help...fuel pressure Q?

[czocco]

1996 v6 vortek

cant start unless I put gas in throttle opening....then runs a little rough..

Do I check pressure at port with engine running? or in start position?

and


whats the spec on the pressure for this model?

I can get a little dribble when in start position...and a good stream when running.

fuel filter replaced ..throwing no codes...any ideas?
CZ

[scholzee]

To check the fuel pump you will need a fuel pressure gauge like this:

Sunpro Fuel Pressure Tester

Sears item #00902169000 Mfr. model #CP7818

Large easy-to-read 0 to 100 PSI scale tests fuel pump check valve, fuel rail pop-off pressure, fuel rail deterioration and leaking injectors. Learn more

I believe it is $39.95 at Sears and you can get them at other automotive places, I just use Sears as a reference because everyone usually has one near them. The gauge screws onto a valve on the fuel rail near the top back part of the motor at the base on the windshield. I forget the exact specs but believe it is at least 55 to 65 psi and they really need good fuel pressure to run the injectors. I just replaced the fuel pump in mine it is about $350 from the dealer, I bought an aftermarket one for $220 I forget the name but can look it up if you need it. Mine had about 52 psi and would run but was hard starting because the check valve would let the fuel pressure drop to 0 as soon as the truck shut off, so it hard to crank for awhile to build up the fuel pressure and prime the fuel rail. If the fuel pressure is good you will need to check for spark, if no spark you may have a bad module. Mine is a 96 with 155K miles they are not too problematic of a vehicle Good luck!!

[czocco]

Originally Posted by scholzee

To check the fuel pump you will need a fuel pressure gauge like this:

Sunpro Fuel Pressure Tester

Sears item #00902169000 Mfr. model #CP7818

Large easy-to-read 0 to 100 PSI scale tests fuel pump check valve, fuel rail pop-off pressure, fuel rail deterioration and leaking injectors. Learn more

I believe it is $39.95 at Sears and you can get them at other automotive places, I just use Sears as a reference because everyone usually has one near them. The gauge screws onto a valve on the fuel rail near the top back part of the motor at the base on the windshield. I forget the exact specs but believe it is at least 55 to 65 psi and they really need good fuel pressure to run the injectors. I just replaced the fuel pump in mine it is about $350 from the dealer, I bought an aftermarket one for $220 I forget the name but can look it up if you need it. Mine had about 52 psi and would run but was hard starting because the check valve would let the fuel pressure drop to 0 as soon as the truck shut off, so it hard to crank for awhile to build up the fuel pressure and prime the fuel rail. If the fuel pressure is good you will need to check for spark, if no spark you may have a bad module. Mine is a 96 with 155K miles they are not too problematic of a vehicle Good luck!!

Ok thanks...but what about the position of the ignition when testing for pressure....ON..or..Running?
CZ

[Mikado14]

Both.... There is a start pressure and a run pressure. Start pressure is higher than run.