Engine/Transmission (1998.5 - 2002) Fass pressure/ engine idle question

[Hobart]

When I'm warming up the engine it makes a clicking sound and speeds up a tiny amount then another click and slows down a tiny bit. The Fass pressure
drops or rises accordingly about 2lbs. Ive also noticed the Fass pressure is running about 2lbs lower than when I installed it 8 months ago. And doesn't seem to be effected by changing the 2 filters.

 

[Midnite]

Sounds like you're hearing your grid heaters cycle. The clicking is the relay tripping, and the engine slows down when the heaters turn on due to the load on the alternator. When the heaters turn off, the load is removed and the engine speeds back up.

The FASS is affected because it's an electric pump. You probably also see your lights dim, and if the fan was on you'd hear it slow as well.

Completely normal.
Mike

 

[JCyrbok]

Sounds like you're hearing your grid heaters cycle. The clicking is the relay tripping, and the engine slows down when the heaters turn on due to the load on the alternator. When the heaters turn off, the load is removed and the engine speeds back up.



The FASS is affected because it's an electric pump. You probably also see your lights dim, and if the fan was on you'd hear it slow as well.



Completely normal.

Mike

Exactly what he said



As for the PSI being lower you can stretch the spring alittle, behind the bypass fitting on the FASS (the one that has the hose running back to the filler neck). Just becareful not to lose the check ball. Just a little stretch will change the PSI.



Likley there is nothing wrong with the pump, its just the spring taking a "set".

J-

 

[DIESELWRKS]

in the last 2 years during the colder months I get about a 2-3psi raise in pressure. spring and summer it drops. something to think about

 

[JCyrbok]

in the last 2 years during the colder months I get about a 2-3psi raise in pressure. spring and summer it drops. something to think about

yep I get the same, mine is usually about 1-2 psi.



J-