Rough after tune up
Thread Starter
Advanced
Joined: Feb 2008
Posts: 75
Likes: 0
From: Encinitas (San Diego) CA
Rough after tune up
I just replace the plugs, wires, O2 sensors, fuel filter, and PCV valve on my 94 LT1.
The car now runs very rough, even at very low speed and rpm.
I removed every wire and plug and tested. I had a bad one, probably from a drop, I replace it and now each one sparks.
The car ran fine before I did this work. So I believe it must be something I did wrong.
I may be wrong but swapping fuel filter and O2 sensors shouldn't cause this rough idle. So I think its the plugs.
I think the gap on a n94 LT1 should be .05. If the gap is off will it cause the idle to be so rough? I searched and I did find posts where gap had impact but the problem was at higher RPMs.
Any ideas??
The car now runs very rough, even at very low speed and rpm.
I removed every wire and plug and tested. I had a bad one, probably from a drop, I replace it and now each one sparks.
The car ran fine before I did this work. So I believe it must be something I did wrong.
I may be wrong but swapping fuel filter and O2 sensors shouldn't cause this rough idle. So I think its the plugs.
I think the gap on a n94 LT1 should be .05. If the gap is off will it cause the idle to be so rough? I searched and I did find posts where gap had impact but the problem was at higher RPMs.
Any ideas??
Thread Starter
Advanced
Joined: Feb 2008
Posts: 75
Likes: 0
From: Encinitas (San Diego) CA
i can't see any hoses undone.
Just check a plug and the gap is .045 and the info sheet on under the hood says it should be .050.
I'll have to adjust each one. .005 can make that much difference, small size does matter.
Just check a plug and the gap is .045 and the info sheet on under the hood says it should be .050.
I'll have to adjust each one. .005 can make that much difference, small size does matter.
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
are the ignition wires fully inserted on the plugs and in the Opti?
whats the resistance of the wires?
what brand O2 sensors? (they can cause crappy running once car gets into closed loop) does the car run good at first and get worse as it warms up?
Did you get crap in the fuel lines when you changed the filter and clog an injector?
You are living the reason I try to only mess with one thing at a time. Quality control seems to be spotty with replacement parts (even alleged high quality brands) so I try to only mess with one system at a time so that its easy to backtrack.
Good luck!
Mike
Last edited by aboatguy; May 30, 2008 at 03:43 PM.
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Thread Starter
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Joined: Feb 2008
Posts: 75
Likes: 0
From: Encinitas (San Diego) CA
Mike,
I so agree with you now. The three most important lessens for this newbie,
1) If it ain't broke don't fix it.
2) If you feel like working on the car for the weekend, see rule 1.
3) Like Mike said, One Thing At A time.
Got it running. I had the number 7 wire and the number 1 wires backwards on the Opti. When I checked it the first time it seemed correct, must have been getting tired or got lost feeling around that little area.
Anyway, she is running like a champ. Now I can put on those new bilsteins that came in today! And have a very cold beer
Thanks to everyone for the help.
This site is awesome
I so agree with you now. The three most important lessens for this newbie,
1) If it ain't broke don't fix it.
2) If you feel like working on the car for the weekend, see rule 1.
3) Like Mike said, One Thing At A time.
Got it running. I had the number 7 wire and the number 1 wires backwards on the Opti. When I checked it the first time it seemed correct, must have been getting tired or got lost feeling around that little area.
Anyway, she is running like a champ. Now I can put on those new bilsteins that came in today! And have a very cold beer
Thanks to everyone for the help.
This site is awesome
Drifting
Joined: Jul 2007
Posts: 1,294
Likes: 37
Been there
After my hot cam install, I swore that I had put the wires in correctly. I even thought I'd double check it. However, on the Lt-1, if you think you can accurately trace the wires coming off the opti to the cylinder heads, you would be wrong.
My car was running a little rough, but everything seemed normal until I tried to drive it under load. Checked vacuum...normal. I got under the car and traced the wires. Viola! crossed wires!
My money is on crossed wires.
My car was running a little rough, but everything seemed normal until I tried to drive it under load. Checked vacuum...normal. I got under the car and traced the wires. Viola! crossed wires!
My money is on crossed wires.
