TBI Ignition Module dead after a few cranks

[eclipse85k10]

My 89 I've been chasing a gremlin for a while. Cranks and no fire. Last ignition module failed the test at the auto parts store. Bought a new one and checked thru all the wiring harness. Cleaned up some ugly wires and wrapped them good. I added an extra ground from the block to the frame. Put it all back together and went to start it up. It started to fire up and quickly died. Few sputters after that and then no fire or sputter.

I pulled the new ignition module and taking it to get tested.

 

[dyeager535]

Apparently a bad coil can cause this. Other than that or a short somewhere, I cant see what else would cause it. Obviously you need to use the conductive grease under the module on install, but even without that, I assume it would last more than a couple of seconds.

I hate to say it, but if this is the original distributor, you may be better off buying a complete replacement, to include cap and coil. I think they are now under $80.

Some parts stores will let you "buy up" if going from something like a module to the distributor. Last I bought a parts store module (bad idea, it was the pickup coil) I want to say it was $40. Which is why the complete distributors are a better deal.

You can test a coil, but sometimes this sort of stuff only presents itself an issue under load.

 

[diesel4me]

A bad pick up coil can fry a module too..if one shorts to ground it'll fry the module..

 

[dyeager535]

A bad pick up coil can fry a module too..if one shorts to ground it'll fry the module..

Should be able to test that pretty easily. If I were doing that I'd make sure none of the module wires are shorted to ground either.

 

[rampage]

Should be able to test that pretty easily. If I were doing that I'd make sure none of the module wires are shorted to ground either.

If only there was a tool that could do that.

 

[eclipse85k10]

Does the coil ground though mounting bolts in the intake?

 

[eclipse85k10]

Update....

After talking to some different mechanics one suggested a crazy thought. He said the factory Y-pipe in the exhaust is double walled and it's possible to collapse inside. I got home and removed the exhaust at the collectors. Took some work dialing the fuel and Ignition back up again but it fired up and is running again. Time for a visit to the muffler shop.

 

[diesel4me]

I recall a early 70's Buick Electra we had in shop class that belonged to the Carpentry shop teacher ,had the Y-pipe collapse internally on his 455 V8,it would only run below 2500 rpms or so,any more throttle would make it want to buck & stall out..

Even the auto repair shop teacher couldn't figure out what was wrong with it--our teacher hooked up a vacuum gauge and watched it as he gunned the engine,and noted when he let off the throttle,it took longer for the gauge to return to normal readings compared to another car we hooked it too,which indicated excess back pressure..

We replaced the Y-pipe and the car ran good again..the auto shop teacher was a bit miffed our teacher solved the issue--didn't believe the Y-pipe was the cause,he insisted he'd found some other problem he wasn't telling about--he cut the old Y-pipe up into 3" pieces and sure enough,about 8" past the passenger side manifold,the double layer of pipe was collapsed almost completely shut for about 3" !..

I've seen clogged catalitic converters do the same thing,and some had the "guts" blow out of the converter,and got stuck in the muffler baffles,causing an intermittent stalling or "no power" issue ..

 

[Wes Harden]

yup I have had this on customers cars, but I though GM stopped that sh(t in the 70's. I have only had cat's stop up on later models

 

[eclipse85k10]

I've heard of cats causing the same issues. I had my exhaust replaced removing the cat and all new 3 inch singled off with a flow master 40b series. I would have never guessed a back pressure issue but it makes sense now. Just need to get my exhaust built from the collectors back to the newer 3in pipe and hopefully be on the road again.