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 1991 OCC TBI Coil Bad?

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smparr

smparr


Posts : 190
Join date : 2018-12-18
Location : Bremerton, Washington

1991 OCC TBI Coil Bad? Empty
PostSubject: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeWed Jan 18, 2023 9:44 pm

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.  No codes in the ECU. I have a replacement coil, but is there anything else I should I check before I replace it?
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Fix Until Broke




Posts : 219
Join date : 2019-04-05
Location : Southeast Wisconsin

1991 OCC TBI Coil Bad? Empty
PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeWed Jan 18, 2023 10:08 pm

Starter cranks but doesn't turn over - Can you clarify what that means?

Ignoring that bit of confusion, do you have power to the distributor during cranking?

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smparr

smparr


Posts : 190
Join date : 2018-12-18
Location : Bremerton, Washington

1991 OCC TBI Coil Bad? Empty
PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeThu Jan 19, 2023 12:59 am

It never tries to fire. Starter just keeps turning the engine. I have to get the air cleaner off tomorrow to check the injectors but I can smell fuel as it turns. I'm working 12s at night right now so short of time to work on it. When I put the spark tester on the coil wire to the distributor I get no flash and no flash when attached to any plug. I checked all the fuses and none were blown. What other wire on the distributor should I check? The two plugs on the ignition module maybe?
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Fred Kiehl

Fred Kiehl


Posts : 6705
Join date : 2009-11-13
Age : 74
Location : Largo, FL 33774

1991 OCC TBI Coil Bad? Empty
PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeThu Jan 19, 2023 8:52 am

It could be anything from the ignition switch to the wires from the detector coil to the module in the distributor. Check for B+ at the coil input (pink) with the Ignition on. You may have to remove the distributor to check the other wires. It could be the ignition module.
Fuel pump, and injectors appear to be good.
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rcktpwrd

rcktpwrd


Posts : 472
Join date : 2019-03-06
Age : 48
Location : Raleigh, NC

1991 OCC TBI Coil Bad? Empty
PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeThu Jan 19, 2023 7:12 pm

My wild guess is the ignition module...
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smparr

smparr


Posts : 190
Join date : 2018-12-18
Location : Bremerton, Washington

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PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeSun Jan 22, 2023 9:12 pm

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!
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smparr

smparr


Posts : 190
Join date : 2018-12-18
Location : Bremerton, Washington

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PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeMon Jan 23, 2023 11:17 pm

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. Very Happy
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Fred Kiehl

Fred Kiehl


Posts : 6705
Join date : 2009-11-13
Age : 74
Location : Largo, FL 33774

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PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeTue Jan 24, 2023 7:07 am

Remember to disconnect the connector on the PS valve cover when you are setting the timing.
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smparr

smparr


Posts : 190
Join date : 2018-12-18
Location : Bremerton, Washington

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PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeTue Jan 24, 2023 9:35 pm

I disconnected the ECM plug last time but 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 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?

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

Fred Kiehl


Posts : 6705
Join date : 2009-11-13
Age : 74
Location : Largo, FL 33774

1991 OCC TBI Coil Bad? Empty
PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeWed Jan 25, 2023 8:14 am

Make sure your knock sensor is good.
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goldwolfnhn




Posts : 315
Join date : 2019-07-11
Location : Stevens Point, Wisconsin

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PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeWed Jan 25, 2023 10:13 am

My 87 Pontiac with 307 pings alot under load with regular unleaded but with mid grade it pings less and with premium it didn't ping at all.
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Fred Kiehl

Fred Kiehl


Posts : 6705
Join date : 2009-11-13
Age : 74
Location : Largo, FL 33774

1991 OCC TBI Coil Bad? Empty
PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeWed Jan 25, 2023 10:23 am

I hope you put heat sink compound on the module before you installed it. Do not use dialectic grease.
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smparr

smparr


Posts : 190
Join date : 2018-12-18
Location : Bremerton, Washington

1991 OCC TBI Coil Bad? Empty
PostSubject: Re: 1991 OCC TBI Coil Bad?   1991 OCC TBI Coil Bad? Icon_minitimeWed Jan 25, 2023 10:16 pm

Yes, I found a syringe of it at Best Buy. They call it thermal paste. I replaced the knock sensor a couple years ago. After I drove more today the ping was less but not gone.
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1991 OCC TBI Coil Bad? Empty
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