Fuel pressure not rising while acclerate

86Camarolt1
08-05-2008, 08:08 AM
My fuel pressure stays around 35 psi on acceleration which cause a stumble/hesistation. Ive replaced fuel pump, injectors, and regulator(stock) and same results.first it was doing that and the pressure would drop when you cut the car off. since I replaced the fuel pump the pressure holds when you cut the car off, but it still stays around that 35psi on acceleration.

shoebox
08-05-2008, 10:26 AM
How about the first thing you should have replaced...the filter?

Have you checked that the vacuum source for your regulator is actually getting vacuum? Does the pressure change when you remove the vacuum line at idle?

86Camarolt1
08-05-2008, 07:09 PM
Sorry I forgot to add I also changed the filter. When I unhook the vaccum for the fpr it stays at like 45-47 psi

shoebox
08-05-2008, 07:56 PM
So, it goes from idle pressure of ~35 to 45-47 when you remove the vacuum line? That's what it should do. Vacuum should also drop at WOT and therefore fuel pressure increase likewise. But you are saying it is not?

86Camarolt1
08-05-2008, 08:27 PM
correct, with the vaccum attached to the regulator at WOT the pressure goes to about 35 psi, when it should be increasing to 41+

shoebox
08-05-2008, 09:54 PM
Almost sounds like the pump is not keeping up or the lines are restricted or too small.

86Camarolt1
08-05-2008, 10:32 PM
it was working fine until this problem started but the fuel pump is a new Walbro for Lt1,as far as the lines being restricted i dunno

86Camarolt1
08-06-2008, 12:13 AM
I will check the fuel lines and fuel pump assembly tomorrow and post results

86Camarolt1
08-10-2008, 10:37 PM
well I took the entire fuel pump assembly out and examined. I did not see anything out the ordinary, I already replaced the fuel pump and filter but checked it again and all looked fine. Could burnt harness wires cause this also,this happened out the blue and there are wires bundled that did get burned but they have others that are slightly burned but were working fine before this problem occured.

86Camarolt1
08-10-2008, 10:44 PM
by the way, i am having trouble putting a scanner to the ecm, because the harness has a OBDII diagnostic connector and I heard 95' are OBDI. Im not certain if the OBD I and OBDII have the same connectors

Injuneer
08-10-2008, 11:52 PM
Shoebox can also tell you how to scan your OBD-I 95 (all 95's are OBD-I) with its oddball 16-pin ALDL connector:

http://shbox.com/1/xraycable.jpg

Check the voltage at the fuel pump, if you suspect the wires may be damaged.

Is it possible you have reversed the fuel supply and return lines?

86Camarolt1
08-12-2008, 09:31 PM
I will check it out and post results