O.K. guys. My fuel pressure starts at 60lbs and at about 4600rpm, it starts going down, to about 56lbs at 5600rpm. My ? is this, does anyone else have this problem? Remember my truck does not have a return line (2004 and newer). Westers is saying this is the reason I am getting pinging at 4600rpm and higher. I also have the walbro 340 pump and it helped because it was starting at 58lbs and going down to 49lbs before I put the walbro in. This is driving me crazy.

thanks for any ideas

 

sorry for thread jacking but Im kind of having the same issue with mine. Although I havent checked fuel pressure yet. Ive noticed on the WB that its going lean higher in the rpm I go and start getting som det. a/f goes from like 11.2 and leans out to 12.2 - 12.4 before it shifts. Never had this problem before I think the pump is getting weak. Im installing a hot wire kit and walbro 360 inline pump, hopfully it solves the issue. Also noticed yesterday truck died a couple of times at start up and was idiling kind of choppy. drove it around the block and was woring better.

 

The small drop in FP is normal with the returnless systems as the regulator is way back in the tank(line pressure drop). You may need larger injectors if yours can't keep up at the lower pressure. On returnless systems the injector flow rate needs to be scaled in the tune to compensate for the pressure drop.

 

Check the FP. Also check that your FPR on the fuel rail is functioning properly and that the vac line to it is dry inside. My Walbro is over a year old and it is starting to lose pressure more and more at high RPM. Not sure if it is the pump or if I have sprung a leak in the intank plumbing. So far the 60's have been able to compensate, but I'm going to have to drop the tank soon.

 

DrX, Did you get a kit to make yours into a return style system? Where did you get it?

Thanks

 

I had the same identical problem. I lost 4lb's of fuel pressure in 3rd gear under full boost. Are you still running with the stock fuel size line? I installed a second stock intank fuel pump and increased my fuel line size from each pump to -6 and then ran that to a Y block which I ran a single -8 to a boost referenced fuel pressure regulator with a -8 ruturn to the tank. From the fuel pressure regulator, I ran 2, -6 lines to the fuel rails. One to each. That solved all my problems.

 

Ok check fuel pressure. idle is about 54 psi. stab the throttle, pressure spikes to over 60 and falls back to 55 under WOT. Does this sound like pump is not keeping up?

 

WJ MARK, You have a return style system, correct? I'm trying to find out about the returnless system. Anyone else have this problem with a 04 or newer?

 

I had a deadhead, returnless system to start with. Just not enough volume to sustain it.

 

Do you have any way to send Lyndon logs?
A small pressure drop is normal like said before. Before I swapped to 60lb. injectors and the Magnavolt my pressure would drop from 64lbs (per gage) down to ~57lbs.