Possible Bad Gas?
08-07-2005, 10:47 PM
#1
Launching!
Thread Starter
Possible Bad Gas? Hello
1997 Z28 M6
I was on a roadtrip today.
On the last leg of the trip, I filled up ~1/2 tank at a amoco gas station (87 octane). Some miles later, I go to pass someone, and as soon as the car hit ~3500rpm, it started surging and (felt like nasty misses).
After traffic opened up some, I slowed down, and tried to rev it up again. Regardless of what gear I'm in (even 1st), at 3500+, it's doing it).
I'm pretty sure its related to this gas because earlier in the day I was running the car pretty hard, especially when passing people, and it easily revved to 5K with no surging.
Can bad gas manifest itself at higher rpms (and obviously higher loads) only?
When it was surging, no SES light came on. The car idles fine, starts right up, etc. Low rpm drivability is normal.
Any help would be appreciated. It's a scary feeling to try to pass someone on a 2 lane country road and have the car buck at you.
1997 Z28 M6
I was on a roadtrip today.
On the last leg of the trip, I filled up ~1/2 tank at a amoco gas station (87 octane). Some miles later, I go to pass someone, and as soon as the car hit ~3500rpm, it started surging and (felt like nasty misses).
After traffic opened up some, I slowed down, and tried to rev it up again. Regardless of what gear I'm in (even 1st), at 3500+, it's doing it).
I'm pretty sure its related to this gas because earlier in the day I was running the car pretty hard, especially when passing people, and it easily revved to 5K with no surging.
Can bad gas manifest itself at higher rpms (and obviously higher loads) only?
When it was surging, no SES light came on. The car idles fine, starts right up, etc. Low rpm drivability is normal.
Any help would be appreciated. It's a scary feeling to try to pass someone on a 2 lane country road and have the car buck at you.
08-08-2005, 01:44 PM
#5
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If you do have some sort of crap in your gas tank, it might be able to significantly block gas flow while attempting to pass, even though you replaced that filter last October. Possible tune-up might be inorder? Plugs, wires (check to see none are grounded/worn), PCV valve, etc. Guess an injector could be plugged.
I don't know 100th of what some of these more intelligent LS1 owners do, so maybe someone else can add/correct here?
Good luck to you.
Steve
I don't know 100th of what some of these more intelligent LS1 owners do, so maybe someone else can add/correct here?
Good luck to you.
Steve
08-08-2005, 04:55 PM
#6
Launching!
Thread Starter
I brought it over to a shop where a friend works. He took it around the block a few times. The problem did not surface for him at all.
Some time later I take the car home... Get ~a mile or so away from the shop, this time its doing it at ever lower rpms (like 1000-2000), and very sporadically.
I left the car there for him to take home with while his scan tool is connected. He says he can record key parameters if/while its doing it, to get some idea if its fuel or ignition related.
The car did have a complete tune up last fall incl water pump, hoses, plugs, wires, cap/rotor & optispark and other misc things.
In fact, the first optispark unit failed and was replaced a month afterwards. No issues until now [assuming its ignition related] with the 2nd unit.
We did take a sample of gas from the fuel rail, and it appeared clean.
The car is in need of an intake gasket and valve cover gaskets, so that will be done at the same time.
Some time later I take the car home... Get ~a mile or so away from the shop, this time its doing it at ever lower rpms (like 1000-2000), and very sporadically.
I left the car there for him to take home with while his scan tool is connected. He says he can record key parameters if/while its doing it, to get some idea if its fuel or ignition related.
The car did have a complete tune up last fall incl water pump, hoses, plugs, wires, cap/rotor & optispark and other misc things.
In fact, the first optispark unit failed and was replaced a month afterwards. No issues until now [assuming its ignition related] with the 2nd unit.
We did take a sample of gas from the fuel rail, and it appeared clean.
The car is in need of an intake gasket and valve cover gaskets, so that will be done at the same time.
08-10-2005, 09:47 AM
#7
Launching!
Thread Starter
Small update.
My friend was finally able to experience the problem, and a code did get set. 1371 .
According to him, it's an optispark failure.
The unit on the car is the 2nd one. The original replacement was done as part of the tune up last fall. A month later, the car stalled out on the highway and it was replaced again. It worked fine until now.
Probably coincidental that it started acting up right after a fillup.
Got a brand new oem on order, should be here tomorrow, and hopefully installed by friday.
For now, the car seems to be ok when cool/cold, but after it reaches operating temps, it starts acting up (even at lower rpm), with any type of low to moderate load.
Almost seems like heat is causing the opti to fail.
My friend was finally able to experience the problem, and a code did get set. 1371 .
According to him, it's an optispark failure.
The unit on the car is the 2nd one. The original replacement was done as part of the tune up last fall. A month later, the car stalled out on the highway and it was replaced again. It worked fine until now.
Probably coincidental that it started acting up right after a fillup.
Got a brand new oem on order, should be here tomorrow, and hopefully installed by friday.
For now, the car seems to be ok when cool/cold, but after it reaches operating temps, it starts acting up (even at lower rpm), with any type of low to moderate load.
Almost seems like heat is causing the opti to fail.
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08-19-2005, 03:58 PM
#8
Launching!
Thread Starter
UPDATE:
Got the car back this afternoon.
It was indeed the optispark taking a crap again.
A new GM optispark was installed (good price from VanDevere Buick/Pontiac/Olds, Akron, OH -- http://shbox.com/1/4th_gen_tech2.html#Dal_and_Jason ).
In addition, unrelated (I'm pretty sure), the intake gasket was starting to seep pretty bad, so that got relaced & repaired as well.
The car revs up without any hesitation now. We both test drove it, and even when hot, it still revs properly.
It even seems to rev up easier than before (ie when downshifting).. Probably in my head, but who knows.
Hopefully this will be the last optispark to get installed in this car... At least while I'm the owner. This will be #4.
Got the car back this afternoon.
It was indeed the optispark taking a crap again.
A new GM optispark was installed (good price from VanDevere Buick/Pontiac/Olds, Akron, OH -- http://shbox.com/1/4th_gen_tech2.html#Dal_and_Jason ).
In addition, unrelated (I'm pretty sure), the intake gasket was starting to seep pretty bad, so that got relaced & repaired as well.
The car revs up without any hesitation now. We both test drove it, and even when hot, it still revs properly.
It even seems to rev up easier than before (ie when downshifting).. Probably in my head, but who knows.
Hopefully this will be the last optispark to get installed in this car... At least while I'm the owner. This will be #4.
09-13-2005, 04:53 PM
#10
Launching!
Thread Starter
Looks like the gremlins are back to attack.
Was leaving to do some errands today, a few min after starting the car, it hesitated, then SES came on.
After scanning it later, a p0100 (MAF failure), and P1371 (too few pulses) were recorded.
Several restarts later, the SES light went out. I also cleared the history, (in that order), but we'll see if it returns.
Was leaving to do some errands today, a few min after starting the car, it hesitated, then SES came on.
After scanning it later, a p0100 (MAF failure), and P1371 (too few pulses) were recorded.
Several restarts later, the SES light went out. I also cleared the history, (in that order), but we'll see if it returns.
