1999 GMC C2500 fuel pump

VIEQUES

MEMBER
1999 GMC C2500
164,000 MILES

My truck has no power when accelerating. I have replaced the spider fuel injectors, new O2 sensors, New cat converters, new fuel filter, new distributor cables and spark plugs, cold air intake. When I tested the fuel pressure with the engine off key on the pressure is 50psi, with the engine on the pressure drops to 45psi. I wanted to know if I need to replace my fuel pump?

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

Hi:
I need to know what size engine you have so I can look up the fuel pressure specs.

Was this

answer

helpful?

Yes

No

Tuesday, August 20th, 2013 AT 6:05 PM

VIEQUES

MEMBER
3 POSTS

5.7 350 vortec

SPONSORED LINKS

Was this

answer

helpful?

Yes

No

Wednesday, August 21st, 2013 AT 3:07 AM

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

My info on a 1999 5.7L shows 60 to 66 psi.

check for a restricted fuel line or filter. The easiest way to do this is to get an adapter and check the pressure before the filter.

Take a look at this page. It explains how and what to check for one step at a time. Let me know if it helps.

http://www.sunlitcomet.com/pdf/automotive/tahoe/98-99/1999-Tahoe-Fuel-Sytem-Diagnosis.pdf

It says for a tahoe, but it is the same engine and year.

Was this

answer

helpful?

Yes

No

Wednesday, August 21st, 2013 AT 6:36 PM

VIEQUES

MEMBER
3 POSTS

Like I stated on my first message I have already put a new fuel filter. This was the last thing I did thinking that it was the filter that was restricted. I have already replaced every component of the fuel system and still not making any difference.

Was this

answer

helpful?

Yes

No

Thursday, August 22nd, 2013 AT 2:48 AM

JACOBANDNICKOLAS