Fuel pressure test procedure m60

[drken]

Bentley doesn't specify whether fuel pressure regulator vacuum source is connected or disconnected for fp testing. I get 44psi with it connected, and 51 psi with the hose off, and vac plugged. Manual calls for 51, but I don't know if I am testing correctly.

Anybody?

Thanks!

Ken

[drken]

Think I figured it out. The Bentley manual specifies jumping the fuel pump relay to power up the fuel pump without starting the engine. Since engine is not started, vacuum doesn't affect the fuel pressure. Doing this, I got the specified 51-52 psi. Just an FYI in case anybody is searching for this in the future.

Ken

[Aleksey]

Yup, you got it.

Your intake vacuum affects pressure, the tests should be done with it off to get reliable readings.

I wrote about this here: http://www.e34addicts.com/Checking_Fuel_Pressure