Need help with potential converter problem/drivability issue
Need help with potential converter problem/drivability issue 2000 Camaro, lots of mods….drivability issue and performance issue-
Car was running fine, changed plugs, changed oil and filter, tranny fluid and filter, cleaned nitrous filter, new fuel filter, did front brake pads, polished out headlights…
Drove fine, had nitrous in the line (didn’t race anyone that night), shut the bottle and hit the button (ran hard for a second, then flooded with fuel), check-engine light came on, drove it for a few minutes to clear everything out, light went out, felt fine. Next day, too friend for a ride, ran weird, idled high, very unresponsive, rpm’s came up real slow (like an ultra tight converter or something)…tried it on and of the bottle, same response until above 5,000 rpm, then the rpm’s came up faster. When driving, car would accelerate on its own all the way to 45 mph or so and stay there (from a dead stop with no gas being applied), when shifting into neutral at 45 mph, the rpm’s would climb to 1500 or so, and then slowly fall. If you hit it on a 40-50 roll, it would accelerate slowly until 5-5500 rpm then it would pick up speed.
Here is what I have done (unsuccessfully) to address this problem:
Disconnected/reconnected battery after every change-
Replaced IAC with another IAC from a good running, same year Camaro
Cleaned IAC
Replaced TPS
Checked for intake leaks with carb cleaner (none found, no surging at all)
Autotap- no codes
Snap on scanner- no codes
Had friend rev engine to 1800 rpm or so, disconnected IAC (per mechanic friend), car was more drivable down low, did not want to idle high or go to 45 mph on its own, but still felt sluggish (again like a ultra tight converter)
Went to Livernois to have car re-tuned…used a brand new ECM, did the tuning, made good power (dyno pulls were at 70 mph and above) made 580 rwhp and 644 tque so engine is not damaged, and everything ran great on the dyno-
Test drove it and the exact same problem as before with drivability. Tried replacing Metco breather with standard oil cap, seemed to help lower the idle a little but no major difference. Put foot on brake and foot on gas…floored gas…rpm’s went to 1800 at WOT on the brake, did not go above 1800 rpm’s or spin tires. At this point I thought the converter was bad, drove back home and shipped it to P.I. for a check. Everything checked out fine, they are restalling and sending back to me this coming week.
Having mechanic check intake gaskets for possible leaks, do a compression test, and putting 3.42 gears in rear end, and sending computer back to Livernois for gear swap. I believe the computer is now set to not lock the converter at all until 3rd gear at about 50 mph.
I can’t figure out what to do next IF the converter comes back and doesn’t fix the drivability issue….any thoughts about what to do?
SDB
Car was running fine, changed plugs, changed oil and filter, tranny fluid and filter, cleaned nitrous filter, new fuel filter, did front brake pads, polished out headlights…
Drove fine, had nitrous in the line (didn’t race anyone that night), shut the bottle and hit the button (ran hard for a second, then flooded with fuel), check-engine light came on, drove it for a few minutes to clear everything out, light went out, felt fine. Next day, too friend for a ride, ran weird, idled high, very unresponsive, rpm’s came up real slow (like an ultra tight converter or something)…tried it on and of the bottle, same response until above 5,000 rpm, then the rpm’s came up faster. When driving, car would accelerate on its own all the way to 45 mph or so and stay there (from a dead stop with no gas being applied), when shifting into neutral at 45 mph, the rpm’s would climb to 1500 or so, and then slowly fall. If you hit it on a 40-50 roll, it would accelerate slowly until 5-5500 rpm then it would pick up speed.
