fuel issue i think.........

envoyhell · 06-16-2008, 04:14 PM

hi gang. new to the site. i have a 99 envoy 4.3 auto 4 door. replaced failed fuel pump with new aftermkt unit along with fuel filter. ran great for 2 days and now its sitting. i unhooked harness that plugs into the pump assembly to chk for power and had none on test light. plugged it back in,turned key and could hear pump run, but it will not start now. now, i had did this earlier in the day(checking power, wiggleing plug etc.) plugged it back in and tried it and nothing,nadda no noise from the pump at all. just tried it an hour ago (3;10 pm est.) and the pump will run, but not start. any ideas, comments, suggestions? need to get this thing going, its my primary ride. thank you all in advance!

Yogi · 06-16-2008, 04:55 PM

Welcome to the Forum! You might get more help by posting this in the 4.3L motor section. You might have a problem with the fuel pressure regulator located on the motor. If the fpr will not hold pressure, the motor can be hard to start. Get a fuel pressure tester and test your fuel pressure with the key on and the engine off (KOEO). Pressure at koeo should be 58#. Pressure should hold at 58# when the pump shuts off after 4 sec.

Sounds like your connector could also be causing the problem. You have a high resistance in the connector which reduces the voltage to the pump. When the starter turns over and the battery voltage drops, you don't have enough juice to run the pump.

Bad fuel pump connectors are a problem area on these trucks. Some fuel pump kits come with new connectors. I would clean the connections as good as possible and clean the ground connection on the frame. If that doesn't cure it, replace the connectors.

But start with the pressure test first.

06-16-2008, 04:14 PM	#1
envoyhell Registered User Join Date: Jun 2008 Posts: 6 Location: User is: OffLine	fuel issue i think......... hi gang. new to the site. i have a 99 envoy 4.3 auto 4 door. replaced failed fuel pump with new aftermkt unit along with fuel filter. ran great for 2 days and now its sitting. i unhooked harness that plugs into the pump assembly to chk for power and had none on test light. plugged it back in,turned key and could hear pump run, but it will not start now. now, i had did this earlier in the day(checking power, wiggleing plug etc.) plugged it back in and tried it and nothing,nadda no noise from the pump at all. just tried it an hour ago (3;10 pm est.) and the pump will run, but not start. any ideas, comments, suggestions? need to get this thing going, its my primary ride. thank you all in advance!
	[Reply w/Quote]

06-16-2008, 04:55 PM	#2
Yogi Registered (Ab) User Join Date: Feb 2008 Posts: 4,093 Location: League City, TX (Houston) User is: OffLine	Re: fuel issue i think......... Welcome to the Forum! You might get more help by posting this in the 4.3L motor section. You might have a problem with the fuel pressure regulator located on the motor. If the fpr will not hold pressure, the motor can be hard to start. Get a fuel pressure tester and test your fuel pressure with the key on and the engine off (KOEO). Pressure at koeo should be 58#. Pressure should hold at 58# when the pump shuts off after 4 sec. Sounds like your connector could also be causing the problem. You have a high resistance in the connector which reduces the voltage to the pump. When the starter turns over and the battery voltage drops, you don't have enough juice to run the pump. Bad fuel pump connectors are a problem area on these trucks. Some fuel pump kits come with new connectors. I would clean the connections as good as possible and clean the ground connection on the frame. If that doesn't cure it, replace the connectors. But start with the pressure test first.
	[Reply w/Quote]