Intermittent Fuel Pump Problem
12-10-2010, 10:23 PM
#1
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Intermittent Fuel Pump Problem Damn fuel pump wont prime on start up every once in a while. No rhyme or reason, hot, cold, sitting for days or been driving all day it will do it. Replaced the FP relay under the hood same deal. So its either loose wire under the fuse block, a relay/fuse Im missing, or a wiring problem somewhere along the way. Its been so damn long since I put the walbro pump in there I dont remember how its wired up. The pump probably only has 5-6K on it although its about 6 years old 
The truck was sitting without a drivetrain for about 3 years and once I got it up and running everything worked fine(amazingly) after I put about a 1000 miles on it. It did it fairly soon after I got it up and running but after I swapped the relays under the hood it worked fine and just chalked it up as a crappy connection. Then after I got back from a 200 mile trip it started doing this crap all the time.
I really dont want to pull the tank so any suggestions?
FWIW I have a fuel pressure gauge ont eh rail and when it wont start there isnt any rail pressure as soon as the fuel pump rpimes and I get rail pressure it fires right off first turn over.
When the truck doesnt fire off the pump doesnt prime, after I cycle the key until I hear the pump prime it will fire right off so its some sort of electrical issue getting the pump to run, not a FP regulator or injector leak.
I tried searching but the metric **** ton of threads that comes up that have nothing to do with my problem are rediculous.
The truck was sitting without a drivetrain for about 3 years and once I got it up and running everything worked fine(amazingly) after I put about a 1000 miles on it. It did it fairly soon after I got it up and running but after I swapped the relays under the hood it worked fine and just chalked it up as a crappy connection. Then after I got back from a 200 mile trip it started doing this crap all the time.
I really dont want to pull the tank so any suggestions?
FWIW I have a fuel pressure gauge ont eh rail and when it wont start there isnt any rail pressure as soon as the fuel pump rpimes and I get rail pressure it fires right off first turn over.
When the truck doesnt fire off the pump doesnt prime, after I cycle the key until I hear the pump prime it will fire right off so its some sort of electrical issue getting the pump to run, not a FP regulator or injector leak.
I tried searching but the metric **** ton of threads that comes up that have nothing to do with my problem are rediculous.
12-16-2010, 07:51 PM
#2
Not a truck, so I don't know if the fuel pump assembly is the same or not. I have a Racetronix in my car, and I had the same issue. I replaced the pump but the problem continued. Long story short, the connector on top of the fuel pump assembly was melted from not having a tight connection. When I get home I can send pics of the connector if you would like.
12-16-2010, 08:12 PM
#3
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That would be great. As I understand it the truck return style fuel system is almost exactly like the fbody fuel syste, which is why I was hoping someone on here had a similar problem. The FP relay is kicking on under the hood so I know everything is good to that point, so it has to be a wire/connection or the fuel pump itself. Once I get some more time to diagnose it(after the first of the year) Ill try and find the wire on the framerail and see if its getting power. Then Ill know Ive got to drop the tank or pull theb ed. It will be a good excuse to finally put the dual pumps in there I need to.
12-17-2010, 12:43 AM
#4
Pics:
http://img139.imageshack.us/i/photovf.jpg/ < This is connector on top of the fuel pump assembly
http://img30.imageshack.us/i/26551080.png/ < This is the part circled
http://img40.imageshack.us/i/img0111gv.jpg/ < This is the connector from the fuel pump, to the top connector on the fuel pump assembly
Hopefully this helps you. All my relays were working properly under the hood and even back by the tank. Some days the car would run fine, others it would die on me while driving it. Loosing power steering going around a corner was not very fun lol.
Chances are I didn't even need to buy a new Racetronix pump. By the time I fixed my problem the old pump was already at the dump.
Otherwise I probably could have got some money back on here for it.
http://img139.imageshack.us/i/photovf.jpg/ < This is connector on top of the fuel pump assembly
http://img30.imageshack.us/i/26551080.png/ < This is the part circled
http://img40.imageshack.us/i/img0111gv.jpg/ < This is the connector from the fuel pump, to the top connector on the fuel pump assembly
Hopefully this helps you. All my relays were working properly under the hood and even back by the tank. Some days the car would run fine, others it would die on me while driving it. Loosing power steering going around a corner was not very fun lol.
Chances are I didn't even need to buy a new Racetronix pump. By the time I fixed my problem the old pump was already at the dump.
Otherwise I probably could have got some money back on here for it. 