Engine issue....please help
March 11th, 2012, 06:29 PM
#1
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Join Date: Dec 2011
Posts: 16
Engine issue....please help
Greetings all....I have a 1987 Delta 88 with a problem I cannot diagnose. No codes come up on the computer scan. Between 45 and 55 miles per hour, the motor will jerk real hard, like the transmission is shifting hard. Had the tranny checked and there are no issues. Anybody have any info.....Many thanks
March 11th, 2012, 07:44 PM
#4
My dodge does that same thing. lock up engages too soon and motor jerks shakes etc. I just bypassed the tps with a potentiometer but my dodge is an older mechanical diesel dunno. You might just need a tps sensor .
March 11th, 2012, 08:09 PM
#8
yes the tps sensor on my dodge was bypased so when it hits a certain point thats when the lock up hits. I have it set to 45 ish 50. Dunno if it can be done on newer cars my dodge is a 94. It's a common kit for first and second gen dodge cummins trucks with tps sensors offer through high perf diesel shops. It's not hooked up to the throttle at all some how it still down shifts. I know the dodge and this car are diffrent but when my tps sensor was bad thats what it did.
Last edited by coppercutlass; March 11th, 2012 at 08:15 PM.
March 14th, 2012, 09:53 AM
#9
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,258
I'm going to disagree here. Yes, it's possible for the solenoid to go bad, but the jerking you describe has led to the replacement of more good solenoids than anything else. The real problem is that when the solenoid locks up, any misfire in the engine is felt as a jerking in the drivetrain (just like in a manual trans car). If there are no codes set, the most likely problem is ignition. I had exactly this problem on a similar vintage GM car, and the problem (and misfire that caused it) went away when I replaced the ignition coils and module. Note that a bad coil or ignition module won't set a code.
March 25th, 2012, 07:28 AM
#11
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Reply
I'm going to disagree here. Yes, it's possible for the solenoid to go bad, but the jerking you describe has led to the replacement of more good solenoids than anything else. The real problem is that when the solenoid locks up, any misfire in the engine is felt as a jerking in the drivetrain (just like in a manual trans car). If there are no codes set, the most likely problem is ignition. I had exactly this problem on a similar vintage GM car, and the problem (and misfire that caused it) went away when I replaced the ignition coils and module. Note that a bad coil or ignition module won't set a code.
March 25th, 2012, 07:30 AM
#12
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Posts: 16
The coils have been tested and they are good.....I replaced the ignition module and the car started once and died. Now it will not start with the new module at all. Is there some trick to the installation? Many thanks for your reply
March 25th, 2012, 01:03 PM
#16
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Join Date: Sep 2010
Location: The Hudson Valley
Posts: 21,183
If the HEI module came with white heat sink paste, remove the module, open the tiny package, squeeze out the paste onto the bottom of the module, spread it evenly on the whole bottom, then put it back together.
If it came with clear, slippery stuff, then throw the clear stuff out, go to Radio Shack, buy a tube of heat sink paste, and smear it on the bottom of the module as above.
- Eric
If it came with clear, slippery stuff, then throw the clear stuff out, go to Radio Shack, buy a tube of heat sink paste, and smear it on the bottom of the module as above.
- Eric
March 25th, 2012, 02:03 PM
#17
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Thread Starter
Join Date: Dec 2011
Posts: 16
If the HEI module came with white heat sink paste, remove the module, open the tiny package, squeeze out the paste onto the bottom of the module, spread it evenly on the whole bottom, then put it back together.
If it came with clear, slippery stuff, then throw the clear stuff out, go to Radio Shack, buy a tube of heat sink paste, and smear it on the bottom of the module as above.
- Eric
If it came with clear, slippery stuff, then throw the clear stuff out, go to Radio Shack, buy a tube of heat sink paste, and smear it on the bottom of the module as above.
- Eric
March 25th, 2012, 03:20 PM
#19
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Join Date: Sep 2010
Location: The Hudson Valley
Posts: 21,183
The heat paste will not make the car run - it will prevent the module from burning out and stranding you.
