What happens after 1.5bar?

Mihnea Cotet mik at info.fundp.ac.be
Thu May 1 21:54:29 EDT 2003

Mike, Dave,

I too think Dave is experiencing the overboost fuel pump cut-off but I'd
rather bet on a small boost leak that triggers the cut-off.. The reason I'm
saying this is because the overboost fuel pump cut-off is determined by air
flow across the MAF, not actual boost, so no matter the boost level he's
running, if the MAF signal is over the programmed max level, the fuel pump
cuts off, I've BTDT and tested that in real time with an eprom emulator
recently, just for the fun of it.

So I'd suggest you Dave to check for leaks in the intake system, possible
culprits are the IC to intake pipe hose and possibly the bypass valve too...



At 11:39 1/05/2003 -0700, Mike Miller wrote:

>----- Original Message -----
>From: "Dave" <morpheus0213 at yahoo.com>
> > Fellow Listers,
> >
> > After the turbo produces 1.5bar pressure what happens?
> >  I'm trying to pinpoint my violent bucking problem, it
> > seems as though when I get to 1.5bar the car will
> > violently buck.  I'm guessing it's electrical because
> > it seems to continue happening even when it doesn't
> > reach 1.5 after the initial instance.  I am leading
> > towards the ECU for that reason guessing that it must
> > be reset to continue normally until 1.5 is reached
> > again.  Of course I hope it isnt I'd rather not but
> > another grand into the car right now but any input is
> > appreciated.
> >
> > Thanks in advance,
> > Dave Pianka
>This sounds like you are hitting the overboost fuel pump cutoff.  Once that
>is triggered, you cannot get above 1.3 bar until the ignition is cycled.
>Perhaps your boost gauge is off and you are seein gmore than 1.5bar to cause
>mike miller
>helmville mt
>200q20v mailing list
>200q20v at audifans.com

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