LS1 barely runs, unusual circumstances. Need serious wisdom here. Where do I start?
12-10-2012, 03:37 AM
#1
Staging Lane
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LS1 barely runs, unusual circumstances. Need serious wisdom here. Where do I start? I sold my 99Z M6 about a year ago. I loved this car, I almost cried when I saw it like this. It got destroyed by the new owner... I bought it back for a $1000. I sold the car originally with these bolt ons...
Ported FAST Intake 90mm, FAST TB 92mm, new plugs and wires, SLP lid, Pacesetter LT's no cats, TSP True Dual w/ Mufflex race mufflers, new TPS, emission delete, new o2 sensors and extensions, new fuel filter. 98,000 miles. STOCK TUNE!!! I repeat no tune... The car ran fine though, needed a tune obviously, but I went FRM, and sold it. Never had a problem like this when I had it.
Okay, well now that I have it back... It will not run right. I drove it 200 miles like this so hopefully that's a good sign. Here's what it's doing... As soon as I turn the key it revs to about 2500rpm. After 1 second (literally) with no driver input, the engine loses all power and shuts off. Like the ignition/fuel just turned off, and dies. However, I can keep it running with a little foot feed action. It misses terribly when I'm keeping it running like this though. It misses A LOT... The rpm's jump around too while I keep it going, it might stay at 1800rpm for 2 seconds then die, or rev to 4000rpm, then die. Without me touching the gas, its dies instantly. With a little courage I drove it like this. However, above about 2000rpm with a load, the car "runs" decent. Some sputter around 2000rpm, but no missing. WOT, it runs decent too, pulls okay still. Confusing already for me... While driving fine on the interstate, if at any time I push the clutch in, or put in neutral without hitting the gas, it will die, immediately. So while driving 60mph in 5th gear, running decently with cruise, push in the clutch or put it in neutral, the car dies withing 2 seconds, literally. Its ran like this for about a month he said. One day he just got in it and it started doing this. He said it sounded like a cammed idle for two days, then this, no idle ****. Good news, no knocking, and not much smoke that I can see really. It always does this, never changes. Not when it's warm out, cold out, warmed up car, cold start etc...
So after digging a little... The o2 extensions are shredded. Which shouldn't make it die immediately. I unpluggged the MAF and it idles at about 3000rpm, with no missing. Cleaned the MAF, no help. Unplugged all the sensors that didn't change anything. Tried to check for vacuum leaks, but it wont idle, and it's very, very loud. I don't see any fuel leaks. Getting a fuel pressure gauge tomorrow, let you know what that is. I can hear the fuel pump prime.
I don't know where to start. It still has no tune, and the o2 sensors are not hooked up/ working. The MAF is stock. Fuel Pump is stock, 100,000 miles now. I don't understand why it will run WOT, but not even idle for 3 seconds. I don't know what to look for for codes, cause its going to throw a bunch already like this.
Please, someone help me. I sold this car after a bad breakup, regretted it for a year. Now I got over the b**** and bought it back. I can't not love this car. Any wisdom will help.
Ported FAST Intake 90mm, FAST TB 92mm, new plugs and wires, SLP lid, Pacesetter LT's no cats, TSP True Dual w/ Mufflex race mufflers, new TPS, emission delete, new o2 sensors and extensions, new fuel filter. 98,000 miles. STOCK TUNE!!! I repeat no tune... The car ran fine though, needed a tune obviously, but I went FRM, and sold it. Never had a problem like this when I had it.
Okay, well now that I have it back... It will not run right. I drove it 200 miles like this so hopefully that's a good sign. Here's what it's doing... As soon as I turn the key it revs to about 2500rpm. After 1 second (literally) with no driver input, the engine loses all power and shuts off. Like the ignition/fuel just turned off, and dies. However, I can keep it running with a little foot feed action. It misses terribly when I'm keeping it running like this though. It misses A LOT... The rpm's jump around too while I keep it going, it might stay at 1800rpm for 2 seconds then die, or rev to 4000rpm, then die. Without me touching the gas, its dies instantly. With a little courage I drove it like this. However, above about 2000rpm with a load, the car "runs" decent. Some sputter around 2000rpm, but no missing. WOT, it runs decent too, pulls okay still. Confusing already for me... While driving fine on the interstate, if at any time I push the clutch in, or put in neutral without hitting the gas, it will die, immediately. So while driving 60mph in 5th gear, running decently with cruise, push in the clutch or put it in neutral, the car dies withing 2 seconds, literally. Its ran like this for about a month he said. One day he just got in it and it started doing this. He said it sounded like a cammed idle for two days, then this, no idle ****. Good news, no knocking, and not much smoke that I can see really. It always does this, never changes. Not when it's warm out, cold out, warmed up car, cold start etc...
