Alright guys, lately I have been having trouble getting my car started every now and then. Some times it fires up just fine and others it just sits there and cranks and doesnt get any spark. It mostly does this in the mournings. Sometimes I can turn it over and tap the tap with a wrench and get it to fire up but only sometimes. I was thinking ignition module but because the distributor I bought was pretty cheap and from a no name company I was thinking maybe its to blame. What do you think? I appreciatte the help guys.

 

It is possible that you have a failing HEI switching module. However, the typical failure mode symptoms include a reduced or no primary coil current after the module has been heated from driving, not on a cold start.

If you have determined that you are lacking spark instead of fuel, I'd suggest inspecting the distributor connections very closely, both those to the chassis wiring harness and the internal connections from the pickup coil, to the power wiring, and to the ignition coil.

 

At first I thought the wiring was the problem, but I went over it and it is fine. Today it wouldnt start all day until I took the cap off and cleaned everything with WD40. Then it started but after I turned it off it wouldnt start again. So you think its the HEI switching module. Which i take is not the same as the ignition module.hmmm....... I am getting very frustrated with all of these small probs. I need to be out enjoying all of the power off my new engine. Ive only really driven about 10 times since getting it running more than a month ago.

 

The "ignition module" is the HEI switching/amplifier module - Same thing. That's what the "ignition module" does.

For the cost of a good module, it might be worth a try, but many places can test them for free.

 

cool, i will go and have someone test it this week. Thanks for your help Vader.

 

If your module is taking a crap on you, be advised that Accel, pertronix, and at least one other aftermarket supplier makes hi-po replacement HEI modules. You can get 4 pin, 7 pin and 8 pin modules from these guys.

I'm wondering if anyone has any experience good/bad with any of the aftermarket hi-po 8 pin modules?

 

4 pin, 7 pin or 8 pin. Which one to use? Or do any of them just simply attach right on in place of the original?

 

The one that fits your car.... i.e. has the same number of pins as the one that's there now.

If you're asking about any of these cars in stock or CA-smog condition, it won't be a 4-pin; that's for non-computer distributors. All of these cars had computer controls. So it will be either the 7- or the 8-pin one.

 

Thanks for such a quick responce. Now, does the module fail suddenly and completely or can the fail gradually? My car runs great while accelerating but it goes "jerk-jerk-jerk" when holding the throttle steady at speeds from 10-65mph. (mildly jerking) That's as fast as I took it. New plugs, wires, cap/rotor, O2 sensor, air filter, pcv. Coil checked out ok. I am surprised the "service engine soon" light does not come on. No codes stored in the memory. I bought it from the original owner a couple months ago. It's in very good shape. All stock and everything in the right place. Found receipts for MAF, TPS, IAC, and ignition module all replaced about 6000 miles ago in March 2003. I would like to isolate the problem myself, gaining knowledge and saving hundreds of dollars!! Thanks

 

They are all junk, stay far away from them. Use ONLY AC Delco for the ignition module or you will regret it later.

 

If you have a computer controlled engine, you'll need the 7 pin or 8 pin modules. The 7 pin was for distributors with the coil in the cap. The 8 pin was used for the external coil setups (like my 88 LB9). The 4 pin module will NOT work in these applications. Get the right module!

The correct replacement module will indeed "simply attach right on in place of the original". Be sure to CLEAN off the mounting surface on the bottom of the new module, AND the corresponding mounting surface in the distributor. Get ALL the junk, dirt and gunk off the mounting surfaces. It's gotta be clean enough for you to lick. Then go to a computer geek store and get a tube (looks like a small plastic hypodermic needle) of Artic Silver heatsink compound. Put this stuff on the bottom of the module, spread it around with your finger to get a uniforn THIN layer. Then clean your hand so the stuff doesn't get all over everyhting else. Mount the unit down with this fresh compound in the distributor. Reconnect the wires and you should be good to go.