Engine/Transmission (1994 - 1998) Low fuel pressure questions

[jsjaastad]

1995 bone stock 5 spd. 90,000 miles.

Made a fuel pressure tester like the one Signal73 (05/01/06) posted pictures of cause I was just curious. The truck ran okay but was kind of listless while accelerating. My manual says to check the pressure at the fuel drain manifold. I did it like Signal73 did at the fuel supply line at the injection pump.

Idle = 9#; 2000 rpm = 10#. I installed a new overflow valve and tested again. Idle = 14#; 2000 rpm = 18#.

New filter, idle = 19#; 2000 rpm = 20#. At full throttle it will gradually increase to 27#. Manual says mininum fuel pressure is 25# but does not say at what rpm you should test.

Does it make a difference if you test before or after the filter? Do you think I have a problem with the lift pump?

I replaced the plunger O ring on the primming pump with one I had, not the Dodge one.

Any help or advice will be appreciated.

Thanks, Tom/Idaho

 

[bmoeller]

Fuel Pressure: 18-24 psi at idle, 28-36 at 2000 rpm with no load.



It could be the lift pump. They last a long time, but do fail from time to time. Nothing like a 24v lift pump.



I would check after the fuel filter. Will be a little pressure drop across the filter.



Have you cleaned/replaced the fuel strainer?



http://dodgeram.org/tech/dsl/filter/pre-filt_clean.htm

 

[Joe G.]

You could have a slight air leak. That will drop pressure, but it will still run ok. If the problem gets worse an air leak will make you walk. Read this:

http://dieselram.com/ubb/ultimatebb.php?ubb=get_topic;f=45;t=000007

 

[jsjaastad]

bmoeller,

It has been awhile since I cleaned the fuel strainer. I will do it again.

Joe G. Some time ago the primming pump started leaking past the plunger. I replaced the O ring with one that I had. Perhaps I should get the correct one (if possible) from Dodge ? Or do I have to buy the whole lift pump? Also, I tried to open the link you suggested and the computor keeps telling me I am not logged in and can't open it..... It's obvious I am logged on.

Thanks I appreciate any and all help. Tom/Idaho

 

[Joe G.]

You should have access to that forum (it's not TDR) with no problems. I wrote that up at the request of the web master of that forum. If it refuses to let you access the post on that link, sign up for the forum. It's free. It saves me a lot of repetative posting if I refer to that write up.



I don't think the O-ring for the push button could cause your problem. I am using a O-ring I got a NAPA. It's a close match to the stock one that was leaking.