'05 V70 n/a Fuel Pump Check Valve Location

Faust · Post by **Faust** » 04 Nov 2024, 10:25

As mentioned in an earlier post, fuel pressure builds to normal during the usual 5 second run time for the pump. As soon as the pump stops, it rapidly falls to zero. After much inspection I am convinced, I must have a bad check valve. this is an '05 with the steel tank and no external filter. My question? where is the check valve, is it encapsulated in the fuel pump, requiring replacement of the pump? I have heard unfavorable reports of aftermarket in line check valves.

I thought I should add this. The corrugated hose on the pump had developed a pin hole leak. and caused the original problem. I am confident that I patched that. Wrapped it with rubber and put on a fuel injection clamp. High pressure leak no longer visible.

Post by **erikv11** » 04 Nov 2024, 11:56

I also replied in your original thread, probably better than starting a new one.
original thread: viewtopic.php?p=654559

The check valve is inside the fuel pump. If you don't want to mess with inline check valves, the only solution would be to replace the pump.

Faust · Post by **Faust** » 04 Nov 2024, 13:20

Whole story. Can appeared to run out of gas. I had recently replaced the fuel pump with one from my parts car, and had left seat out for easy inspection if things did not go well. Opening it up I found high pressure leak on the corrugated hose on the pump. As luck would have it, I found myself broken down in front of a house where the guy's hobby is antique cars. Together we were able to cut come rubber to wrap the pipe and secure it with a fuel injection clamp. It appeared that the leak had been solved by watching through the floor hatch. Still, car would not start. I had AAA tow it to my house. I then tested fuel pressure and found that it would pump up to around 50lbs, then fall to zero immediately when the pump finished it's five seconds. Then, because it is always recommended, I replaced the pressure sensor with a known good one. No difference. So that is where I am, no visible leak from the pump and a rapid fall off in pressure, so I am thinking check valve. I am not anxious to replace the pump again because the last time the job took almost two weeks before I found the right combination of led lights and mirrors. No way to test PEM, except to substitute a known good one.

Post by **abscate** » 08 Nov 2024, 20:13

I think I have a used PEM but am away until Sunday. Pm me address and I’ll look in the shed

Faust · Post by **Faust** » 18 Nov 2024, 00:13

abscate wrote: ↑08 Nov 2024, 20:13 I think I have a used PEM but am away until Sunday. Pm me address and I’ll look in the shed

Thanks, but no need. I have two "parts" V70's under the barn.

Faust · Post by **Faust** » 18 Nov 2024, 11:11

Still no solution. I have replaced the troublesome fuel pump with a known good one from a parts car. Now the pump doesn't run at all. I assume an electrical problem. I have been offered a very low mileage Lincoln Continental, only 200 lbs. heavier than a v70 and average mpg one mile per gallon better, I may be tempted. If only it had a roof rack for my boat.

Post by **cn90** » 18 Nov 2024, 18:45

Did you swap a good used PEM as a test?

Post by **vtl** » 19 Nov 2024, 07:48

Power your pump directly with 12 volts. If it runs then replace PEM.

Post by **vtl** » 19 Nov 2024, 07:50

If you have VIDA you can also check for fuel pump duty cycle. Good pump is around 35%, they die at around 60%. My is at 47%, and I have no history if it's ever been replaced. 275k miles and almost 20 years seems to be too much for factory installed pump. I have the same 5 seconds problem, btw.

Faust · Post by **Faust** » 19 Nov 2024, 14:40

cn90 wrote: ↑18 Nov 2024, 18:45 Did you swap a good used PEM as a test?

Yes, although since they all look the same covered with dirt, and I forgot to mark them, I don't know which is which.