99 Suburban fuel pressure problems

NEWT8243

MEMBER
1999 GMC SUBURBAN
V8
4WD
AUTOMATIC

I installed a new carter fuel pump in my 99 suburban. Two days later I cant get any fuel pressure built. I unhooked the return and turned the key on/off no fuel came out of the line which leads me to think the pressure relief valve is good. When I installed the new pump it came with a wiring conversion kit. The tails on the new wiring harness were pretty long so I cut them a bit, but I left more slack so I could hook the harness up easier than unhooking it was. Could the extra wire screw with the pump, or was I lucky enough to have just gotten a B.S. Pump? P.S.I is only at 51 +/- 2 lbs.

7 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Your fuel pressure is low

4.3L, 5.0L & 5.7L 60-66psi (4.2-4.6)
4.8L, 5.3L, 6.0L & 7.4L 55-62psi (4.0-4

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Monday, December 6th, 2010 AT 12:26 AM

NEWT8243

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4 POSTS

O.K. But, why

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Monday, December 6th, 2010 AT 12:44 AM

HMAC300

MECHANIC
48,601 POSTS

You should change the fuel filter if haven't already. Also the harness should be replaced the full length of what was supplied. Make sure to solder the connections and use shrink wrap around them. Don't just crimp them on.

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Monday, December 6th, 2010 AT 1:00 AM

NEWT8243

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4 POSTS

Could the filter (new) cause low pressure?

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Monday, December 6th, 2010 AT 1:16 AM

HMAC300

MECHANIC
48,601 POSTS

If it were on backwards a fuel filter could cause that. The pump maynot have gotten on the clip real well also. The wires going to the pump are very fine and they can break if it wasn't put in right.