Can someone please answer this??

Emfinger · 06-12-2009, 04:32 AM

I have a 1998 Z71 5.7 liter my fuel pump staopped running i checked the fuses and relay, then i pulled the bed and changed the fuel pump with on i ordered offline(pump only). The new pump wasn't the same but i put it in, then i found i had no power to my fuel pump so i ran a wire to it. Now it runs(FP)
but it will not start, you can put gas in the TB and it will start you can drive it but not accelerate hard, you can easy into it and go good but if u punch it, it sputters. I changed the fuel filter, and still have the same results. My question is why and what is the difference between all the models and the 1998 fuel pump $115 for a 1995 to 1997, and $310 for a 1998? And why dont i have power to my harness on top of fuel pump? Please help me.

gmctrucks · 06-12-2009, 05:36 AM

Did you check by the fire wall? I'm also thinking that maybe the problem is in the wiring harness I know that they make a kit for that also I have heard that if one doesn't buy a Delco pump you can have tons of trouble even if there new some have even come out bad before or don't last long. Maybe trace your wire back with a test light.

Hang on there is a lot of more members here a lot smarter than me im sure Leo will chime in real soon.

leolkfrm · 06-12-2009, 05:42 AM

Did you scan it? a bad temp switch will make the computer shut things down

z07 · 06-12-2009, 09:40 AM

Quote:

Originally Posted by Emfinger

My question is why and what is the difference between all the models and the 1998 fuel pump $115 for a 1995 to 1997, and $310 for a 1998?

It could be the difference between TBI and MPI. Sequential multiport injection (later tech) requires 40-45 PSI whereas throttle body injection requires something like 15 PSI. The difference in price is a mystery though. JC Whitney, Summit Racing, et al sell out of tank in-line pumps that can be mounted to the frame rail to replace either type of in tank pump for less money and less hassle when and if they fail.

Quote:

Originally Posted by Emfinger

And why dont i have power to my harness on top of fuel pump? Please help me.

You should only get power there durring the first few seconds after you turn the key on via FP relay and while the engine is running via the FP relay and the oil pressure sensing sending switch. Both circuts use the fuel pump fuse(s).

Can you tell us the key position and if the motor was running or not when you checked?

BTW FP relays are often the same relay as other systems. When or if you pull yours to check it, if you look at the other relays right there you may find one for a non-critical system like AC that you can temporarily swap for a test.

Emfinger · 06-13-2009, 05:49 AM

I checked it with the key in the on position and with it running it is hot all the time now.. i definetly will check into the other suggestions thank you. I have owned 3 different chevy/ Gmc trucks and have never had this problem( 89,93,97 ) and had to change the fuel pumps in all of them, im just baffaled??

06-12-2009, 04:32 AM	#1
Emfinger Junior Member Join Date: Apr 2009 Posts: 6	Can someone please answer this?? I have a 1998 Z71 5.7 liter my fuel pump staopped running i checked the fuses and relay, then i pulled the bed and changed the fuel pump with on i ordered offline(pump only). The new pump wasn't the same but i put it in, then i found i had no power to my fuel pump so i ran a wire to it. Now it runs(FP) but it will not start, you can put gas in the TB and it will start you can drive it but not accelerate hard, you can easy into it and go good but if u punch it, it sputters. I changed the fuel filter, and still have the same results. My question is why and what is the difference between all the models and the 1998 fuel pump $115 for a 1995 to 1997, and $310 for a 1998? And why dont i have power to my harness on top of fuel pump? Please help me.

06-12-2009, 05:36 AM	#2
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 4,645	Did you check by the fire wall? I'm also thinking that maybe the problem is in the wiring harness I know that they make a kit for that also I have heard that if one doesn't buy a Delco pump you can have tons of trouble even if there new some have even come out bad before or don't last long. Maybe trace your wire back with a test light. Hang on there is a lot of more members here a lot smarter than me im sure Leo will chime in real soon. Last edited by gmctrucks; 06-12-2009 at 05:38 AM. Reason: add

06-12-2009, 05:42 AM	#3
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,931	Did you scan it? a bad temp switch will make the computer shut things down __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

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06-13-2009, 05:49 AM	#5
Emfinger Junior Member Join Date: Apr 2009 Posts: 6	I checked it with the key in the on position and with it running it is hot all the time now.. i definetly will check into the other suggestions thank you. I have owned 3 different chevy/ Gmc trucks and have never had this problem( 89,93,97 ) and had to change the fuel pumps in all of them, im just baffaled??