david auster

iTrader: (10)

I am about to fire up my new motor, its a miniramed 350 and I set the fuel pressure to 44 psi. When the fuel pump stops priming it drops to about 40 psi. After sitting for awhile the fuel pressure has dropped some more and I am wondering if this is normal or if its supposed to hold constant pressure? I didn't see any fuel leaks either. Also once you prime the fuel system it jumps back to 44 instantly.

Any input would be appreciated

Viprklr

iTrader: (5)

It's normal for the pressure to drop. It's just if it drops too fast that you have a problem.
My car holds pressure within 2 pounds after 15 minutes. After that I figure there is no problem.

DJP87Z28

After you shut down the pressure in the lines will over time drop the pressure to zero. I have a under hood fuel pressure gage.and can check the drop. What you have sounds normal.

david auster

iTrader: (10)

Thanks for the replies,

I just checked it and after an hour its at 30 psi. The fuel pressure does shoot right up the second you prime the system. I just wasn't sure if there was some kind of problem if it drops at all.

Chris89GTA

iTrader: (2)

I'd say you are alright. If it dropped faster I would say you had a problem w/ leaky injectors.

david auster

iTrader: (10)

Today was a long day...That great fuel pressure I was holding all of a sudden let go when I was putting the dist. wrench in place.

I have no idea what happened, but when I primed it, the pressure would go up to normal and immediatly drop. I also could hear a leak but couldn't find it. I took the whole intake fuel system apart and reassembled it and now I get normal pressure and then it starts to bleed down slowly from there. I would say it is bleeding down to 20 psi in 20-30 minutes.

I also tried testing fuel pressure on my buddies TA and it holds pressure steady only dropping an initial 2-3 psi. So I'm stumped as to why all of a sudden I lost all my fuel pressure and now I'm not holding it like I had when I first tested it.