LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Strange problem HELP!!!!!!

Old Apr 27, 2003 | 04:18 PM
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Strange problem HELP!!!!!!

I installed cam, roller rockers, pushrods, opti, valve springs, and pcmforless PCM and got the car back running again a few days ago.... Ran pretty good for the first couple days, didnt really push it too hard, just driving around town and such, got on it a couple times... Well last night an O2 sensor wire shorted out on the header and blew my engine sensor fuse... I fixed that problem, re routed the wiring and rewrapped it... Well last night the car was driving really bad when the fuse blew... and now, even though I think I have fixed the problem, the car tries to idle at 2000 or so rpm if I drive it.. But when I first crank it, she idles like normal. its only after driving that it begins to act weird. Anyone have any suggestions?? Im drawing a blank on what could be causing the problem Thanks in advance for any insight yall may have.
Old Apr 27, 2003 | 08:22 PM
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I rewired my O2 extenders thinking maybe a wire was crossed causing it to want to rev to 2000 rpm and stay up there... I rewired everything, reset the PCM again, and still the same problem, although the car does seem to idle better before I take it over 2000, but once revs go over 2000 they dont want to come back down, and the car just runs really rough below 2000. Im getting really frustrated does anyone have any ideas at all? The car is driving me crazy Would a bad intake manifold seal cause this? I dont want to pull the intake manifold off and reseal everything only to have it not solve the problem... Anyone have any ideas??
Old Apr 27, 2003 | 08:31 PM
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if you push the clutch in and rev it will the RPMs drop? this happened to me when my clutch was slippin on me after the engine upgrade and with the addition of the cam, the RPMS tend to drop and have a real lumpy idle sound to it like its runnin on 6 cyls and ready to die.
Old Apr 27, 2003 | 08:42 PM
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Originally posted by BIGKerneL44
if you push the clutch in and rev it will the RPMs drop? this happened to me when my clutch was slippin on me after the engine upgrade and with the addition of the cam, the RPMS tend to drop and have a real lumpy idle sound to it like its runnin on 6 cyls and ready to die.
If I do it while its not moving, it does fine... I havent tried to do it with the car moving. It better not be the clutch slipping, it doesnt feel like it did when my stock clutch was slipping, I just put a brand new McLeod Street Twin in it a couple months ago, barely has 2000 miles on it, if that much.. If I shift into a different gear the rpms will go lower than 2000, but the car bogs down and feels like its super rich. I dont know whats up with it. I also checked all the vacuum lines on the intake manifold, and everything was connected. If I managed to mix up a vacuum line would it cause that to happen? I dont think so because the car ran pretty good until last night when I started blowing the engine sensor fuse, but its worth a shot.
Old Apr 27, 2003 | 08:53 PM
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lol for your sake i hope its not that clutch cost me an arm n a leg an its not even in the car yet =/
Old Apr 27, 2003 | 10:59 PM
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it shouldn't be the clutch dude



if i can think of anything, i'll let you know

in the meantime, goodluck getting her fixed
Old Apr 28, 2003 | 12:20 PM
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TTT anyone?

I tried running it with the MAF unplugged, and runs the same with the MAF unplugged as it does with the MAF plugged in Is that a sign of a bad MAF sensor?
Old Apr 28, 2003 | 01:04 PM
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Shot in the dark here but if you reset your computor after the sensor fuse blew maybe your iac is relearning its parameters, are you getting a ses?
Old Apr 28, 2003 | 01:16 PM
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Originally posted by 97 SLP Company Car
Shot in the dark here but if you reset your computor after the sensor fuse blew maybe your iac is relearning its parameters, are you getting a ses?
My SES has been on for a while from no cats.. i would take it to get it scanned, but i dont think the car would make the trip to autozone without dying out

It just seems like its running incredibly rich, I know it is, actually, but I cant get it to get out of its "limp mode" its in...

Ill try driving it around some more and see if it goes back to normal... Weird part about it, is if I crank the car and let it sit, it idles fine. It doesnt start acting up until I try to drive it.
Old Apr 28, 2003 | 01:16 PM
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I had the problem B4. Only my car had a lot more problems than that fuse. When mine blew the car wouldnt drive over 50mph.... was EXTREMELY sluggish, and backfired also... I pulled the manifold and found lots of fuel puddled up inside I dried it up, resealed the manifold, and tried again. It would run great for a few minutes then bog down again. And sure enough, flooded with fuel. I ended it replacing the engine, cause i had a shiotload other problems. Any other ideas. The fuse could have shorted out and f***ed his MAF up. I would suggest getting a scanner and gettin any SES codes off the PCM.
Old Apr 28, 2003 | 03:31 PM
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Ok... Ive been working with it some today, let it idle for a while, it seemed to be doing fine.... but I think the reason the car is idling high after driving it and then settles down is because it is running super rich, and the PCM wont let the idle doesnt settle back down until the excess fuel is burned off. Whatever happens, doesnt happen when the car is sitting or free revved before driving. It only happens when I try to drive it. I was backing out of the driveway and the smell of fuel was almost overwhelming and I pulled back in and looked under the car at the exhaust and it was pouring out black smoke (unburned fuel). Any ideas what could have happened to cause my car to run this rich? Is this a limp mode type thing because it blew the engine sensor fuse? I replaced the fuse, any idea how to get it out of the limp mode if this is what it has went into??
Old Apr 28, 2003 | 08:29 PM
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I tried to run the car with the O2 sensors disconnected to see if that would help anything, and it did not. Car will idle fine when I first crank it and when I free rev it, but when I try to drive it (put it in gear, start driving, even does it when backing out of the driveway) it runs richer than hell... I dont know what to do. I need some suggestions.. Anyone got any ideas?
Old Apr 28, 2003 | 08:42 PM
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i would check all the plugs. It sounds to me like one of the injectors is stuck open. It happened to me before..my PCM would not send signal to one of my Injector so it was stuck open al the time..car run like **** and reaked of raw fuel.
Old Apr 28, 2003 | 09:05 PM
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a vacuum leak will cause it to idle fast

and run rich
Old Apr 28, 2003 | 09:17 PM
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Re: a vacuum leak will cause it to idle fast

Originally posted by allious
and run rich
it would have to be a hell of a vacume leak

go pull few vacume hoses of your car and tell me if u will see a dramatic differnece..i bet u wont

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