Intermitten Vacuum leak? Wtf?
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From: Florida
Car: 1992 Camaro RS
Engine: Yet another 350 TPI
Transmission: Borg Warner 6 spd
Axle/Gears: 3.73
Intermitten Vacuum leak? Wtf?
This is Kingtal0n, im using 92Blue's name.
I just got the TPI running on my new 355.
Im having 92blue drive me around, while i tune it with my laptop (commander 950)
The problem occurs randomelly, for a random amount of time.
Suddenly out of no-where, the idle will jump from 750~rpms (where its supposed to be) to about 2500 RPMS. it will sit there for a random amount of time, and eventually work its way back down to proper idle speed. if the car is in gear when this happens it will accelerate slighty, or hold its speed, as if i was touching the gas...
Ive disabled the IAC and checked the TPS for sticking throttle, those are ruled out. Ive double checked all my vacuum lines, I only have 3, (MAP, brake, AFPR)... none are leaking (testes with propane and carb cleaner)... there is no EGR (blocked off) and the injectors PW isnt changing when this occurs. the timing is stable as well, verified with timing light.
random, probably a vacuum leak somwhere, but intermitten? today it hasnt done it even once, but yesterday it did it like 5 times. I even datalogged it, very very strange.
I just got the TPI running on my new 355.
Im having 92blue drive me around, while i tune it with my laptop (commander 950)
The problem occurs randomelly, for a random amount of time.
Suddenly out of no-where, the idle will jump from 750~rpms (where its supposed to be) to about 2500 RPMS. it will sit there for a random amount of time, and eventually work its way back down to proper idle speed. if the car is in gear when this happens it will accelerate slighty, or hold its speed, as if i was touching the gas...
Ive disabled the IAC and checked the TPS for sticking throttle, those are ruled out. Ive double checked all my vacuum lines, I only have 3, (MAP, brake, AFPR)... none are leaking (testes with propane and carb cleaner)... there is no EGR (blocked off) and the injectors PW isnt changing when this occurs. the timing is stable as well, verified with timing light.
random, probably a vacuum leak somwhere, but intermitten? today it hasnt done it even once, but yesterday it did it like 5 times. I even datalogged it, very very strange.
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Oh, yeah - right...
It's probably really Mark A. Shields using KingtalOn's name using 92blue's logon, just to keep from running up the post count...
Have you eliminated the brake booster? They can leak unexpectedly and intermitently. I was going to suggest the EGR, but I see you've already eliminated that.
It's probably really Mark A. Shields using KingtalOn's name using 92blue's logon, just to keep from running up the post count...
Have you eliminated the brake booster? They can leak unexpectedly and intermitently. I was going to suggest the EGR, but I see you've already eliminated that.
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Joined: Mar 2001
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From: Fl
Car: 5.3L turbo 2800lbs RWD
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Axle/Gears: 3.512
lol vader
tonight it started again, but differently.
i put it in neutral and the vacuum leak would come and go slowly, evenly, it would idle up to 1500 rpms, then back down to 1000, then back up, like a hunting idle almost, i pulled off the brake booster, AFPR, and air cleaner ducting, IAC motor, TPS wire, and it was still doing it.
what are the chances of an intermitten gasket leak in the intake or plenum or runners? im going to try to find it with propane again.
or maybe its somthing else leaking somwhere?
let me ask this, on the plenum there are 3 vacuum holes in the back, and 3 in the front on the TB.
On the INTAKE manifold, it appears there is only ONE vacuum hole, next to a runner on the driver side. THATS Where i have the brake booster plugged in because the one by the plenum is blocked by my regulator. could that be causing this problem?
tonight it started again, but differently.
i put it in neutral and the vacuum leak would come and go slowly, evenly, it would idle up to 1500 rpms, then back down to 1000, then back up, like a hunting idle almost, i pulled off the brake booster, AFPR, and air cleaner ducting, IAC motor, TPS wire, and it was still doing it.
what are the chances of an intermitten gasket leak in the intake or plenum or runners? im going to try to find it with propane again.
or maybe its somthing else leaking somwhere?
let me ask this, on the plenum there are 3 vacuum holes in the back, and 3 in the front on the TB.
On the INTAKE manifold, it appears there is only ONE vacuum hole, next to a runner on the driver side. THATS Where i have the brake booster plugged in because the one by the plenum is blocked by my regulator. could that be causing this problem?
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