Engine/Transmission (1998.5 - 2002) fuel pressure reading

[jtisdale]

I just got my gauges in yesterday, and everything seems to work great. I replaced the schrader valve banjo bolt (on the pump) with one of Rays tapped to accept the fuel line. Was that a good place to pick up my reading? I get 13 at idle, 11 at cruise, and 5-7 WFO. This is acceptable, right?

Thanks, Jim

 

[fox]

I think the minimum is now at 8 psi wide open. I hate to give bad news. Have you changed the fuel filter?

fox

 

[jtisdale]

Bummer

Yep, I just put a fuel filter in when I installed the gauges.

 

[Idaho Native]

Went to change my filter this weekend and couldn't get the lift pump to "reprime" the filter cannister. Dejuiced the truck externally (see sig) yesterday evening for a trip to the dealer for the warranty replacement.



They tested it and found it putting out 2psi max. They couldn't believe how good it ran... their first phone call to me this morning was that it was working fine, but then upon further investigation, they said it was not functioning. Briar Hopper's gauge was correct



The service rep and mechanic said that if all of them ran as good as mine, they'd sell a million of them The new pump will be in this Wednesday... wonder how it will run then?



Loren

 

[jtisdale]

I may have posted too soon. Now I am also suffering from EFPS (eratic fuel pressure syndrome). Idle is 11-12 , cruise is 9-10 and WFO is 5-6. The gauge bounces wildly within these pressures. Is that common for a fuel pressure gauge? Could there still be air in the fuel system? I have primed the system (with the key), and I have bled the fuel side of the isolator several times each. I think I am going to put the schrader valve banjo bolt back where it belongs, and move my port for my fuel pressure reading to the bottom of the fuel filter to get it away from the injection pump. Any other thoughts????

 

[D White]

jtisdale,

Did you use a lenght of hose to mount the sender away from the motor,, grease gun hose or whatever?? If so, there may still be air in that. Loosen the sender to hose connection to bleed any air in the hose. Mine were irregular till I did that. Mine are close to your readings, 12 idle, 9 cruisin, but 7 to 8 wot.



DW

 

[RBSOB]

Pressure #s

jtisdale, my #s are about identical to your's and DW's, but no fluctuation. I also read pressure at the injection pump but remote mounted the sender unit with approx. 20 inches of fuel line. I never bled any air during install. I believe your pressures are acceptable [mine have been steady at this level for about 6 mos. ] but the fluctuation is not normal. Before relocating, check your ground connection first then bleed for air. Use a good test light or volt meter, I'm betting on a poor ground, easy fix . By the way, I like the injection pump tap, I want to see what the pump "sees". Have Fun and let us know the solution, worst case would be a bad sender, Jim G.

 

[jtisdale]

if it was that easy

I used an all mechanical gauge with an isolator (no wires or sending units). Now I wonder if I should have went with electric. I'll bleed the **** out of it some more and let you know. Thanks again.

 

[Steve Campbell]

Two choices...

Add that 18" of hose before the isolator or add a second isolator to the "system" to get rid of the erractic behavior.



Just My Opinion

 

[jtisdale]

no luck yet

I bled the fuel (at the isolator) out again. I get a nice steady stream from the bleeder screw that is located at the top of the isolator. The fluctuation is as bad as ever, and possibly getting worse. I think it is a bad pump. I noticed when I bumped the key to bleed the line, the pump would vary in speed and pitch. I was under the impression these pump were a single speed. Does the lift pump run all the time the engine runs?

Steve-

This is my set up... Rays banjo at the pump to a straight fitting connected to 30" ss braided line to the isolator mounted to the fire wall as high as I could get it. From there the line with the "fluid" (another ss braided line) goes down to the hole where the hood latch cable passes thru the fire wall, then under the dash and up to my gauge. All hardware was bought as a set from Autometer.

