fuel press test

[crazygn]

Ive had a problem for about 8 weeks that i can not find, the car has no top end power any more and does not like to rev over 4800.

I did the leak down test today and the fuel press will not hold long, it starts at 40lbs i let it set and 6 mins later its at 0. I did this 3 times and the most it would hold was 10 mins.

could this be my problem , should i drop the tank.

thanks guys

 

[GNSS]

IMHO, I wouldn't worry so much about how long it stays under pressure after it's shut down. I've had different pumps and regulators and they all respond a little different. Just make sure you have the correct pressure under boost .
Perhaps it's your valve springs that are weak and not allowing it to rev past 4800. Also might want to check the lift of the cam lobes.

Jeff

 

[crazygn]

i put some pliers on both fuel lines , the feed line and the return line to see if the injectors or the reg where leaking. It seemd to hold 40psi but then when i took the pliers off it droped to 20psi right away, does this mean that something could be wrong with my pump or the check valve in the pump, its a 307 pump thats about a year or two old.


what do you think, the gnttype says that it should hold for at less 20mins.

 

[crazygn]

If iam running 41 psi fuel pressure with the vac line off and 17psi boost then how can i have 61psi on my fuel gauge under boost. It should be 58psi under boost right.


I also closed the fuel lines up before and after the reg and fuel rail , it seems to hold pressure but when i let go of the lines it drops from 40psi to 20 psi. Could this be the check valve in the pump should i drop the tank. It will only hold pressure for 6-10 mins.


help

 

[frankg]

The leak down thru the pump may be a problem not sure never checked that? But, when was the last time you've changed the fuel filter? Air intake system is clean? Exhaust system isn't clogged? It may be a good idea to pull the valve covers and check your valve springs and have someone crank the engine over while you watch to make sure no cam lobes are wiped. Is the car popping or going lean on your scan tool? Thanks,Frank

 

[REDS HOT AIR]

only let go of one fuel line at a time if you release the return and it drops then you know its leaking thru the regulater and if its the feed line then you know its in the pump