EFI Fuel Pressure Issues - Replace Pump?

[Izzy]

I did the Vacuum plug test and it made no difference in PSI. Still only getting between 28 and 30 psi.

I will have to think about how to plug the return line. I have steel lines running all the way back to the tank.

 

[chuzie]

Damn steel lines! So much for pinching.

 

[Izzy]

I was able to do the pinch test on the feed line. I just can't pinh off the return line.

I did the pinch test 2 ways:

1. I pinch the fuel line before starting the engine. Engine cranked over, ran for a few minutes and then the pressure began dropping very low and died.
2. I then unpinch the line and cranked the engine again. Engine ran at 24-28 psi. Then pinched the line again and noticed no change.

 

[chuzie]

Gotcha. We just want to determine your pump's ability to reach and typically exceed 40psi. The only way to do that is prevent fuel from returning to the tank allowing back pressure in the system. When you cap / pinch off the return line, you should see a significant pressure spike. If not, your pump is toast.

 

[Izzy]

ok, That is exactly what I was wanting to hear, a way to test the pump. I will find a way to block the return line and see what happens. I have a 6 an line going into the tank so there's gotta be a way to take that off the tank and block it right?

 

[chuzie]

Your local hose supply should have a -6AN plug available for purchase.

You said you pinched the supply line earlier. I assume it is rubber. Are you sure it is EFI rated and secured with EFI clamps? If not, I would be wary of over pressurizing the system. It will likely be fine but just want to put it out there.

 

[Izzy]

Yes, there is 1 foot of rubber going from the tank to the filter and then it switches back to steel line. It is a EFI rated hose and clamps so I don't think it is an issue. I also ran this in this manner for the last year until experiencing this issue recently. When I installed everything, I was getting the 40psi. Had no reason to test it until recently of course but ti's no at the 28psi.

 

[Izzy]

By the way, thank you for the help Chuzie. I do appreciate it.

 

[xcntrk]

Are you using the BCB braided line kit that can accompany their tank? Comes with the front & rear set of braided lines which interface with their hand-line kit?

Sorry off topic a little, but damn nice kit and I'm considering it...

 

[Izzy]

I just spent 20 minutes on the phone with Wild Horses discussing the fuel pump options etc.

First off, shout to WH for spending so much time with me and validating all the troubleshooting we have done so far. Their customer service continues to impress me.

WH sells a heavy duty pump that is capapble of pushing up to 67 gph. Might seem like overkill but if I'm going to drop this tank again, I want to know it's the last time in a while I will have to do so. The pump is a bit more expensive than the mustang ones but I figured I'm getting a better pump plus I don't mind paying extra to support a vendor who was willing to spend 20 + minutes on the phone with me confirming the issue and troubleshooting steps etc.

It will be a few days before the pump arrives so for grins, I will do the test we mentioned above to confirm the pump is going bad.

Hopefully this fixes my issue and I can move on to the next issue.

Thanks again Wild Horses.

 

[Izzy]

No, I'm not using BC's kit but I built my own so same concept. I bought the pieces from Jegs and built my own lines. I am using BC's hard line kit along the frame though

 

[Izzy]

Quick update. The new fuel pump fixed the problem. It runs awesome again!!! Thanks again to Wild Horses for taking the time to talk through the issue and troubleshooting that you all helped with and getting me the right part to fix this problem. Hopefully this fix lasts for years to come cause i hate dropping this tank

 

[Izzy]

And thanks to everyone on here for helping troubleshoot the issue. You guys are as always very helpful.

 

[xcntrk]

So are you confirming that you do in fact need a larger pump then the stock mustang unit - or do you think a dirty tank caused failure of the prior pump?

 

[Izzy]

I can't say that a larger pump is needed nor can I say what caused my pump to fail but replacing the pump fixed my issue. I can say that the pump that came in the tank did work at one point as the truck ran fine until recently.