Checking Fuel Presure
04-30-2003, 10:55 PM
#2
Registered User
Re:Checking Fuel Presure
You need a fuel pressure gauge. It might be possible to borrow one from Autozone if you have one near you because they have a loaner tool program and hopefully loan pressure gauges.
Once you get it, there should be adapters in the kit. Remove either of the test plugs from the top of the fuel filter housing and connect the gauge there. The plug closest to the front/right/inside is post-filter and the one to the rear/left/outside is pre-filter. You'll want to check both as the filter can absorb as much as 6 psi of fuel pressure.
The part that sucks about this is you need to have a long hose on the gauge (some don't have it) so you can snake it up between the hood and the cowl so you can go for a drive. The pressure might be OK idling but cruising or WOT it may be bad. This happens frequently.
Less than 8 psi at any time is replacement time, per Cummins.
CAUTION: When I pulled my test plug to check fuel pressure my pump was already bad (0 psi) and pulling the test plug disturbed the "vacuum" the VP44 had, that kept the engine running. I'm not saying don't check the fuel pressure, just be prepared in case yours is bad already. This means don't do it just before you need the truck and park the truck in a good place for the tow truck to hook up to it if you DO need a lift pump. (Dodge will pay for the tow)
Chris
Once you get it, there should be adapters in the kit. Remove either of the test plugs from the top of the fuel filter housing and connect the gauge there. The plug closest to the front/right/inside is post-filter and the one to the rear/left/outside is pre-filter. You'll want to check both as the filter can absorb as much as 6 psi of fuel pressure.
The part that sucks about this is you need to have a long hose on the gauge (some don't have it) so you can snake it up between the hood and the cowl so you can go for a drive. The pressure might be OK idling but cruising or WOT it may be bad. This happens frequently.
Less than 8 psi at any time is replacement time, per Cummins.
CAUTION: When I pulled my test plug to check fuel pressure my pump was already bad (0 psi) and pulling the test plug disturbed the "vacuum" the VP44 had, that kept the engine running. I'm not saying don't check the fuel pressure, just be prepared in case yours is bad already. This means don't do it just before you need the truck and park the truck in a good place for the tow truck to hook up to it if you DO need a lift pump. (Dodge will pay for the tow)
Chris
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