K-Tune

iTrader: (26)

what we are dealing with

S4 '88 JSPEC T2
Walbro 255lph(new)
new fuel filter as well.
1 trailing coil doesn't fire

watching the narrowband...the engine seems nice and rich and happy when revving at partial throttle.

when throttle is fully depressed everything seems fine until boost starts to come in, immediate breakup and the narrowband pegging out lean.

i realize there are a lot of things that could cause this, but wanted opinions.

dirty injectors
timing(ignition)
wrong vacuum source for regulator
TPS out of adjustment

K-Tune

iTrader: (26)

bump, still cant figure this out.

maybe the secondary injectors arent going?

SureShot

I'd first check the Ohms sweep on the TPS.
Then check the fuel pump voltage.
Then check the fuel pressure.
Maybe a loose secondary injector plug?

K-Tune

iTrader: (26)

its literally as soon as the engine sees 1psi of boost.

under light throttle it revs very nicely. i'll go check a few things..

SureShot

Could be as simple as worn out plugs or plug wires..

K-Tune

iTrader: (26)

plugs and wires are new.

K-Tune

iTrader: (26)

http://www.youtube.com/watch?v=ryCu_5breWw

thats with the engine cold.


listen around 5krpm
http://www.youtube.com/watch?v=vxhto...elated&search=

The Wankler

iTrader: (14)

I had smiliar problems till I changed out my injector clips for new ones.

K-Tune

iTrader: (26)

well..i was just out there messing with things.

when i manipulate the throttle by hand, the moment the TPS leaves contact and is fully extended my primary injectors click, when it comes back into contact they click again.

so right on that edge only my primary injectors click, shouldn't it be the secondaries engaging at that point?

The Wankler

iTrader: (14)

The secondaries come on around 3650 rpm or so. I do not ""believe"" you need to be under load, but do not recall. Do a search on it. Hailers explained it pretty good in another thread some time go.