All new Mechanical gauge, big line kit, Draw straw, just tried second brand new Raptor 150 and fuel pressure goes up with acceleration and rpms.

 

I adjusted to 18 psi but the dang pressure drops back and forth between 18 and 15 at idle..... you can time it with a watch, back and forth. Then when you rev it the pressure goes up way too high. Grid heaters are disconnected and I checked with a volt meter for voltage fluctuation but it's charging steadily when engine is running

 

 I switched to a different new raptor 150 today thinking it was the pump regulator... weird... because after you adjusted it to the 18 you get going down the road and the dang pressure goes up  as high as 25.

 

My 02 does not do this........ pressure is steady till you get on it and it drops to about 16 which is normal.

 

Any thoughts....?

Edited May 5, 20177 yr by JAG1

2 hours ago, Mopar1973Man said:

 

WOT will fix that problem.

 

 

I'll keep that in mind next time! Every time I had to get into the fuel lines, but fp gauge would be all over the place for a couple days until it finally settled out.

 Combined with changing the filter 2 times with dirtiest filter I ever saw in measly 700 miles, I'm hoping you guys right.

 

That be nice cause I need a break from truck problems for awhile

Again the difference the difference of a 2 line pump vs a 3 line. It only takes one WOT run down the highway to push the air out on a 3 line pump. 2 line pump can create its own cavitation air. This was documented back years ago with the old stock Carter pumps. A member from over on TDR made a video of how a stock pump could create its own air bubbles by just pump cavitation. 

I think air is also getting trapped in the hand primer pump that's built in above the filter base on the Racor. I need to add a bleeder valve to get that air out, making it also easier to fill any new filter with the hand pump.

 

I also see now how the two line system as I have can create it's own air with a wild gauge from cavitation. I thank you guys for the links and discussion.

 

BTW, remember me saying I can't crack the injector lines loose as the P/O really hammered them tight. So till I get the right size crows foot I found that I can crack open the fuel line to the VP and bleed/prime that way. Never knew you could do that. I guess the VP tends to hold enough fuel when changing filters or just that it is close enough to the return to help itself bleed off the air.

Edited May 14, 20177 yr by JAG1

46 minutes ago, JAG1 said:

BTW, remember me saying I can't crack the injector lines loose as the P/O really hammered them tight.

 

Not a good sign either if the lines or over tighten its possible to distort the high pressure lines tips and the cross over tubes. 

16 minutes ago, Mopar1973Man said:

 

Not a good sign either if the lines or over tighten its possible to distort the high pressure lines tips and the cross over tubes. 

So should I just leave them alone till the time comes to change injectors?

2 hours ago, JAG1 said:

So should I just leave them alone till the time comes to change injectors?

If it isn't broke, don't fix it. 

5 minutes ago, IBMobile said:

If it isn't broke, don't fix it. 

 

Just remember if you attempt to loosen and then there is a leak issue air or fuel then you understand why. 

Might be a good idea to get a can of liquid nitro to spray, make the nut cold and then loosen with the engine warm? Or is that a bad idea? IBM, I promise not to 'fix' until  I have to. Thanks.