I Think I Have A Fuel Problem.

[~R33AzzA~]

Hey guys,

For the past month my car has been driving different when on boost. If the car makes more than 6 lbs it actually feels it is loosing power.. I had a mate drive my car who has alot of expirience with big hp turbo cars, and he thought that the turbo might be rooted as there was evedent squeeling.

So tonight we put a new rebuilt ballbearing turbo in running only 7 lbs and the car feels shit, almost like as it comes on boost it hits a wall and stays there as the revs rise.

My mate said that it sounds like it is detanating on boost. He followed me up the road and said that it smealt pretty lean (smells like its burning ur nose, his words). What are your thoughts on this. Also i have an apexi pen turbo timer in the car which is wired into the o2 sensor, it is getting a reading of 15.5-13.5 on iddle and at full boost it droppes to 12.3 - 12.0, then once off the throttle it will head to 19.0-20.0. Are the turbo timers usually acurate with the o2 a/f?

Is there a fuel problem?? Maybe fuel reg? Computer? A/F meter?

Current mods are: turbo back exhaust, front mount, bosch 023 fuel pump, fully manulised auto.

I am going to book some time on the R&E dyno hopfully next week.

But any help at all is realy appreciated.

Edit: I just found this, I think this is the same thing mine is doing. http://www.skylinesaustralia.com/forums/R3...hl=running+lean

AzzA

[NYTSKY]

Take it to your tuner.10 mins on the dyno will give them an idea what the problem is.

[~R33AzzA~]

Take it to your tuner.10 mins on the dyno will give them an idea what the problem is.

I will get it on the dyno as soon as i can. But for now i have to drive it and don't want to kill it.

Doesn't anyone have any ideas?

[GTR-32U]

hows the ignition advance ? Anything that may have affected ignition timing ? As it sounds like timing is retarded

[R31Nismoid]

Your mate said the turbo was dead so you just changed it?

Was it even dead to begin with?

Anyhow, stop listing to your mate dude. Get it onto a dyno and get the sniffer up the exhaust and find out exactly whats going on

You really cant tell otherwise just on what you think it might be doing... i wouldnt be trusting the AFR jibwa on the pen timer as far as i could throw it.

If you can, just dont drive the car. Or stay off boost and you should be fine.

[~R33AzzA~]

GTR-32U- Yeah I was thinking maybe the timming. It was very advanced when i bought the car 10 months ago, I saw dr drift about a seprate issue a few months ago when he noticed the advancment and retarded it. So its pretty likely.

R31Nismoid- Once the turbo came off it was visably rooted as the impeller was touching on the housing when it was turned.

I agree with staying out of boost I might keep the wast gate open to make sure it doesn't boost. (The roads round my area are pretty hilly, better to be safe.)

Thanks for your inpute guys.

[race_snooze]

the making noise from the turbo, is more then likely lose exhaust manifold, or cracked.

[~R33AzzA~]

the making noise from the turbo, is more then likely lose exhaust manifold, or cracked.

I did factor this but it was checked and elimanated. I put the new turbo on and the noise is gone.

That problem is fixed.

Onto the existing issue.

An engineer at work thinks that it sounds like I might have valve overlap happening. This would explain why there is boost but no power, the air from the turbo is coming into the chamber and escaping out the exhaust at the same time.. Also i have noticed that there is alot of boost evident even at say 2000 rpm also supporting the overlap theory.

Thoughts on this?

[~R33AzzA~]

Update

I returned my timming to the standard position and the car went a little better. I then decided to change the AFM with my mates one.

Once the new AFM was in, the car was perfect.

The timming still has to be done properly though, so ill book the dyno time, to make sure its all sweet.

Thanks for your ideas.

AzzA