Cadillac Owners Forum banner

4.9 distributor questions??? I need advice or suggestions.

975 Views 7 Replies 5 Participants Last post by  quins90lac
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.
1 - 1 of 8 Posts
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.
1 - 1 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.