Pete919

Does the fuel sending unit affect fuel pressure in any way or is it just for the fuel level guage on the dash?

FASTAZU

The FP and sending unit are an assembly although the pump is replaceable. The float/rheostat portion sends the fuel level to the dash gauge. Over time the small line connecting the pump to the hard line in the tank will swell and get lose or the plastic clamp come apart, resulting in pressure loss.

Pete919

Thanks. Just making sure. I know my sender is bad, I was waiting to replace it. I can't figure out my low fuel pressure issue unless my new pump is weak out of the box.

ANTI VENOM

Why did you replace it in the first place? What is your fuel pressure?

FASTAZU

What year? Did you replace the fuel filter? What FP are getting?

Pete919

94 6spd. Pressure is 38 key on engine off vacuum line on. Filter is new. Pump is new, double checked the fuel line in place of the pulsator, its tight. Put in a second new regulator. It's good. Original injectors are not leaking. Been chasing this for a while, I'm at a loss.

ANTI VENOM

What are the symptoms? 38 doesn't seem far off. Is it supposed to be approx 43?? Maybe your guage is goofy.

Pete919

Guage is fairly new too. I posted these numbers in another thread. Apparently it's running lean and the ECM is adding fuel. Strong gas smell in the exhaust
Lt fuel trim cl 16
Lt fuel trim l 149
Lt fuel trim r 139
Evap duty(%) 0
Evap solenoid off
Cyl ID 86
Rpm 750
Egr duty (%) 0
ks counter 1951
Fc1 relay off
Fc2 relay off
Iac position 11
Inj l pw(ms) 3
Inj r pw (ms) 3
Knock ret 0
Knock sensor 1951
Closed loop
Maf (gr/s) 7
Map ("hg) 9.81
Iat (f) 119
02 sensors fluctuate and are new
Tps sensor .71

FASTAZU

Not positive about the LT1 but I think at idle air off TPS should be .23v-.59v.

Cliff Harris

LT1s have a non-adjustable TPS. With the throttle closed (idle) it will read around 0.7 volts.