So after digging a little... The o2 extensions are shredded. Which shouldn't make it die immediately. I unpluggged the MAF and it idles at about 3000rpm, with no missing. Cleaned the MAF, no help. Unplugged all the sensors that didn't change anything. Tried to check for vacuum leaks, but it wont idle, and it's very, very loud. I don't see any fuel leaks. Getting a fuel pressure gauge tomorrow, let you know what that is. I can hear the fuel pump prime.
I don't know where to start. It still has no tune, and the o2 sensors are not hooked up/ working. The MAF is stock. Fuel Pump is stock, 100,000 miles now. I don't understand why it will run WOT, but not even idle for 3 seconds. I don't know what to look for for codes, cause its going to throw a bunch already like this.
Please, someone help me. I sold this car after a bad breakup, regretted it for a year. Now I got over the b**** and bought it back. I can't not love this car. Any wisdom will help.
12-10-2012, 10:02 AM
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I ha problems like this except my car wouldn't die, the first thing you should fix is your O2 sensors on the manifolds. My bad O2 sensors made my car run like a civic no power or anything and after I floor it the motor would act like its running fine and just later misfire again. I pulled the heads off and one of the cylinder valves was pretty burnt up. So I would first replace your O2 sensors and check the wires for your MAF
12-10-2012, 08:48 PM
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Staging Lane
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Alright will do that first. However, will this change anything since the car is still on its stock tune with the bolt ons that I have? The wires to the MAF are good I'm assuming since when I unplugged it it idled, just really high.
12-10-2012, 09:49 PM
#4
The idle are control valve may be bad or stuck. Although I don't know if it can flow enough air for 2500 RPM.
The reason for it running fine without O2 sensors at WOT is that the O2's are not used. Only out of power enrichment are they used I believe. IE steady state and cruising.
Also with the O2 wires being shredded you really have no way of knowing what this did to your long term fuel trims. They could be WAY off. This is all verifiable with HPTuners or EFI live.
The reason for it running fine without O2 sensors at WOT is that the O2's are not used. Only out of power enrichment are they used I believe. IE steady state and cruising.
Also with the O2 wires being shredded you really have no way of knowing what this did to your long term fuel trims. They could be WAY off. This is all verifiable with HPTuners or EFI live.
12-11-2012, 02:26 PM
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Staging Lane
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The idle are control valve may be bad or stuck. Although I don't know if it can flow enough air for 2500 RPM.
The reason for it running fine without O2 sensors at WOT is that the O2's are not used. Only out of power enrichment are they used I believe. IE steady state and cruising.
Also with the O2 wires being shredded you really have no way of knowing what this did to your long term fuel trims. They could be WAY off. This is all verifiable with HPTuners or EFI live.
The reason for it running fine without O2 sensors at WOT is that the O2's are not used. Only out of power enrichment are they used I believe. IE steady state and cruising.
Also with the O2 wires being shredded you really have no way of knowing what this did to your long term fuel trims. They could be WAY off. This is all verifiable with HPTuners or EFI live.
12-13-2012, 01:33 AM
#7
Staging Lane
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Alright guys little update. Waiting for the o2 sensors to come in a friend stopped by a scanner. O2 sensors was one code, egr another, and MAP sensor was the other code. We also noticed that timing was jumping from 14 to 39 degrees while I was running it. Also had a misfire on cylinder 5. Friend drives 02SS, so I was able to eliminate MAF. IAC was dirty, still moved. Removed it, plugged it, unplugged it, ran the same every time. Backfires and smokes now, smell really rich.
The timing degrees seemed a bit extreme. Every time I blipped throttle to keep the car running it spiked over 35 degrees but yet fell to 14 degrees at points. Crank sensor..?
No clue on how a car acts with a bad map sensor...
The timing degrees seemed a bit extreme. Every time I blipped throttle to keep the car running it spiked over 35 degrees but yet fell to 14 degrees at points. Crank sensor..?
No clue on how a car acts with a bad map sensor...
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12-15-2012, 05:06 PM
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Staging Lane
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