FlatBlack

I've got a 1999 LM7 in my 240SX. I've been driving it for nearly a month with no real problems except when I drive it for about an hour or longer. It doesn't want to hot start.

I put a fuel pressure tester on the car yesterday on the drive home, and I think it's doing some weird stuff off-throttle.

Driving on the interstate the pressure is about 50. If I go WOT in 5th, the pressure jumps up to 60ish, then goes to ~48 when I let off the throttle.

I've seen some other fuel pressure videos for LS1 swaps and they normally are higher at cruise then drop a bit under throttle. This is what my car does at idle.

Maybe my FPR is bad or my new Walbro (Installed early January) is weak?

garys 68

iTrader: (1)

Just curious if you're having tank pressure issues due to incorrect venting or evap system.

FlatBlack

Ohhh... that makes sense if the pressure is building up. I'll check that tonight.

Russ K

iTrader: (1)

Normal pressure as you have a vacuum referenced fuel pressure regulator. So under load you will have more fuel pressure then at no load.

How long does the pressure hold after shutting off the engine?

Russ Kemp