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.

 

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.

 

cool. thanks.

 

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.

 

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.

 

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.