vehicles before to notice it.

 

hey pettyfog, when you asked if my fuel gauge worked, what did you mean by that? Because this problem is still showing up randomly now. its gotten colder outside and it has its good days and bad days.

I ask about the fuel gauge because today when leaving work, right after pulling out into the street actually, it did it. it died and wouldn't turn but i noticed that my fuel gauge went from 1/4 tank down to empty then all the way past full. And my volt gauge went all the way to right as well.

Is that what you meant by did my gas gauge work?