1990 200 missing/lean under boost

[David Yentema]

Yea, I was wondering if it was a fuel pump. According to the gauges my
pressures are fine(don't have them in front of me, but they were within
spec) I've been tempted to hook my gauge up and position it in front of the
windshield so I can watch and see if it drops off under boost.

What's interesting is it only does it under boost, I brought the car to
redline without boost and it did fine
On Jun 8, 2011 6:10 PM, "Robert Myers" <bob at chips-ur-s.com> wrote:
> *This message was transferred with a trial version of CommuniGate(r) Pro*
>
> I had one that acted like that which eventually was traced to a
> failing fuel pump and resultant low fuel pressure. Also, that was
> with an almost brand new pump. Replaced one failing pump with a
> brand new failing pump.
>
> Good luck,
>
> Bob
>
>
>
> At 05:54 PM 6/8/2011, you wrote:
>>*This message was transferred with a trial version of CommuniGate(r) Pro*
>>This is an issue i've been dealing with for a while, Car is a 90 200
>>Quattro, MC-2, Ben Swann 2+T super chip (mac-14)
>>
>>basically what it's doing, it idles fine, starts up fine most of the
>>time (accumulator was leaking, so I pulled it, made no real
>>difference with starts, still vapour locks, but that's besides the
>>point) and it will pull to about 6psi, but the second it goes over
>>that, my NB shows full lean, and if I push a little further you can
>>feel it miss slightly. I know a miss will show lean, and that
>>actually running lean will show lean.
>>
>>I have tested and verified:
>>ISV, IAT, Idle/WOT switch, ignition coil, cap, rotor, wires ohm out
>>fine but they're old so I plan on replacing them anyway, pressure
>>tested the intake manifold and fixed the few small leaks I found.
>>
>>
>>I also bought an adjustable spark gap tester, adjusted it to the
>>absolute max distance the coil would jump, and tested each of the
>>wires, all of which were able to jump the gap no problem
>>
>>
>>I'm running out of ideas here, and there are no codes being set. The
>>only other idea I have is to tape off the intake snorkle and run
>>pressure into the whole intake and see if anything is leaking
>>(thinking being a vac leak before the turbo, but after the metering
>>plate would cause a lean condition, especially as the turbo spools
>>and sucks in more air..
>>
>>any suggestions you guys can give would be awesome
>>
>>Thanks,
>>Dave
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>>
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