Fuel Pumps will not shut off

[1S1K]

So I recently had two Walbro 465 fuel pumps installed to my Fore Hat with return system to make the switch over to e85.
I had the car tuned last Saturday and everything was fine.

The car sat for almost a week due to weather and on the first nice day I drove it around town, stopped at a few places with no issues.

When I got home I heard the fuel pumps running even after the engine was off and the key was removed. Fuel pressure gauge continued to show 38psi. I restarted the engine and shut it off. Same thing, fuel pumps continued to run. The only way to shut them off was to disconnect the battery.

Any idea what would cause the fuel pumps to remain on at all times?

Thanks for any help

Jason

 

[JPM03DSG]

The contacts on the fuel pump relay could have welded themselves together from high current or the inner parts of the relay could have come apart. I've had both happen. Pull the relay under the hood and check across the contacts with a multimeter to see if there is continuity. Might be something as simple as that.

 

[MG0h3]

Gonna have to see how they wired it and what components were used. Pop the trunk and look by the FPDM, that is where everything usually is.

Shoot a pic if you can

 

[1S1K]

The contacts on the fuel pump relay could have welded themselves together from high current or the inner parts of the relay could have come apart. I've had both happen. Pull the relay under the hood and check across the contacts with a multimeter to see if there is continuity. Might be something as simple as that.

I will check that. If that's the issue how do I prevent this from happening in the future?

And is that fuel pump relay located in the fuse box on the driver side engine bay area?

 

[MG0h3]

Yes there is one up there but you must have had some new equipment installed to operate the new pumps on a return setup. Pretty likely that your problem is with the new stuff, not the stuff thats been working just fine for years.

I would suspect one of the new relays failed.

 

[1S1K]

Yes there is one up there but you must have had some new equipment installed to operate the new pumps on a return setup. Pretty likely that your problem is with the new stuff, not the stuff thats been working just fine for years.

I would suspect one of the new relays failed.

Ok thanks. Are there relays located in the trunk also? The return fuel system was on with the smaller pumps. The only thing added was the 465's. They were just soldered in place with the existing wiring.

Doing a little research and came across the CCRM. Could that be the culprit possibly?

 

[bigmoose]

If it's the relay you should get a good post relay, not one of those blade relays. Problem with the blade relays is trying to connect a 8ga or larger wire to it.

I run this without issue:
PAC PAC-80 80-Amp Relay Battery Isolator https://www.amazon.com/dp/B001EAWS6O/ref=cm_sw_r_cp_apa_w77hybQF7XSJ0

 

[KEVINS]

I'm not using the FPDM's anymore and I don't know how your system is wired but I fought this exact problem for 3-4 weeks. I initially was getting the switched 12v power for my pump relays by splicing into the switched power wire feeding the impact sensor in the trunk. Do NOT use that wire for a switched 12V's. Once I ran a wire directly to a switched fuse in the fuse box under the dash the problem went away.

For some reason tying relays into the impact sensor and having the pumps run wasn't allowing the cars relays under the right front fender to turn the power off when the key was removed so the pumps kept running.

If this is how your system is getting it's switched 12v try running a wire to the fuse panel instead.

ks

 

[1S1K]

Anyone think a bad ignition switch could be at fault?

 

[2000GTSTANG]

Anyone think a bad ignition switch could be at fault?

Not unless other things in the car are staying on in the key off position as well.