OK i am truely puzzled i have no clue what this could be...

Details on car
87 T2 w/
moderate street ported s4 t2 motor
Rtek 1.7 + 720cc injectors
walbro 255 fuel pump
3" ehxuast and 3" intake.
ported waste gate on stock turbo.
emissions removed. ( and no 02 sensor wide band currently in place for testing)
NGK AFX wide band
Autometer boost gauge.


OK so if i barly give it gas around town it runs fine air fuels seem to go fairly rich at real light throttle 12's and then around 14-15 around light throttle ( which is fine with no o2 sensor)

BUT if i try and get on it ( 1/4th throttle or more) at say 2500 rpm or more it either stays lean and starts bogging/missing as i aproach boost( like -5 vacume or so) and af will peg out my wide band at 16:1

or a/f start droping down like they should for a second or two enuf to make it start spooling good and i get into a few pounds and then the a/f start leaning right back out toward 15:1, and then it starts missing/bucking/detonating/god knows what again.

now i know a miss will show a full lean but the a/f is quite lean before it starts missing it seems like the a/f just dont seem drop down like they should when getting on it.

ive replaced/swaped or have tested
fuel filter
had injectors flow tested
rtek 1.7 ecu
air flow meter
boost sensor( stock gauge works fine, ive done a test with no boost sensor same result)
air intake sensor
water temp sensor
TPS
leading coil pack
fuel pump + checked voltage and wired pump for high voltage at all times.
new spark plugs bur9eq all around.
checked timing

now ive tried getting on it for a few seconds at higher rpm like 4K and it gets quite lean as well and can bog hesitate ect at a/f around 14's going into boost (SCARY!!)

im worried im going to blow the motor so i need to figure out what this problem is

Could the street port cause such lean conditions i would think the AFM would see the increase of airflow and compensate??

im puzzled any input would help.

 

I think you pissed off the rotary gods ... Have you tried washing your car? haha

wow you're thing is crazy has to be wiring or some weird vac line issue.

 

1. Do you have the Rtek 1.7 with the stumble elimination fix? This was only released recently. You can send it in and they will do it for cheap, see their website.

2. all your grounds clean?

3. what is your fuel pump voltage under WOT? Did you properly rewire the fuel pump?

 

Same thing's happening with my T-N/A.
It's sooooooo amazingly frustrating!

 

ive been having a similar problem for the longest time now. Except it always richens up as soon as im above 1-2 psi of boost. But sometimes getting there in low vacuum, it will lean out to 16-18's

try and see what happens if you stay in it, up to about 4-5 psi, but only do it in 1st gear/low load.. this should prevent too much harm if it detonates

i saw another thread on a similar problem, and they suggested it was leaky injector grommets causing vacuum leaks.. and my problems started right after upgrading the secondary injectors.. coincidence??

 

I put 10 bucks on it being your resistor relay not clicking over, and your pump is only getting 9v under load.

 

Any links right off on how to test the fuel pump resistor pack?