fuel pump PROBLEM

mike knight · #1 (**permalink**) 09-04-2006, 09:51 AM

I am running a weldon 2025 pump. I replaced it because the motor was making a grinding noise but still maintained pressure. Upon inspection the brushes were worn and as it was a used refurbished pump I decided to buy a new pump. I upgraded the wiring and all was fine with the original, at first so was the new pump. yesterday while driving the engine quit with no warning. I was lucky in that I just coasted into an empty bank parking lot. The engine cranked fine but wouldn't even fart. Oh yeah, full tank! Since I had just replaced the pump the rocket scientist in me said hmmmm. I checked the fuse in the trunk and sure enough it's blown. Replaced the fuse and badabing she's running fine, only problem is the pump won't shut down with the engine off. I drove the car around the hood' to see if the fuse would blow again. Engine ran fine and the pump was fine. There is a relay in line with the fuse could this have blown causing the fuse to go, and now is not operating with the ignition switch? I am not an electrical kinda guy, finding the blown fuse was a red letter day for my electrical acumen. The car is an SPF and has been running good.

m

lineslinger · #2 (**permalink**) 09-04-2006, 10:13 AM

Sounds like a ground fault somewhere within the fuel pump circuit, or a short in the relay (the relay quit and is now possibly stuck in the on position) , thus the change in "behavior" since the pump change.
Can you compare the amperage and voltage requirements between the two pumps, if the new one you installed requires more "juice" (amps or volts) it affects the entire circuitry before it.

Tommy · #3 (**permalink**) 09-04-2006, 10:15 AM

Quote:

Originally Posted by mike knight

I upgraded the wiring

What upgrades did you do? If the pump runs continuously with the power off, something is not wired right.

mike knight · #4 (**permalink**) 09-04-2006, 12:55 PM

We ran new 8 gauge wire replacing the original wiring exactly as it was factory installed. The original pump was functioning perfectly except for the buzzing sound which was the reason for changing in the first place. The pump was working per spec until the engine quit. I then discovered the blown fuse. Coincidental to the blown fuse is the pump running even with the ignition off. Since the engine quit abruptly and fully I can't determine the chicken or the egg. When I plugged in the new fuse the pump came on with no keys in the ignition and will not stop until i pull the fuse.

mike

jarendall · #5 (**permalink**) 09-04-2006, 01:27 PM

if you have a relay for the pump, check for the contacts being stuck, sometimes in an older relay the contacts will arc and stick togather, also does the pump have an internal pressure switch, instead of a relay, if so, check to see if the pump is actually pumping, if not pumping, are you out of gas

Rick Parker · #6 (**permalink**) 09-04-2006, 02:08 PM

Your relay is bad. The buss bar inside is "welded to the 2 posts" internally. Or you have connected wires to the incorrect posts on the relay (if that was involved in your upgrades).

Tommy · #7 (**permalink**) 09-04-2006, 02:41 PM

I'm not much of a believer in coincidences. I find it hard to believe it was a coincidence that your relay failed at the same time your fuse blew and you had just been working on the wiring for that system. Look for a reason beyond coincidental failure of a relay, IMHO.

mike knight · #8 (**permalink**) 09-04-2006, 03:29 PM

Solved! the relay is bad. I don't know why the pump ran for about 2 hrs before the fuse and the relay went, but that was it. I found a napa store that was open today until 3:00 and they had one in stock. I think I'll buy a couple more for any additional coincidental problems.
TOMMY, I'm with you, I don't believe in coincidences either. Hopefully this was just an anomaly and I can start playing again. If this pops then I'll start from scratch.

thanks all for your thoughts.

mike

Jim Norris · #9 (**permalink**) 09-04-2006, 04:16 PM

Mike,
I'm glad you solved your problem. I had the same sort of no warning shut down happen to me. I was also able to roll into a parking lot. I too replaced the fuel pump. I could not hear it running after my shut down, so I figured it must be bad. I did not replace the relay however.
Where is the relay physically located on your SPF? Under the hood or under the car?

mike knight · #10 (**permalink**) 09-04-2006, 06:13 PM

Jim, I put in a relay, independant wiring and bypassed the dash switch for the fuel pump. I now use the dash switch for the turbo intercooler pump. The relay has a dedicated 30 amp fuse adjacent to it. If you want I can give you the relay part number. It is manufactured by Hella. I bought it at Napa autoparts in the Chicago area. If you don't have a napa near you I'm sure you can cross reference the part.

Jim Norris · #11 (**permalink**) 09-05-2006, 09:56 PM

Mike,
Thanks for the info. I was worried that there might be another component at the root of my apparent fuel pump problem. I'm more convinced now that the pump has to have been the problem. So far so good.