Here is what I have done (unsuccessfully) to address this problem:
Disconnected/reconnected battery after every change-
Replaced IAC with another IAC from a good running, same year Camaro
Cleaned IAC
Replaced TPS
Checked for intake leaks with carb cleaner (none found, no surging at all)
Autotap- no codes
Snap on scanner- no codes
Had friend rev engine to 1800 rpm or so, disconnected IAC (per mechanic friend), car was more drivable down low, did not want to idle high or go to 45 mph on its own, but still felt sluggish (again like a ultra tight converter)
Went to Livernois to have car re-tuned…used a brand new ECM, did the tuning, made good power (dyno pulls were at 70 mph and above) made 580 rwhp and 644 tque so engine is not damaged, and everything ran great on the dyno-
Test drove it and the exact same problem as before with drivability. Tried replacing Metco breather with standard oil cap, seemed to help lower the idle a little but no major difference. Put foot on brake and foot on gas…floored gas…rpm’s went to 1800 at WOT on the brake, did not go above 1800 rpm’s or spin tires. At this point I thought the converter was bad, drove back home and shipped it to P.I. for a check. Everything checked out fine, they are restalling and sending back to me this coming week.
Having mechanic check intake gaskets for possible leaks, do a compression test, and putting 3.42 gears in rear end, and sending computer back to Livernois for gear swap. I believe the computer is now set to not lock the converter at all until 3rd gear at about 50 mph.
I can’t figure out what to do next IF the converter comes back and doesn’t fix the drivability issue….any thoughts about what to do?
SDB
Any chance of a nitrous backfire, blowing out a
safety plug, trashing the MAP sensor, or putting
a crack in the manifold somewhere you didn't
shoot the carb cleaner?
Scan the MAP sensor value, engine stopped should
be 100kPa and idling, maybe 30-35kPa? Those being
right, would probably rule out MAP sensor damage.
Get idling and then pull the IAC, and redo the vacuum
leak test with special attention to the back of the
intake manifold (or, hell, just fog the whole area with
an unlit propane torch, inch by inch?). Not just looking
for gasket leaks, but a crack that could be anywhere.
A cylinder-by-cylinder compression test might be in
order too.
But before all that, you might want to set up the
scanner for misfire-current counts on all 8 cylinders,
see what shows up there.
safety plug, trashing the MAP sensor, or putting
a crack in the manifold somewhere you didn't
shoot the carb cleaner?
Scan the MAP sensor value, engine stopped should
be 100kPa and idling, maybe 30-35kPa? Those being
right, would probably rule out MAP sensor damage.
Get idling and then pull the IAC, and redo the vacuum
leak test with special attention to the back of the
intake manifold (or, hell, just fog the whole area with
an unlit propane torch, inch by inch?). Not just looking
for gasket leaks, but a crack that could be anywhere.
A cylinder-by-cylinder compression test might be in
order too.
But before all that, you might want to set up the
scanner for misfire-current counts on all 8 cylinders,
see what shows up there.
I will be doing a compression test and possibly leak down test of all cylinders...
I am pulling intake to check for cracks and pinched gasket...
I will get the snapon scanner back on and drive the car looking at various counts...wouldnt this set a code though??
This is such an odd problem...hope its just a vacuum leak I couldn't find with the carb cleaner...piched gasket in back of intake could account for some of the issues
SDB
I am pulling intake to check for cracks and pinched gasket...
I will get the snapon scanner back on and drive the car looking at various counts...wouldnt this set a code though??
This is such an odd problem...hope its just a vacuum leak I couldn't find with the carb cleaner...piched gasket in back of intake could account for some of the issues
SDB
Gross misfires will set a code but what to look for,
when chasing a vacuum leak, is any -current misfires-
count on one cylinder that's out-of-bed with the rest.
This may clue you into a single-runner vacuum leak,
a spark plug that got fouled / tip trashed / wire off,
or whatever. If you see all cylinders at 0-10 and one
at 100 you sure know where to concentrate.
when chasing a vacuum leak, is any -current misfires-
count on one cylinder that's out-of-bed with the rest.
This may clue you into a single-runner vacuum leak,
a spark plug that got fouled / tip trashed / wire off,
or whatever. If you see all cylinders at 0-10 and one
at 100 you sure know where to concentrate.
