TurboBandit

Firstly, this is not a vaccum leak... i promise you.


Hears the deal... if i'm less than 2500 rpm, the engine (LS1) will act normally. Rev, and come back down to idle.
If i rev it to 3k rpm or higher, it will HANG there for a good 5 seconds, before slowly coming back down.

This makes driving VERY scary, as i get off the gas, and the car keeps driving!!!

It's not a vaccum leak. I have a vaccum gauge, and it reads 17 lbs at idle... and that's with a 112 LSA cam. I watch the gauge, and remove a vaccum line, and it goes down to about 5lbs of vacuum... so i know it's not a leak. Also, i checked the intake manifold gaskets, cleaned them, and re-installed. All vaccum lines are new.

This happened over-night. I changed a spring in my blow off valve, and drove to the store forgetting to put the vaccum line on... engine acted funny, so i popped the hood, saw the line unplugged, so i plugged it back in... From then on out, it has acted the same way.

It's not the MAF, i swapped it with a friends working one, and still the same problem.

I've reset the cpu by unplugging the battery, turning on the headllights and all that jazz to drain the system. Still same issues...

THink its the tune?! Any suggestions?

99LsOne

iTrader: (2)

Sounds crazy, I can't think of anything. Something with the trans maybe. Heck idk I was goin for the vaccum but sounds like you've ruled that out.

Frost

iTrader: (45)

Check your BOV isn't leaky after you put it back together... I mean you said that's what started it and taking apart a BOV doesn't have any impact on PCM tuning.

AutomagicLS1

iTrader: (18)

Try replacing your IAC. If it was the tune it might be the throttle cracker/airflow tables but if it just started its somthin else I bet

TurboBandit

Hmm~
I'm positive the BOV isnt leaking... it has a big fat o-ring. It's the Type S kind.
And as of now, it's the stock tune, stock injectors, stock everything just to get it running. Hasn't been on the dyno or anything yet.


Well, there's one more piece of the puzzle that i should share. When i was doing the spring in the blow off valve, i noticed a mist of oil inside the pipes, and on the MAF. I blew out some of the oil with my air tools' air gun. I was thinking i may have damaged one of the tiny resistors, but we plugged in a friends, and it still did it.


Anyone ever drive around with a vacum line off... have the computer "fix its self" and re-learn its'self, plug the vacum line back in and this still happen?


I mean, i can see the boost/vacum gauge, and it's still on 17lbs of vacuum... can not possibly be a vacum problem

MY99TAWS6

iTrader: (3)

Are you using hptuners..if so you can send me or post your tune.
You should mabye go to 2bar sd tuning anyway and ditch the maf. Pretty simple if you have hptuners. Just buy a 2 bar sensor and switch over. No more mafs to worry about.

TurboBandit

It's stock tune, stock injectors, stock everything.

No boosting... The whole setup is on there, ready for boost, but i mean just barely touching the gas, up to 3k rpm, and it hangs for a loooooong 5 seconds, then comes back down to idle.

I'm not using HP tuners, or anything right now, all stock just to get all the bugs worked out.

So besides vaccum leak, no one has ANY idea?!?!?!?!?!?!?!?!? ////////////////////

Frost

iTrader: (45)

If you engine and tune are stock and your TB is fully closed, you have unmetered air coming in. AKA a leak..

TurboBandit

There is NO LEAK boys....

New update, getting closer to the solution....


i UNPLUGGED the Throttle Position Sensor, and the rev hanging went AWAY!

hmm... there a way to reset the TPS?


So boys, like i said, there is no leak, so anyone ever heard of something like this?

junkindatrunkmx6

iTrader: (1)

Have you replaced your tps yet? I'm having similar problems.. Just curious if that fixed it for sure.