rebar

Unfortunately, MSC only offers the above tubing in 100' rolls.

When I asked them to recommend tubing that can be sold by the foot for my diesel fuel pressure gauge they recommended rubber first. Then Polyurethane Tubing..
I found someone online who said "I tried the blue polyurethane line last year on the small engines I maintain at my job. It has been an abysmal failure."

So even though they sell allot of good products, there tech guy needs some education and I'm still at square one.

patdaly

You might want to peruse McMaster-Carr, always been my go to place, fast shipping as well:

https://www.mcmaster.com/standard-pl...-rubber-tubing
https://www.mcmaster.com/8359k11

rebar

Perfect! And these fittings.

https://www.mcmaster.com/50915k311

rebar

It always happens.. I fell down the internet hole and found this discussion after mcmastercarr wouldn't give me a shipping quote.

And I'm believing KATOOM when he says 1/4" line will transmit less noise vs 1/8"

Air brake line should be easy to find locally and my shop has plenty of 1/4 Compression Ferrule fittings..

rebar

Looks like I have what I need now finally. I'm real curious what my fuel pressure is. Might have to cut the project short though because this maybe the last warmish bike riding days left this year..

Got the bikes cleared out and tested the gauge. I cant believe how much the line and gauge shakes.. over 10 psi idle

.
.

patdaly

Definitely low fuel pressure there.......... 25-27 at idle with a P7100

rebar

Thanks Patdaly.

Does that definitely mean I need a new lift pump? Or could the overflow valve cause the lower pressure, or something else?

And should I stop driving it that low?

texasprd

The gauge shouldn't shake that much. If you have a needle valve, close the needle valve down until the gauge steadies. Bad OFV and bad lift pump can both cause low pressure. To test the OFV, briefly clamp the rubber part of the return line to the tank (where it runs behind the fuel filter). If the OFV valve is bad, pressure should increase. You can do this at idle. but the test is more effective if you do this with the engine at 1500 or 2000 RPM. If the pressure doesn't increase, the lift pump is bad. In that case, replace the lift pump and repeat the clamp test to then check the OFV with a good lift pump. With a good lift pump and the return line clamped, pressure can easily shoot up near 60 PSI with the engine at 2000 RPM.

rebar

I clamped the return line behind the supply and gained maybe 2 psi at idle up to 14psi.

Anyway, looks like I need a new lift pump. This is a bad time because now I'm on foot, with my other truck down getting a radiator built.

rebar

Turns out my pinch off pliers didn't pinch the return line tight enough.. Once it was pinched, I got 40 psi easy.. Its my ofv.

Does anyone know about stretching the ofv spring before I receive my Tork Tek ofv?

rebar

I removed the overflow valve and recorded the base line 20 psi air pressure it took to crack it. I then added a ball point pen spring cut 1/16 longer than the stock spring and installed it inside it. It took 40 psi to crack it and initially I thought it was to high but its running 25 psi idle and >30 at 2000 rpm. I plan on getting a new tork tek OFV020, but knowing I'm in the recommended low pressure fuel pressure range makes me feel better.. Its easy to be fooled into thinking you need a new lift pump because pinching the return line isn't easy..