sallyman1

According to my quad LP gauge (i dont use rail anymore) when i turn key forward my LP sings until PSI is between 7-9 psi. Then i turn key backwards so i can just view the quad (no LP running) and i can see my numbers go 5, 4, 3, 2, 1 in about 5 seconds. Is it normal for fuel pressure to drop that fast before it gets to the CP3? obviously overnight itll drop off but why so fast and i cant see any leaks.

Pooter

The fuel pump only primes, then cuts out when starting.

From what ive heard, its to prevent rough starting?



Either way, its normal. I put a fuel pressure guage in just to watch my stock LP till I get around to installing a walbro, and it does the same thing, turn key, goes to 6psi, then drops off to zero, and as soon as the truck is started jumps right back up.

sallyman1

cool. thanks.

DieselBoy20

I think power is being cut off to the guage for a few seconds while cranking the truck over and then recovers back to normal operation when truck is finally running. Just like the radio cuts out when being cranked over. Or I could just be full of myself and way off topic.

87BRGN

FWIW, If I leave the key on(not start) till the AD stops running, my gauge will drop from 19-0psi in 2-3 seconds.

Spooler

It is normal. The CP3 has a return on it to the tank for unused fuel, that is where it goes because it is not requiring any fuel, back to the tank that is.