Help! Running very rich.

[Ironlung]

This is the fast GN that I sold to my dad. It's had this re-ocurring problem as long as I've owned it, but it's gotten so bad now, it's unbearable ! Fuel pressure is set around 40lb vac off. When you start the car, occasionally it will jump to 60lb-80lb at idle, and of course raise plum off the guage when reved up. It runs extremelly rich and will not idle when cold. Blows black smoke and I'm sure it has fouled the plugs again. When it dies on start up, it floods out and is extremely hard to re-start. It has always ran a little rich, and this rich on start up has come and gone. My mom tried to drive the car to a show this weekend and it died several times and she could not get it re-started in the middle of an intersection. So I need to get this fixed for good.

Combo:

009 injectors
49 turbo
Houstin down pipe
ATR exhaust
LT-1 Mass Air with translator (leaned out)
Alky Injection
and all the regular mods

Things I've changed hoping to help:

Warlbo 340 fuel pump
Billit fuel pressure regulator (does the same with stock)
Idle air control motor
Swapped chips (helps for a little while, but comes back)
Oxygen sensor
Checked for vacuum leaks
No codes thrown

Where do I go from here???

 

[ES1]

Pinched fuel hose? Look at tank.

 

[scottyb]

Originally posted by ES1
Pinched fuel hose? Look at tank.

ditto that, clogged or pinched return line.

 

[Ironlung]

Thanks! Tank will hit the ground this weekend .

 

[scottyb]

Something just hit me. If there is a pinch or clog, I'd think pressure would go down when you rev it because the engine uses more of the fuel.......thr FPR should raise the pressure when vac goes down, but a pinch or clog would render the FPR useless since your pressure goes beyond the normal operating range of the FPR.

I'd double check the FPR, its seal and installation. Maybe grab a 237 off a 3800 at the yard just for testing... then drop the tank if still no work.