When pumps go bad, will these gauges show eratic behavior as I have described? Also, when I prime it with the key, it goes to 14 and stays there until the pump shuts off, and the it drops to 0. The only time it is eratic is when the engine is running.

Thanks for the help...

 

[Shovelhead]

I think a post a few weeks back another member stated that he experienced the same effects while picking up fuel pressure at the injection pump.

Can you move the pick up point to the filter?

There was something about the rapid variations of pressure caused by being too close to the injection pump.

 

[Huntmastr1]

I recently installed a Westach electric fuel pressure gauge. I installed Rays tapped banjo fitting at the injector pump, ran about 24" of hose to the sender I mounted on the firewall.

Pressure are perfectly smooth:

11 PSI idle

9 PSI cruising

4 PSI WOT.



Went to the dealer and told him my gauge was showing low fuel pressure at WOT. He checked it and agreed. They replaced the transfer pump under warranty (47K miles). OBTW, they did this while I drove the sales managers truck to get lunch

12 PSI idle

10-12 PSI cruising

9 PSI WOT



I have a great 5 STAR dealer!!!!! 3rd truck from them and has always been 5 STAR service.

 

[Chipstien]

I suspect that the odds of it being a guage are nill. Eratic pressures are a lift pump going by by. When the needle starts bouncing it is only a matter of days till the pump takes a dump. `

 

[jtisdale]

I agree

I just put the schrader valve back where it belongs. While moving Rays tapped banjo to the bottom of the fuel filter *SNAP*... oops, that must have been 19 ft lbs. :-laf I went back into the garage and got the easy outs... long story short... The truck is back together-running fuel pressure gauge not hooked up, more parts on order.

I think you guys are right about the lift pump going. I had a **** of a time getting it to reprime, I know it took at least 45 minutes. Time to exercise my warranty:{

I'll let you know what happens.

 

[Summit]

spaztic fuel pressure

jtisdale, i have the exact problem with my auto meter mechanical f-p guage. the only time it used to go "nutty" was when my truck would buck, stumble, does it ALL the time now with a 2-4lb presure variance. most of the time its so bad its just a red blurr. the only time its not as bad is when i downshift while coasting. i started on the vp-44 to much pulsation so went to bottom of filter can, now i am pre-filter and its as bad as its ever been. my vp-44 makes an awful noise, just dont sound like other trucks. about a month or two ago was when fuel preesure started to get worse and thats when my clutch stopped slipping so i know that im down on power. 100hp injectors and comp in EZ mode and no more slippage.

 

[Joe Mc]

Jtisdale - I thought all was fine till I got BriarHoppers test gauge. 8 @ idle, 4 @ cruise and 0 @ WOT. After dealer replaced LP (@ 93k) 16 @ idle, 12-14 @ cruise (depending) and WOT never below 10



Get a new pump then install gauge line post filter.

 

[jtisdale]

Briar Hopper

I talked to Briar Hopper today, he's gonna warp drive a test gauge to me. Really nice guy. I'll get this figured out yet.



-Summit, did you get your gauge problem figured out?

 

[Summit]

FUEL PRESSURE DILEMA

actually stoped at B-DOG today and agreed to try a new lift pump. will try to install by sunday p. m. will post findings . does this sound like the same problem?? whats the part # from cummins? or i'll do a search.

 

[RobbyRam]

Just got my truck back from my dealer(Swift Auto World-Sacramento) Showed them pictures of my Fuel pressure gauge at WOT -3 1/2 PSI. They replaced my lift pump along with a defective MAP sensor and now the truck Idles at 15psi. They did it all for free(70K miles).

 

[duaneparks]

Originally posted by Huntmastr1

I have a great 5 STAR dealer!!!!! 3rd truck from them and has always been 5 STAR service.

Just out of curiosity, where do you take yours? Ron Carter?



I've had great service from Archer Dodge in Stafford myself. . FWIW. I would like to know there are other options out there, though.



Duane