What exactly happends when you overboost on a stock chip? my car seems to run fine right now when i only go partial throttle and hit 5-7psi. I peak at 10psi and it runs rough. is this a result of overboosting on a stock chip. it continues to run like ass for a while as well. But then again it is kind of intermintant so it could be the flex leaking as well.
Just wanted some clarification.
Shane
Can't belive you run 10# and not get fuel cut. Thats what happens when you over boost. Unless you have taken the steps to prevent fc. To run that kind of boost your ignition has to be in tip top shape. At 10# you could even be getting detonation. :( :( One step colder champion copper plugs fixed my misfires or detonation, don't know which it was.
Obviously you can see your boost gauge. :lol: Looks Good.
jud
Well i do have ALL brand new plugs and wire. Stock Delco's. I also run nothing but 93 Octain. PLUS i am at 5000+Ft Altitude (Colorado) which makes a HUGE difference (MUCH THINNER AIR).
if you over boost does the computer get pissed and run like ass for a while or just when the boost goes up?
Shane
Overboost is instant, like shutting the motor off. If you keep your foot in it it will come back on in 2 or 3 seconds and run normally for a few seconds and cut off again. The sos light will come on for a few seconds. The light comes on due to the lean condition from fuel cut. Doesn?t sound like you have fuel cut although you should have. Must be due to the altitude. Has it ever backfired through the intake? Is it missing or just no power? Running like an ass is kinda hard to diagnose.
Ive got another question about your pipe.Where did you get your flange. I can find one for everything but 2 1/2 2 hole.
jud
Quote from: sleeperred90tgpOverboost is instant, like shutting the motor off. If you keep your foot in it it will come back on in 2 or 3 seconds and run normally for a few seconds and cut off again. The sos light will come on for a few seconds. The light comes on due to the lean condition from fuel cut. Doesn?t sound like you have fuel cut although you should have. Must be due to the altitude. Has it ever backfired through the intake? Is it missing or just no power? Running like an ass is kinda hard to diagnose.
Ive got another question about your pipe.Where did you get your flange. I can find one for everything but 2 1/2 2 hole.
jud
The light comes on specifically because of the fuel cut. When the ECM triggers the fuel cut it Illuminates the SES light for 10 seconds, not becaues of a lean condition.
He probably isn't hitting the fuel cut at 5000psi and 10lbs of boost on a REAL boost guage because the fuel cut is at 9.5 psi absolute pressure above atomospheric at sea level. I don't know the calcs off hand, but he's probably seeing 7 psi of real boost.
Look for loose connections and lines would be my suggestion. If it runs bad after hitting 10lbs, then there obviously is something else wrong. Maybe something is blowing off, or the fuel pressure regulator is having issues at higher boost. Fuel filter/fuel pump?
Chris
Chris, of the 100 or more times I have hit fuel cut the sos light never comes on until I have released the pedal and am cursing down the road.
Why? If the computer sent a signal at fc I would think it would be an instant light. that?s why I assumed it was the oxygen sensor relaying the lean condition which it is when the fuel shuts off. Any theories?
PSI is psi his gauge doesn't feel the difference at 5000' or at any depth it's a closed system. He could be in space and the gauge would read the same as long as he had something to pump into it.
Sounds like it is chipped (I think he is checking that now) unless he is getting a faulty pressure/vacuum reading but I think he installed the line at the back of the manifold so that?s about the best reading you can get. As for his surging gauge (another post) I get the same thing. Its not steady it fluctuates about 1 psi back and forth I just kinda have to pick the middle. Maybe it would smooth out if I had 8 cylinders. :lol: :lol:
Jud
I can Over boost {13-14 psi} on my Stock Chip but it too Runs Like ass untill It gets down to 9psi then Runs Fine......
Right now I have a Problem where when I just barily hit my gas my RPMs Drop about 200rpms and my car starts to shudder?? would this be a bad TBS??or something?? happens when Cruise is on and when I just want to accell slowly but WOT works Just Fine most of the time but one out of ten times I do hear a Pop but then works fine...what would cause this??
Quote from: sleeperred90tgpHas it ever backfired through the intake? Is it missing or just no power? Running like an ass is kinda hard to diagnose.
Ive got another question about your pipe.Where did you get your flange. I can find one for everything but 2 1/2 2 hole.
jud
Yes it has backfired through the intake. It runs normal spreatically. but most of the time. Surges and shutters. shutters even out of boost at low rpm (partial throttle) cursing down the road.
Shane
Quote from: Chris AQuote from: sleeperred90tgpOverboost is instant, like shutting the motor off. If you keep your foot in it it will come back on in 2 or 3 seconds and run normally for a few seconds and cut off again. The sos light will come on for a few seconds. The light comes on due to the lean condition from fuel cut. Doesn’t sound like you have fuel cut although you should have. Must be due to the altitude. Has it ever backfired through the intake? Is it missing or just no power? Running like an ass is kinda hard to diagnose.
Ive got another question about your pipe.Where did you get your flange. I can find one for everything but 2 1/2 2 hole.
jud
The light comes on specifically because of the fuel cut. When the ECM triggers the fuel cut it Illuminates the SES light for 10 seconds, not becaues of a lean condition.
Never once seen a SES light... but then again you guys know how the dashes on these cars are.. Who knows whats working properly untill the cluster is resolderd.
Shane
Quote from: Chris AHe probably isn't hitting the fuel cut at 5000psi and 10lbs of boost on a REAL boost guage because the fuel cut is at 9.5 psi absolute pressure above atomospheric at sea level. I don't know the calcs off hand, but he's probably seeing 7 psi of real boost.
Look for loose connections and lines would be my suggestion. If it runs bad after hitting 10lbs, then there obviously is something else wrong. Maybe something is blowing off, or the fuel pressure regulator is having issues at higher boost. Fuel filter/fuel pump?
Chris
I just put in a new fuel filter, pump and strainer. I am going to take it to my buddies shop and have them take a look.
I also notice a tinny rattly/gargly noise when i am at WOT....
Shane
Not much time to talk but you sound in need. And a lot of this will just fall into place once I say it so sorry you just about already know this :oops: . With the cracked crossover pipe leaking and doing its rich thing to the fuel mix, this along with the over-rich fuel tables in the stock chip specially at 9psi and up will give you a rich bog, add to that with your breathing such thin air and it all adds up, just have someone check your butt for black smoke when it does that, or you may notice it out your rear window, or just note how much blacker than normal (some is normal) your exhaust tips are, told you it would be about what you were going to think next 8) .
Jeff M
Quote from: Jeff MNot much time to talk but you sound in need. And a lot of this will just fall into place once I say it so sorry you just about already know this :oops: . With the cracked crossover pipe leaking and doing its rich thing to the fuel mix, this along with the over-rich fuel tables in the stock chip specially at 9psi and up will give you a rich bog, add to that with your breathing such thin air and it all adds up, just have someone check your butt for black smoke when it does that, or you may notice it out your rear window, or just note how much blacker than normal (some is normal) your exhaust tips are, told you it would be about what you were going to think next 8) .
Jeff M
It does do what you describe. I am in the process of ordering the parts for X-over pipe. I just wanted reasurance that fixing the pipe was most likely the solution before i go and dump more $$ into it to end up w/ the same problem.
Thanks Jeff,
Shane