Running terrible, help
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The map made no difference. Ran a compression test and all were within 15 psi. Double checked plug gaps while they were out. I sprayed all the vac lines down with ether and found no leaks. Then I took it out and hammered on it and it runs noticeably better, but still not great. I am out of ideas. Going to drive it to work tomorrow and see how it goes.
Cargo Master
Joined: Jun 2013
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From: Somewhere n North America
Good luck - Those old computers like a good 10 mile run after adding new extremities or after being disconnected from power. Might run rough for the first mile or 10 minutes, which ever comes first. Remember the EECM is in charge....
What about the vacuum lines under the dash?
Answer all the un-answered questions on this thread, that's the way no hands on, remote backyard suggestions support works.
What about the vacuum lines under the dash?
Answer all the un-answered questions on this thread, that's the way no hands on, remote backyard suggestions support works.
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The vac lines under the dash are fine. When I did the compression test earlier I slipped and broke the little pie shaped valve/tee and it was still holding vac about 20 minutes after shut down. I sprayed all the vac lines and the intake with ether after reassembling also with no response.
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Not sure what you mean here, I have tried to answer as complete as possible. Is there info I have failed to provide? I'm not a mechanic, so there may be, that's why I'm looking for help to make my old junk function.
Cargo Master
Joined: Jun 2013
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From: Somewhere n North America
Post #12 - You mention the TPS, is your signal at closed throttle adjusted to spec?
Ok, maybe only 1 really....... good luck with the drive....
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The only tach I have is a borrowed digital timing light and the tps is adjusted to .97v and appeared to move smoothly through the throttle range. It got me to work just fine this morning but I still have a shake at idle and lack of power after all this. I have to be missing something.
Cargo Master
Joined: Jun 2013
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From: Somewhere n North America
FWIW -
" I sprayed all the vac lines down with ether and found no leaks." Don't like this....
I still say cap all your vacuum lines at the engine, and just hook up the MAP & FPR using new hose. This just eliminates any possibility of a hose related vacuum leak. Check under the TB for vacuum lines. You will need to add the Brake line if you're going to drive...
Shaking is pretty much the same as a steady miss, would you say?
Check ref voltage at the connector for the ECT & ACT, also check the resistance across the two pins on the sensors. Check from each pin to ground as well.
Speaking of; Have you verified the 5vdc reference output from the computer?
Something else that has come up is making sure the computer is getting 12V, and that the grounds are present.
" I sprayed all the vac lines down with ether and found no leaks." Don't like this....
I still say cap all your vacuum lines at the engine, and just hook up the MAP & FPR using new hose. This just eliminates any possibility of a hose related vacuum leak. Check under the TB for vacuum lines. You will need to add the Brake line if you're going to drive...
Shaking is pretty much the same as a steady miss, would you say?
Check ref voltage at the connector for the ECT & ACT, also check the resistance across the two pins on the sensors. Check from each pin to ground as well.
Speaking of; Have you verified the 5vdc reference output from the computer?
Something else that has come up is making sure the computer is getting 12V, and that the grounds are present.
Last edited by vjsimone; Mar 4, 2017 at 11:12 PM. Reason: Correcting text
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I watched the timing advance with the light when revved. I did check for 5v at the map sensor, but I have not checked the computer directly for 12 volts. I do have a good ground from firewall to engine although the one underneath the cab is attached to rust. I did check ect and act for a short, but not for voltage.
The egr is disconnected from exhaust and there's a plate between valve and intake.
Also I would agree it's a steady miss and I have disconnected all of the vac lines looking for a change, but only for a short time. I will cap them all and drive it when I get home from work this morning.
The egr is disconnected from exhaust and there's a plate between valve and intake.
Also I would agree it's a steady miss and I have disconnected all of the vac lines looking for a change, but only for a short time. I will cap them all and drive it when I get home from work this morning.
Cargo Master
Joined: Jun 2013
Posts: 3,176
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From: Somewhere n North America
With 5v at the MAP, your ref voltage from the EECM is good. You should get the same 5v at the single wire OBD STI test connector.
@ About 75degF, those 2 sensors (ACT/ECT) are about 35K ohms across the 2 pins. Higher the temp, lower the resistance. Maybe about 2.5 vdc ref voltage at the connector pins to these 2 (could be 1-4 v).
There have been past issues with power and ground to the EECM, just another thing to check and eliminate. EECM Pin # 57 is a good spot to check for 12v. I believe there is a ground connector at the battery & a ground on the back top of the block.
Just a note, keep the MAP & FPR hooked up separately, but you need a piece of new line for that. I like to hook up my vacuum gage as well, with these 3 hooked into the manafold tree, fewer pipes to cap.... also, keep an eye open for vac lines under the TB.
Blocking of the EGR is a good thing, especially when troubleshooting. Also running high-test while troubleshooting eliminates low octane issues.
@ About 75degF, those 2 sensors (ACT/ECT) are about 35K ohms across the 2 pins. Higher the temp, lower the resistance. Maybe about 2.5 vdc ref voltage at the connector pins to these 2 (could be 1-4 v).
There have been past issues with power and ground to the EECM, just another thing to check and eliminate. EECM Pin # 57 is a good spot to check for 12v. I believe there is a ground connector at the battery & a ground on the back top of the block.
Just a note, keep the MAP & FPR hooked up separately, but you need a piece of new line for that. I like to hook up my vacuum gage as well, with these 3 hooked into the manafold tree, fewer pipes to cap.... also, keep an eye open for vac lines under the TB.
Blocking of the EGR is a good thing, especially when troubleshooting. Also running high-test while troubleshooting eliminates low octane issues.
Last edited by vjsimone; Mar 5, 2017 at 10:10 AM. Reason: Adding text
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