I'm sorry that I didn't understand that you thought that.
The car isn't running because of something you did when you changed the module.
You need to slowly go through everything you did, and recheck every step.
Likely problems include one or both wires from the sensor pinched under the module or the vacuum diaphragm mount and poorly connected or corroded wires.
You should verify that you have 12V at the hot wire into the distributor.
Finally, you may have a bad module out of the box.
I bought one last week - had the store test the old one, it failed, had them test the new one, it failed, too. As they only had one, I had to go to another store to get one.
You can bet that I had them test that one, too, before I bought it.
- Eric
I'm sorry that I didn't understand that you thought that.
The car isn't running because of something you did when you changed the module.
You need to slowly go through everything you did, and recheck every step.
Likely problems include one or both wires from the sensor pinched under the module or the vacuum diaphragm mount and poorly connected or corroded wires.
You should verify that you have 12V at the hot wire into the distributor.
Finally, you may have a bad module out of the box.
I bought one last week - had the store test the old one, it failed, had them test the new one, it failed, too. As they only had one, I had to go to another store to get one.
You can bet that I had them test that one, too, before I bought it.
- Eric
March 31st, 2012, 10:32 AM
#20
Registered User
Thread Starter
Join Date: Dec 2011
Posts: 16
The heat paste will not make the car run - it will prevent the module from burning out and stranding you.
I'm sorry that I didn't understand that you thought that.
The car isn't running because of something you did when you changed the module.
You need to slowly go through everything you did, and recheck every step.
Likely problems include one or both wires from the sensor pinched under the module or the vacuum diaphragm mount and poorly connected or corroded wires.
You should verify that you have 12V at the hot wire into the distributor.
Finally, you may have a bad module out of the box.
I bought one last week - had the store test the old one, it failed, had them test the new one, it failed, too. As they only had one, I had to go to another store to get one.
You can bet that I had them test that one, too, before I bought it.
- Eric
I'm sorry that I didn't understand that you thought that.
The car isn't running because of something you did when you changed the module.
You need to slowly go through everything you did, and recheck every step.
Likely problems include one or both wires from the sensor pinched under the module or the vacuum diaphragm mount and poorly connected or corroded wires.
You should verify that you have 12V at the hot wire into the distributor.
Finally, you may have a bad module out of the box.
I bought one last week - had the store test the old one, it failed, had them test the new one, it failed, too. As they only had one, I had to go to another store to get one.
You can bet that I had them test that one, too, before I bought it.
- Eric
March 31st, 2012, 12:23 PM
#21
Connoisseur d'Junque
Join Date: Sep 2010
Location: The Hudson Valley
Posts: 21,183
Ahhhhh... A mystery!
Well, first, never say never. They all could be bad.
Did you have them tested at the auto parts store?
Second, at this perplexing point, it would be beneficial if we could see some photographs of your situation. When things are behaving this badly, it is often helpful to have "another set of eyes" to look at what you;re doing, as there may be something simple that you're just not seeing.
Third, you need to be sure that nothing is touching anything that it's not supposed to be touching, that all wires are intact, with no breaks in the insulation, and that the connectors in all plugs are clean, tight, and making good contact.
Don't discount the possibility that the problem could actually be with the pickup.
Once you've done all that, get those modules checked.
- Eric
Well, first, never say never. They all could be bad.
Did you have them tested at the auto parts store?
Second, at this perplexing point, it would be beneficial if we could see some photographs of your situation. When things are behaving this badly, it is often helpful to have "another set of eyes" to look at what you;re doing, as there may be something simple that you're just not seeing.
Third, you need to be sure that nothing is touching anything that it's not supposed to be touching, that all wires are intact, with no breaks in the insulation, and that the connectors in all plugs are clean, tight, and making good contact.
Don't discount the possibility that the problem could actually be with the pickup.
Once you've done all that, get those modules checked.
- Eric
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