First off this is my first real tbread, glad to be here.
Quick rundown on the car
87 t2 mild streetport motor (90 psi across the board)
3" straight exhaust, corksport piping, rc750 secondaries. Stock 550 primaries. Walbro 255.
Pretty much everything else is stock (stock turbo and top mount)
The car has a slight stumble around 2k to 3k rpm at free rev
Also has absolutely no power until boost kicks in.
Things I've done or tried:
Corrected idle and timing
Leak tested the intake for any leaks
Swapped out maf and tps
Checked all the wires and grounds that I know about.
Tried stock ecu, rtek 1.7 and 2.1
Throwing no codes at all.
Is there ANYTHING I'm missing? I'll respond if I've tried what anyone offers. Please help me I'm at whits end. I'm in GA and the car is at my buddies house (scorp7)

 

no fuel pressure regulator?

 

The stock one, yes. Was thinking of adding an aftermarket one

 

a wideband would probably tell you the problem.

 

tps i assume is adjusted properly.


pressure sensor hooked up? has the setting there been screwed with?


have you tested your coils?

 

Tps is adjusted correctly.
I've hooked a wideband up and idled around 12.5 dropped to around 11.5-11.9 under boost (this was during a free rev)
Boost sensor is hooked up correctly
Coils were tested as well

 

is the smog pump still on and working?

 

No smog pump and a more acccurate description of the stumble would be at around 1/3 throttle or around 0 psi imo.

And when "stumble" is stated, it bogs when you push the throttle to free rev and then typically backfires at about 1/3 throttle or 0 psi. Although it doesn't always backfire, it always stumbles.
The next things that I plan on trying is to monitor running fuel pressure and datalogging while driving around the block.

 

sounds like a TPS issue, 1/3 throttle is right about the point where the narrow range TPS goes wide open. try disconnecting the TPS and do another test, don't beat on it but drive where the issue normally occurs.

 

I agree. I have set the tpms multiple times and confirmed with the rtek 2.0. I also have tried 2 different throttle position sensors. I will try to disconnect it and see what results I get.

Also, rotaryevolution, do you mind if I ask your name? I believe I may have met you once before when I lived in Greenwich and went to a Bear mtn 7 meet.

 

my name is Ben but i rarely make it out of california and nevada, so it's unlikely since i've never been to Greenwich.

maybe one of my clones escaped, i try to keep track of them..

 

I think I spied one..lol!
it was a cross between Justin Bieber and the Incredible Hulk..Just Incredible we called him!

 

You would have ruled the Catskills circa 1950.

 

Lmao, guess it was a different guy that claimed a similar name hahaha...

 

i would prefer to roam free in the scottish highlands.

 

I assume that "roaming free in the highlands" is a euphemism for freeballing in a kilt.

 

actually it would be trolling in a panzer tank keeping people off my "lawn".