Engine/Transmission (1998.5 - 2002) lift pump test

[Jellis]

My vp44 died in nov. 2005 and the engine code I got said the ECM was not communiating with the inj. pump. $1400 later I still had concerns about my lift pump. I don't have the money for a guage, is there any way I can test my lift pump to see if it is bad?

 

[RAJohnson]

If you can borrow a Mechanical gauge from some one close , you should be able to screw it in to the OEM FF housing and check fuel pressure.

 

[DMcPherson]

bd has a low pressure led kit. its like 50$ led comes on under 5psi. cheap and effective.

 

[HeavyHauler]

Jellis - come to our Mid-Tenn chapter meeting in Dickson and we'll check it for you (free). See the TDR Home Page for details. Several of us have gauges and we'll know within minutes whether it's dead or alive. If you can't make it for some reason, get with some of the Mid-Tenn crew in your area and someone will help you out. Go under 'Local Regional Chapters and Events' and introduce yourself under the Mid-Tenn Roundtable forum.



Hope to see you there! We're expecting upwards of 100 people from Tennesee and bordering states.

 

[Bob4x4]

You don't need a gage... ... ... just measure the volume. Pull the hose off between the fuel filter and the injection pump,catch the fuel in a suitable container bump the key you should see a good flow,no air and about 50 oz in the 25 seconds. You should run the test about 3-4 times to make sure it is a reliable avg.



Bob

 

[HeavyHauler]

I'd pull the line between the lift pump and the fuel filter instead of the fuel filter and VP44. A clogged fuel filter could skew the results. This used to be how most dealers checked the lift pump. I wasn't sure how much it was supposed to flow though.

 

[Bob4x4]

I would certainly hope that no one would change an injection pump and not change the filter :-laf The test is supposed to be done POST filter :-{} If you want to get technicle you are also supposed to check for restriction also but ifd you don't have a pressure gauge it is a safe bet you won't have a vacuum gauge and the correct test set-up either :-laf :-laf :-laf



Bob

 

[Bob4x4]

I would certainly hope that no one would change an injection pump and not change the filter :-laf The test is supposed to be done POST filter :-{} If you want to get technical you are also supposed to check for restriction also but ifd you don't have a pressure gauge it is a safe bet you won't have a vacuum gauge and the correct test set-up either :-laf :-laf :-laf



Bob

 

[HeavyHauler]

Well... I dunno, but replacing a lift pump based only on a post-filter test isn't a good idea in my book (or to Dodge apparently). If you really want to get technical, you should measure both pre and post filter and then measure the pressure drop. The specs are in the service manual.



Oh, and his VP was replaced back in November, and that's plenty of time for a fuel filter to become restricted.

 

[Thomas]

Diesel Transfer Pump Diagnosis (TSB 14-002-03): http://dodgeram. info/tsb/2003/14-002-03.htm

 

[nps]

Well... I dunno, but replacing a lift pump based only on a post-filter test isn't a good idea in my book (or to Dodge apparently). If you really want to get technical, you should measure both pre and post filter and then measure the pressure drop. The specs are in the service manual.



Oh, and his VP was replaced back in November, and that's plenty of time for a fuel filter to become restricted.

Dodge does check the fuel filter - only AFTER the post-filter lift pump test fails. If the LP is good post-filter then the filter is good by default - right?

 

[Bob4x4]

Dodge does check the fuel filter - only AFTER the post-filter lift pump test fails. If the LP is good post-filter then the filter is good by default - right?

Bingo



Bob

 

[HeavyHauler]

Dodge does check the fuel filter - only AFTER the post-filter lift pump test fails. If the LP is good post-filter then the filter is good by default - right?

Well I think that's pretty obvious - my point comes from when a lift pump is replaced solely because of a low post-filter reading. I don't see what the argument is. I was trying to provide the thread originator the most accurate information I knew. Many people might not realize that a fuel filter can dramatically affect pressure readings.



There's no way that pulling the line post filter and then measuring the volume can be a 100% accurate test. If doing this with a brand new filter, then it would seem more reasonable. The first thing most dealers will ask you is if you've changed your fuel filter recently. If you haven't, that's the first thing they will do. But I would still want to pull the line pre-filter and measure the correct volume for that point. Then you will know exactly how the lift pump is performing, and you're not including other variables. Does this not seem obvious to anyone else?

 

[nps]

Well I think that's pretty obvious - my point comes from when a lift pump is replaced solely because of a low post-filter reading. I don't see what the argument is.

Nobody ever said to change a LP on a bad reading. So there is no argument, other than your statement that apparently Dodge does change LPs solely on a low post-filter reading. They don't.

There's no way that pulling the line post filter and then measuring the volume can be a 100% accurate test.

Accuracy isn't the objective of the test. Good enough volume is. If the LP can do 45 oz with the filter installed, that's good enough. If the LP can't, then Dodge says to check inlet pressure with a gauge - something the thread originator doesn't have or we wouldn't be debating this anyway.



So what the thread starter needs to do is check volume post-filter. If it is bad, then change the filter and see if it improves. If still bad, then it's LP time.

 

[Thomas]

I'd pull the line between the lift pump and the fuel filter instead of the fuel filter and VP44. ... . This used to be how most dealers checked the lift pump...

If this is true then "most dealers" were doing the test incorrectly. The ISB transfer pump test procedures in the Factory Service Manuals, used prior to TSB 14-002-03, never checked fuel volume. Also, checks of fuel pressure were to be done at both the inlet and outlet of the fuel filter (Schrader valves at inlet of fuel filter & VP44),

 

[HeavyHauler]

If this is true then "most dealers" were doing the test incorrectly. The ISB transfer pump test procedures in the Factory Service Manuals, used prior to TSB 14-002-03, never checked fuel volume. Also, checks of fuel pressure were to be done at both the inlet and outlet of the fuel filter (Schrader valves at inlet of fuel filter & VP44),

Thomas you're right about that. I've got a factory service manual as well. But when I had mine checked and replaced, they did the volume test. Apparently that's a better method to them.



If you'll read my earlier posts, you'll see that I outlined this same procedure.

 

[HeavyHauler]

So what the thread starter needs to do is check volume post-filter. If it is bad, then change the filter and see if it improves. If still bad, then it's LP time.

Good grief, I still don't see the point of this. If you want to check the lift pump, then check the lift pump! Not the fuel filter, then the fuel filter again, and then the lift pump. You're taking the long way around and probably wasting money and not to mention time in the process.



You've got the risk of wasting a perfectly good fuel filter if you do this per your instructions and it takes longer - doesn't make sense to me.



Anyway, enough of the thread hijack - jellis, just come to the meeting next Saturday and we'll get it figured out.

 

[nps]

... doesn't make sense to me.

Guess not. But he did ask for a test procedure WITHOUT a gauge.



If you have a gauge go help him out - I'm too far away (and off this thread )

 

[Jellis]

Thanks for the info, I did not mean to start a ******* match , but the info will be handy