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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 1726
Experience:  Owner at DJ Wilson
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2004 Peterbilt mbn single turbo.. I have around 5.5 vacuum

Customer Question

2004 Peterbilt mbn single turbo.. I have around 5.5 vacuum at idle and 8 or a little more when I hammer it. Changed pump changed all the suction lines changed filters. Haven't changed the suction line between water separator and pump yet but did blow it out to make sure nothing. Was in it. Blew out the other return lines.. When I shut off the motor it hold around 3 inches of vacuum and when I loosen the water seperator I here a quick suck then it's gone and the gauge bottoms out at 2.. Tank vents are open and removed the caps to see if they were junk but it didn't help. Any ideas ??
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Daniel Wilson replied 1 year ago.

Hi my name is***** will be glad to try to help. Run a separate suction line to the pump from a separate container or into the fuel tank filler and prime to see if the problem still exists. If so there is a problem between the tank and pump ( Restriction or leaks). What is the complete engine model and serial number and what fault codes do you have logged in the ECM?