Engine/Transmission (1998.5 - 2002) Lift Pump testing confusion?

[Renoram]

I just took my truck into the dealer because it was slow to accelerate or bogging down when cold- it clears up after 15 to 20 minutes of driving. I didnt think it was the lift pump because I had a solid 12-14 psi on my gauge- never goes below 8psi at WOT. The service rep said that i had a hard code lock for the LP & possible APPS. He said that he then did a fuel flow test & the fuel flow test failed at 30 ounces in 30 seconds & normal is 52-56 ounces/30 seconds. They wanted to change the LP & APPS to start. I have almost 80k miles on it & the service rep says that I got a lot of service out of this LP as it is. He says that they see this all the time & change a lot of LP's.



I decided to install the FASS system instead & have it on order. Just to confirm my fuel pressure gauge was reading OK, I bought a mechanical direct test gauge & confirmed that my guage was correct. Has anyone heard of this method of testing? The service rep said that the mechanic said that this is how they test the LP & doesnt care what the fuel pressure is. He said that if I wanted my fuel pressure tested, he would charge me another half hour labor. This confuses me as all the reading on the forum talks about fuel press & not flow.



Does anyone know how to do this fuel flow test? I dont have a factory service manual. I plan to do this test before & after installing the FASS system.

 

[Tcolesanti]

Yes, the dealers use a feul flow test, not pressure. There is no need to do this test with the Fass installed. It flows a ridiculous amount of fuel, most of which is returned to the tank. Inlet pressure at the Vp 44 is extremely important too, which is weird that the dealerships don't do that. What I'm trying to say is that the Fass flows so much more fuel than a stock pump at the same pressures(about the same) that you really would be wasting your time trying to test it that way. Hope this helps.

 

[DCTECH]

Cummins/daimler-chrysler Changed Testing Procedures For Lift Pump(transfer Pump). No Longer Concerned With Pressure. Measure Volume For 30 Seconds, Has To Be A Minimum Of 46 Ounces And No More Than 5 Psi Pressure Drop Across Filter. Aslo No More Than 5 Inches Restriction On Suction Side. Per Tsb 14-02-03.

 

[GeorgeW]

Renoram,



I was in the Dodge dealer in Salida, CO for another problem (cracked exhaust manifold) and the tech offered to test my LP just for kicks. He said that when the starter is bumped - without starting the engine - the LP will run for 20 sec and specs say that it should flow 44 oz of fuel during that time. He disconnected the fuel line going into the injection pump from the LP and let the fuel flow into a bucket which had volume marks on it. My LP put out 48 oz so he said it was ok. By the way, the LP pressure shows 12 psi at idle and 10 at cruise.

 

[Murle]

You will love the FASS. Been running mine now for almost a year... . Would not have another Dodge without one. Also you might look into Marco's CaTHER ECM if you want to see what a real diesel will do. These 2 modes I will never be without.

 

[Renoram]

Cummins/daimler-chrysler Changed Testing Procedures For Lift Pump(transfer Pump). No Longer Concerned With Pressure. Measure Volume For 30 Seconds, Has To Be A Minimum Of 46 Ounces And No More Than 5 Psi Pressure Drop Across Filter. Aslo No More Than 5 Inches Restriction On Suction Side. Per Tsb 14-02-03.

DCTECH- I presume you are a factory trained Tech for a dealer by your sign name? Do I just take off the line from the vp44 & measure it in a bucket? Per GeorgeW the LP runs for 20 seconds on the first fuel bump. Is the44 oz. that he mentions ok for 20 seconds? What do you think I would get when I install the FASS system? How do I measure the 5 inches on the suction side?



Murle,

What is a " Marco's CaTHER ECM "

 

[Thomas]

Does anyone know how to do this fuel flow test? I dont have a factory service manual. I plan to do this test before & after installing the FASS system.

TSB 14-002-03

 

[Sticks]

I just took my truck into the dealer because it was slow to accelerate or bogging down when cold- it clears up after 15 to 20 minutes of driving. I didnt think it was the lift pump because I had a solid 12-14 psi on my gauge- never goes below 8psi at WOT. The service rep said that i had a hard code lock for the LP & possible APPS. He said that he then did a fuel flow test & the fuel flow test failed at 30 ounces in 30 seconds & normal is 52-56 ounces/30 seconds. They wanted to change the LP & APPS to start. I have almost 80k miles on it & the service rep says that I got a lot of service out of this LP as it is. He says that they see this all the time & change a lot of LP's.

WOW!!! Look everyone, a dealership that ADMITS that they replace a lot of LP's on our trucks!



Keep this dealership, and buy the service manager and deisel tech a 12 pack! Invite them over for Thanksgiving dinner, marry his daughter, do something!

 

[Murle]

DCTECH- I presume you are a factory trained Tech for a dealer by your sign name? Do I just take off the line from the vp44 & measure it in a bucket? Per GeorgeW the LP runs for 20 seconds on the first fuel bump. Is the44 oz. that he mentions ok for 20 seconds? What do you think I would get when I install the FASS system? How do I measure the 5 inches on the suction side?



Murle,

What is a " Marco's CaTHER ECM "

Most likely the best thing you can buy to improve the performance of your truck. Go and do a search and you will find it is the longest and most talked about thread on TDR.

 

[Renoram]

Thanks everyone for the great inputs & help. I got my FASS from Brad yesterday as promised & installed it today. Took a little longer than expected though (4 hours). Had problems disconnecting the electrical connector on the LP- it was frozen in & I have a 60 gal fuel tank so room was a factor on top. I had trouble starting after I completed the job. Found out I had to bleed the system many times & loosen the filter to start the flow for priming. I had a hard time starting it but after many attempted starts & bleeding at IP she is running. It solved most of my problems but is still a bit slow to accelerate. I think I am going for my APPS next week to see if I can full clear up my problem.



One more question for those of you out there that have Fass. I have a Westach electrical gauge. I did not look for the gauge port on the FASS until I already had it mounted. I cannot find it to hook up to read my pressure. Can anyone tell me exactly where it is. I found the 2 allen screws & the 2 heater ports but nothing else that is supposed to be stamped "G". Also can i run a tee fitting near the original filter in the new hose so I dont have to run new wires all the way back to the FASS?

 

[Renoram]

I finally fixed the slow to accelerate problem. First I installed the FASS system. Then the APPS. Then the IAT sensor. all with no help. Finally I changed the MAP sensor this weekend. That did it. She now runs like a top. I can feel better aceleration than before now. I think it may be the FASS system. My fuel press is 17psi at idle & 15psi at WOT.



Thanks again for everyones help.

 

[ed9824v]

I finally fixed the slow to accelerate problem. First I installed the FASS system. Then the APPS. Then the IAT sensor. all with no help. Finally I changed the MAP sensor this weekend. That did it. She now runs like a top. I can feel better aceleration than before now. I think it may be the FASS system. My fuel press is 17psi at idle & 15psi at WOT.



Thanks again for everyones help.

what size socket if you recall did you use to remove the Map sensor. I believe it called for a 1 3/16 but could not get it to work thanks ED 98 v24