[blue90]

Well guys, I just did the top end on my '90 Fleetwood's '92 4.9 with the 7 pin large ICM. The car had been sitting since last May with a burnt valve. Hence the Valve Job. Anyway, initially after the repairs were done the car ran very well. It quickly degraded to totally awful. Rough idle, rich, wet plugs. FPR is ok, injectors new and not leaking down. Holds 41 PSI (ignition on, not running pressure.) New AC Delco OEM replacement plugs, wires, Accel Cap rotor and coil. I'm thinking the ignition module has failed. They seem to do that after sitting unused and being put back in service. Is there any way to check the module except by default? I have 798 ohms at 69 degrees resistance in the pickup coil. That is right at the edge of spec. One other issue is that the plastic around the ignition module wire female connectors on the 2-pin side is all broken and not able to be used. The 5-pin side is marginal. So my questions are:

1) Is the missing plastic going to cause any problem?
2) Is the pickup usable?
3) Any way to prove a bad ICM?
4) Does anybody have experience with the Mallory Hyfire ICM? Do they even make one for this application?
5) Would you just buy a new distributor? By the time I buy a pickup and a module...

I was expecting to upgrade the ignition anyway so this isn't a surprise. Oh, one more thing, I did get a distributor fault code before it went South; but since I cleared them it hasn't shown back up. The only current code is for the Cruise Control servo.
Thanks in advance for any advice.

 

[rustyboltz]

This past week my cadillac failed to start for me one morning and that afternoon I got out the FSM and troubleshoot the distributor and it pointed me to the ignition module. I took my old module to OReillys auto parts store and they have a way to check it out and found out that it was bad. I replaced it and my car starts good. Right now with no cranking. So, if you suspect it is bad, take it to a parts store and have it checked out. My replacement cost me $22.

 

[blue90]

Yeah thanks Rusty. I've got it out. Next time I go into town I'll do that. It isn't my primary vehicle so I am in no hurry. Has anyone tried an Accel or Mallory module? If I don't get any feedback I'll just stick with an OEM. I hate to pull the dist out for nothing. But that pickup is 10 years old and the ohm reading is so close to the bottom of specs. Heck I'm retired and the weather is nice. I oughta just pull it and go through it. I should have done that already.

 

[aeronca36606]

You should be able to remove the module without removing the distributor. Doing it this way you will not need to re time the engine. When you install the new module, Make sure that you use some Thermal Compound between the module and the distributor mounting plate. If you fail to do this, The module will fail within a few months. Be careful though as some of the new modules come with what looks like thermal compound but is actually grease and not suitable to use.

 

[blue90]

But I have to pull it to replace the pickup coil. Reinstalling and retiming it isn't any problem. Thanks for the reminder about the dielectric. I have a tube of it around here somewhere.

 

[cadillac_al]

I've never had an ignition module sorta fail; they usually die altogether in my experience. I'll bet by the time you buy a pick up coil and module you would be getting close to the price of a rebuilt distributor. Did you ever check for codes? A vacuum test would be helpful to see if the engine is working properly and the valves are sealing properly.

 

[blue90]

Thanks for the help folks. Turns out the module was ok and the pick up was bad.

 

[quins90lac]

on the broken plastic pieces if you find a place that sells them let me know as all of mine in side the distributor are all crumbling and cracking apart. so I put heat shrink tubing on them. now if i can only find out whats causing my E41 code when the hall effect switch is still good according to my fluke