2000 z28. HELP!!!!!!
Thread Starter
Teching In
Joined: Apr 2011
Posts: 8
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2000 z28. HELP!!!!!! So who wants to be the guru that can finally figure out what's wrong with my car, so far i have everyone I've spoken to completely stumped. 2000 z28 m6, torquer v2 cam, all supporting internals, intake, exhaust, and tune. All work was done 2 years ago, problem started last fall before storage.
Between idle and 2500 rpm the car will buck, sputter, and drive like compete ****. After a short while of driving (5 mins or so) it'll want to stall from a stop as well, i have to ride the clutch at 3k rpm to get it moving. Anything over 2500 rpm is perfectly smooth driving though. I have hpt logs of the problem occurring too.
I have replaced plugs, fuel filter, map sensor, drivers side o2 (passenger won't come out but read as expected). As well as tested fuel pump (no less than 55psi at WOT). Also ran it with MAF unplugged, same exact symptoms. Uploaded an Open Loop version of my tune, no difference in any way.
If anyone can help and get her back to being drivable, i will forever be in your debt. Feel free to ask any questions. I'll provide any and all info that i can.
Between idle and 2500 rpm the car will buck, sputter, and drive like compete ****. After a short while of driving (5 mins or so) it'll want to stall from a stop as well, i have to ride the clutch at 3k rpm to get it moving. Anything over 2500 rpm is perfectly smooth driving though. I have hpt logs of the problem occurring too.
I have replaced plugs, fuel filter, map sensor, drivers side o2 (passenger won't come out but read as expected). As well as tested fuel pump (no less than 55psi at WOT). Also ran it with MAF unplugged, same exact symptoms. Uploaded an Open Loop version of my tune, no difference in any way.
If anyone can help and get her back to being drivable, i will forever be in your debt. Feel free to ask any questions. I'll provide any and all info that i can.
Last edited by loud2000z28; May 5, 2015 at 06:11 PM. Reason: more info
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So who wants to be the guru that can finally figure out what's wrong with my car, so far i have everyone I've spoken to completely stumped. 2000 z28 m6, torquer v2 cam, all supporting internals, intake, exhaust, and tune. All work was done 2 years ago, problem started last fall before storage.
Between idle and 2500 rpm the car will buck, sputter, and drive like compete ****. After a short while of driving (5 mins or so) it'll want to stall from a stop as well, i have to ride the clutch at 3k rpm to get it moving. Anything over 2500 rpm is perfectly smooth driving though. I have hpt logs of the problem occurring too.
I have replaced plugs, fuel filter, map sensor, drivers side o2 (passenger won't come out but read as expected). As well as tested fuel pump (no less than 55psi at WOT). Also ran it with MAF unplugged, same exact symptoms. Uploaded an Open Loop version of my tune, no difference in any way.
If anyone can help and get her back to being drivable, i will forever be in your debt. Feel free to ask any questions. I'll provide any and all info that i can.
Between idle and 2500 rpm the car will buck, sputter, and drive like compete ****. After a short while of driving (5 mins or so) it'll want to stall from a stop as well, i have to ride the clutch at 3k rpm to get it moving. Anything over 2500 rpm is perfectly smooth driving though. I have hpt logs of the problem occurring too.
I have replaced plugs, fuel filter, map sensor, drivers side o2 (passenger won't come out but read as expected). As well as tested fuel pump (no less than 55psi at WOT). Also ran it with MAF unplugged, same exact symptoms. Uploaded an Open Loop version of my tune, no difference in any way.
If anyone can help and get her back to being drivable, i will forever be in your debt. Feel free to ask any questions. I'll provide any and all info that i can.
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Thread Starter
Teching In
Joined: Apr 2011
Posts: 8
Likes: 0
Sorry i took so long to answer.
Havent checked compression yet, its on the to do list when i get some time off of work.
The problem existed before storage.
Drained the tank and replaced with new gas.
Guess the logs didn't attach, my bad. Will put them on when i get home.
Wires are good, don't have spare coils to check with.
Injectors are 42.5# from speedinc with about 25k miles on them.
I'll double check this and make sure i touched on all of your replies shortly.
Thanks for the help thus far.
Havent checked compression yet, its on the to do list when i get some time off of work.
The problem existed before storage.
Drained the tank and replaced with new gas.
Guess the logs didn't attach, my bad. Will put them on when i get home.
Wires are good, don't have spare coils to check with.
Injectors are 42.5# from speedinc with about 25k miles on them.
I'll double check this and make sure i touched on all of your replies shortly.
Thanks for the help thus far.
Thread Starter
Teching In
Joined: Apr 2011
Posts: 8
Likes: 0
So i took it to a shop to diagnose the problem. They cant come to a definitive cause for the problem. But they did note that there are issues with the MAP, MAF, and IAC. I guess ill get those figured out and see what happens.
I just find it odd that all three sensors just come up out of nowhere with issues.
Anybody think there is a potential of a computer gone bad?
I just find it odd that all three sensors just come up out of nowhere with issues.
Anybody think there is a potential of a computer gone bad?
The data on all of those sensors will appear skewed if the pcm is fighting a problem and trying to correct. You need a knowledgeable LS performance shop to go over it and the tune.
So i took it to a shop to diagnose the problem. They cant come to a definitive cause for the problem. But they did note that there are issues with the MAP, MAF, and IAC. I guess ill get those figured out and see what happens.
I just find it odd that all three sensors just come up out of nowhere with issues.
Anybody think there is a potential of a computer gone bad?
I just find it odd that all three sensors just come up out of nowhere with issues.
Anybody think there is a potential of a computer gone bad?
You changed out almost everything else....might as well get a new TPS sensor too....
.
Banned
Joined: Apr 2015
Posts: 9
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Could be wrong....but sometimes when you see problems with all of those sensors.....its a worn out TPS sensor sending bad info to the PCM. The TPS will get worn out in the area of the most used rpm range.....and then give you problems in that rpm range.
You changed out almost everything else....might as well get a new TPS sensor too....
.
You changed out almost everything else....might as well get a new TPS sensor too....
.
Thread Starter
Teching In
Joined: Apr 2011
Posts: 8
Likes: 0
Finally figured out what the problem was, or at least most of it. Turns out when the headers were installed by the previous owner, they never allowed enough clearance between the header and the power wire to the starter as well as the ground wire in the same location. The header burned through the wireloom and sheathing on the wires, causing them to ground out to the header.
Im assuming the rpm related aspect of it was when the motor torqued enough to open a gap between the header and the wires. I have to go and replace a section of the wires and reroute to a safer location. I wrapped the wires and pulled them away from the header temporarily and it drives considerably better, though still shows the same issue at times. Now to finish up the fix and hope all goes back to normal.
I appreciate all of the attempts at trying to figure this out.
Im assuming the rpm related aspect of it was when the motor torqued enough to open a gap between the header and the wires. I have to go and replace a section of the wires and reroute to a safer location. I wrapped the wires and pulled them away from the header temporarily and it drives considerably better, though still shows the same issue at times. Now to finish up the fix and hope all goes back to normal.
I appreciate all of the attempts at trying to figure this out.