My 1991 OCC with 305 TBI coming home this morning, her engine just quit in the middle of the road. No bang, no fuel sputter, no weird noises, no visible damage anywhere. Starter cranks the engine but it doesn't turn over. Fuel pump went last year and was replaced, but that had different symptoms. (Back then she tried to start but sputtered and died like a mower running out of gas.) Checked two different plugs with a plug tester, no light. tested the coil wire and no light between the coil and distributor. I then tested the spark tester on my known running 70 Olds, just in case the tester wasn't working, and it flashed like it should. I have a replacement coil, but is there anything else I should I check before I replace it?

 

Something similar happened to me on a Ford and it was the ignition module.

 

I would be more inclined to look at the HEI module in the distributor. Coils dont usually just fail all of a sudden like that but it can happen.

Does yours have vacuum advance ? If so the little wires in the distributor that go to the pickup coil can break after a while from flexing back and forth. Not usually a problem with the non vacuum advance distributors.

The GM service manual has a step by step troubleshooting procedure that pinpoints the problem.

 

X2, ignition module, easy fix

 

Also, I think corrosion on the bottom of ignition module can be issue.

 

A remote coil, small cap HEI? The caps corrode badly. Every time a TBI truck came in with rough running, we changed the cap and rotor first with a Bluestreak one. Most looked like **** and needed replaced.

 

I think it's best to find a cap with real brass terminals, although it might take some research to find one. The caps with aluminum terminals corrode badly.

 

I'd bet a cold beer its the ignition module. Once in a while the pick up coil fails. An easy test to determine a bad coil vs the module is to check for injector pulse. If the ignition module fails you'll lose both. If its the coil the injectors will still pulse but you'll have no spark.

 

You mean the fuel injectors? Okay, I'll check that this afternoon.

 

If it is the HEI ignition module- for your car I think it's the one that's got 2 plugs sticking out of the side of the weird distributor cap on it for the coil and ECM, and the tiny distributor pickup coil plug on the other side that bolts onto the housing. Delco D1984A or equivalent. Kinda pricey. If I'm wrong, then forget what I just wrote.

Regardless, ENSURE you use heat sink grease on the contact area where it mounts on the new one. Some people don't anything, and others use plain dielectric grease that is NOT heat sink grease which is not the proper grease. Ensure it says it's for heat sink use on the label. It usually is dielectric grease anyway. Sometimes modules come with the heat sink grease packet, so use those. DON'T be tempted to use the dielectric grease packs from distributor cap kits if you have any of those. It may be the same, but it may not be.

You don't need much. But it has to be the correct stuff. I have a tube of Super Lube 98003 heat sink dielectric grease, and a little goes a LONG way. Have had that same tube for several years and works well. Never had an issue with it. Anywhere you need dielectric grease and/or heat sink grease, this does the job. Doesn't harden and doesn't thin and run out with heat.

You can get the Super Lube brand about anywhere like Home Depot, Amazon, etc. It doesn't have to be that brand, but it's just what I use. Around 15 bucks per tube. The dow-corning stuff is like 60 bucks per tube.

 

Finally got Bertha running today. I replaced the coil on Friday and was unsuccessful. Snow yesterday hampered efforts but I found chart C4 in the shop manual and was able to run it down to the HEI module today and voila, she is now running. Verified timing and go to go. luckily I had both coil and HEI module in my spare parts collection. Thanks for all the help!

 

Bertha..,, You named your car Bertha? And your wondering why she failed you? I can acknowledge that the B body wagons are rather full figured, but......Bertha? People ask me why I chose a sapphire blue wagon in the heat of Texas, and I always reply that you shouldn't dress a full sized girl in white. Could you imagine Bertha Rabbit instead of Jessica? Perhaps Bertha Vergara rather than Sophia, or even Bertha Hendricks as opposed to Christina??! A little sweet talking and affectionate pet names will get you a lot further down the road of life. Granted, as I'd advised before, the module was the mechanical culprit but you've got to do better than "Bertha" if your hoping for a long term relationship.

 

Funkwagon455, my wife and I thought it was funny to name her Bertha with the big butt!!!! Heck, my son named my other wagon Norman after my late dad because he had the same car. Our 70 98 is named Cindy because Astro Blue looks like Cinderella's dress color.

 

I don't think I set the distributor back to the right spot, now she hesitates and seems sluggish and jumpy. I'll have to recheck the timing, I think I may have accidentally retarded it. The marks were really hard to read especially through the tube thing as I was trying to get it to zero. It was at +2 before and was pinging. The pinging is gone but the car doesn't seem as spritely, well spritely for a 4500 pound, underpowered wagon.

 

Since I had trouble seeing the mark with the timing light, apparently I had retarded it like 10 degrees, off the marks. I used my 80's timing light instead of the modern one and its light was much brighter and I was able to see the numbers on the mark. It is at 0 now, the setting on the shroud sticker, and has plenty of power but the constant pinging under load came back. I wonder if I retard it one degree at a time if I can calm that. Does anyone else have problems with pinging under load in these wagons?

By the way, what is the metal tube above the timing marks for? It sure doesn't point at the marks.

 

Are you disconnecting the electronic advance connection on the passenger side of the intake prior to taking your reading?

 

Yes and she runs as well as before she died now. It's just the blasted ping I've been trying to get rid of for 5 years. When she was super retarded, the one good thing was no load ping.

 

Is the egr valve working properly ? If not it can cause pinging.

 

Thet engine is equipped with a knock sensor system, have you tested the operation of this system? This can be monitored with a scan tool, or if you do not have access to one, the service manual has a method of tapping on the block with a hammer and measuring the sensor output with a voltmeter.

The tube above the timing mark is for a timing probe that some old ignition oscilloscopes were equipped with. These worked very similar to early crankshaft position sensors. The probe picked up the groove in the balancer so you could adjust your timing without shining a light.

 

I replaced the knock sensor a couple years ago. The EGR was a thorn in my side for 2 years until I figured out I put a bad new in box solenoid in. When I removed it and put the original back the check engine light stopped and code 32 went away. After I drove more today the ping was less but not gone. Maybe the computer needs time to relearn.

 

The o-scope thing would be pretty cool if you could find one.