FALCON

iTrader: (1)

I currently am waiting for my 1999 M6 Z28 (H/C/I,Walbro,30# ford injectors) to get tuned and the tuner is having a lot of trouble dialing it in. After three weeks he calls me yesterday and tells the fuel system in operating at 68psi. He is going to inspect the fuel pickup in the tank, does any one have any suggestions or advice on what to look for? Thanks in advance.

Lonnies Performance

iTrader: (16)

It should be 58. You did not mention the pump type used in the car as some aftermarket pumps raise the idle pressure. Is it 68 all the time or just at idle?

Typically it is 1 of these:

Too big of a pump for the regulator to properly control.
A gauge reading improperly
A bad regulator
A crimped return line

FALCON

iTrader: (1)

My tuner is stating it is 68 psi all the time. The pump is a new Walbro 255 lph gs340 pump recently purchsed from Lingenfelter.

FALCON

iTrader: (1)

I have a Walbro 255. I checked with another gauge and it still reads 68-70 at idle and drops a few psi when I rev it. I also replaced the regulator last month. I am having trouble getting it tuned properly. It surges when idling, needs to really warm up or I have no power at low RPMs and it bucks when when decellerating in gear. I get a strong fuel smell when I start it and get around 10 mpg (H/C/I, headers M6). How could I check the return line. I made access panel so if I need to open the tank it is not a big deal. Thanks in advance.

madmax4499

iTrader: (3)

your going to have to look at every inch of it. you could disconnect it at the tank, put the end in a bucket and start the car you should get a decent amount of flow, blow some air thru it. high fuel pressure will make it run as you described.

bravolistick

I think you have some restiction in the line. It may just be air. When setting my stealth pump up, when I initially cranked the car my fp was high also. But the more I drove/cranked the car, the pressure came down until reaching the desired 58psi @ idle. GL