C4 Corvette with LS 6.0L
Thread Starter
Teching In
Joined: Sep 2017
Posts: 34
Likes: 4
From: Edinboro, PA
C4 Corvette with LS 6.0L Hey guys,
So I am having an issue with my LS swap into my 1984 C4 Corvette. Actually, probably going to have many issues, it’s a terrible and long story. At the moment, the issue is that when I start the car it runs really poorly and stalls. Terrible idle. And if I give it throttle it hesitates, stumbles, and dies. I have two videos of the car running. The first is with me just starting the car, giving it zero attention other than the start.
the second video is of how it runs when I give it throttle.
I would greatly appreciate any help. I am sure you guys are probably going to want more information as well. But let’s start here, thank you.
So I am having an issue with my LS swap into my 1984 C4 Corvette. Actually, probably going to have many issues, it’s a terrible and long story. At the moment, the issue is that when I start the car it runs really poorly and stalls. Terrible idle. And if I give it throttle it hesitates, stumbles, and dies. I have two videos of the car running. The first is with me just starting the car, giving it zero attention other than the start.
the second video is of how it runs when I give it throttle.
I would greatly appreciate any help. I am sure you guys are probably going to want more information as well. But let’s start here, thank you.
Thread Starter
Teching In
Joined: Sep 2017
Posts: 34
Likes: 4
From: Edinboro, PA
Quick update for you guys...I replaced a coil wire that had been cut through or ripped or chewed, something. However the car still stalled. Slept on it, researched what I could. I ended up changing some of the vacuum line placement the shop had done and the results were much better. The car doesn’t die anymore at idle and sounds much better. The hesitation and stumble are still their under load, so I am sure there are more issues. For now, here’s a video of it running and the current issue.
As usual, your help is always greatly appreciated.
As usual, your help is always greatly appreciated.
TECH Senior Member
Joined: Jul 2009
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Likes: 661
If the exhaust. Smells rich, The you at the least need CO2 sensors. Some people might say drive it, they might clean themselves. Change the plugs. I’d do these two things first and then report back
The rev sounds like a down cylinder. Again, change the plugs and two new GM oxy sensors. See if this helps
The rev sounds like a down cylinder. Again, change the plugs and two new GM oxy sensors. See if this helps
Thread Starter
Teching In
Joined: Sep 2017
Posts: 34
Likes: 4
From: Edinboro, PA
If the exhaust. Smells rich, The you at the least need CO2 sensors. Some people might say drive it, they might clean themselves. Change the plugs. I’d do these two things first and then report back
The rev sounds like a down cylinder. Again, change the plugs and two new GM oxy sensors. See if this helps
The rev sounds like a down cylinder. Again, change the plugs and two new GM oxy sensors. See if this helps
Thread Starter
Teching In
Joined: Sep 2017
Posts: 34
Likes: 4
From: Edinboro, PA
This came out of a 2001 or 2002 (have the specifics somewhere) Silverado 2500 HD 4x4 with 120,000 miles. The truck was rear ended beyond repair. Truck started and ran before the engine was pulled.
Teching In
Joined: Jul 2017
Posts: 15
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From: Northeast Louisiana
One other thing you can do while it is running to make sure the MAF doesn’t have a major leak behind it or it or the wiring was damaged is to unplug it. I have seen a few go from running like crap to run great after unplugging the MAF.
If it starts running better you need to check to see what the problem is.
Also are you running stock exhaust manifolds or headers. The location of the O2 sensors can affect how it runs.
If vacuum has affected it that much I would look for move vacuum leaks and no rule out you may have a leak inside the car under the dash.
If it starts running better you need to check to see what the problem is.
Also are you running stock exhaust manifolds or headers. The location of the O2 sensors can affect how it runs.
If vacuum has affected it that much I would look for move vacuum leaks and no rule out you may have a leak inside the car under the dash.
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Verdad Gallardo Thread Starter
Teching In
Joined: Sep 2017
Posts: 34
Likes: 4
From: Edinboro, PA
One other thing you can do while it is running to make sure the MAF doesn’t have a major leak behind it or it or the wiring was damaged is to unplug it. I have seen a few go from running like crap to run great after unplugging the MAF.
If it starts running better you need to check to see what the problem is.
Also are you running stock exhaust manifolds or headers. The location of the O2 sensors can affect how it runs.
If vacuum has affected it that much I would look for move vacuum leaks and no rule out you may have a leak inside the car under the dash.
If it starts running better you need to check to see what the problem is.
Also are you running stock exhaust manifolds or headers. The location of the O2 sensors can affect how it runs.
If vacuum has affected it that much I would look for move vacuum leaks and no rule out you may have a leak inside the car under the dash.
I am running stock C5 short exhaust manifolds, so I figure the distance is fine for the o2 sensors. The o2 sensors are brand new with the swap.
I checked the fuel pressure and it seems to be fine, no issues.
I ran a live scan for data while it ran, checking different parameters. What I noticed was that the scan showed that the long term fuel trim on bank 1 was dumping fuel, whereas the other bank seems to be in a regular level.
I am thinking there is still some sort of vacuum leak but no idea where at. I have built a smoke machine to test the system but it keeps blowing a fuse at the moment. Lol, if it’s not one thing it’s another.
