Lift and injector pumps issue

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May 13, 2019
My name is Donald Miller and I am Scottish (we are the Brits who wear skirts and are from the bit above England and accross the sea from Ireland.)
We own a 2002 National RV Trades LTC 7374 37' 350 bhp Diesel pusher. which we bought in 2018. Having parked it up in Cocoa last year while we went home for Christmas. We returned in March and have been travelling round Florida and now in Cartersville Georgia staying at Lake Allatoona.

We have a problem with the lift and injector pumps of our coach in that they have activated a warning light on the dash 'Check Engine'.

An RV shop 'Open Roads RV' in White GA has diagnosed that we need to replace the lift and Injector pumps at a cost of $7000.
Other RV shops and a Truck repair shop who know my RV, although have not seen it since the problem arose say that it is excessive to replace both and that the lift pump is all that requires replacing at this stage at a cost of less than $1000.

Have any of you experienced this with this age of Cummings diesel. What is your story
Hi Donald and welcome from an ex-pat Taff. Jackie, one of our forum staffers, lives north of the border.

I must admit to not having had direct experience with your issue, but in my ignorance $7,000 seems a heck of a lot of money. I'll let one of our gear heads comment. Meanwhile, I'm moving your message and changing the subject line to try to attract the right folks to the discussion.
I would take it to a heavy duty truck repair shop that services Cummins, never to an RV dealer.
An injector pump is a very expensive component and hard to get at to repalce, so the $7000 price tag isn't out of line IF it really needs replacement.

Without further info as to the nature of the problem, I cannot guess if an injector pump is needed. There should be a diagnostic code associated with the Check light that  gives more detailed info.  At this junction I side with those other s shops - don't do the injector pump without further proof.

A fairly common problem is a clogged intake screen on the lift pump, reducing fuel flow to the injector pump. That acts just like a bad injector pump, i.e. it can't build sufficient fuel pressure under load. The clog comes from dirty fuel or from a type of algae that grows in diesel fuel tanks when moisture accumulates there during storage.  Algae in the fuel tank is a not an uncommon problem in diesel engines in the humid Southeast US.  Yachts and motorhomes that tend to sit around unused are more prone to it than cars and in regular use.

I agree with Gary.  The problem with electronic diagnostics is that they try to replace common sense with too much information. 
The coach sat for a while and now has issues.  This is very common for diesels because things grow in the water/fuel interface inside the fuel tanks.  Before you spend any money on other things, change out first the water separator before the lift pump and next the final filter before the injection pump.  These filters are very good ($$) and they should protect the injection pump ($$$$$) from damage.  If the filters clog up again, find someplace that can "strip" the fuel tank(s).  That means get the fuel out of the bottom of the tank(s).  It is very difficult to differentiate between a failed lift pump and a clogged filter as the results are the same.

I'm a ships engine and have been baby sitting diesel engines for decades. 

Matt C
The likelyhood of BOTH failures at the same time is nil,, don't buy it. That reeks of poor guess work instead of accurate diagnostics.>>>Dan
I'm guessing you have a 2002 Cummins with the VP44 injector pump. If you do,,,,,,,,,They were not a great pump and have about 100-120k life in a pick-up truck, "if" the lift pump, filters were maintained and clean fuel used. Motor homes may also have a in tank pump, IDK about that part. Here's the low down on the VP44 pump.  The lift pump losing pressure, slowly failing, this is a common reason the VP44 injector pump fails early. If the VP44 is starved for fuel it heats up and cooks the electronics that are part of the pump. The VP depends on 8-10 psi fuel supply to keep it properly cooled. This is why it's important to be on top the maintenance with this generation Cummins motors. A rebuilt from a known reputable shop is around 1k, you really want a good rebuilder for this pump. Lifts pumps around 100-150.00 There is a flow chart to follow diagnosing the VP44 put out by Dodge. I agree with other about taking it to another shop, Even if you all your parts were around 1500.00,,,5500.00 for labor sounds crazy I just went thru all this with my sons 2002 Cummins. We found the lift pump was down to 5-6psi, and suspected the VP44 was cooked,  but after going thru the flow chart it ended up being the ECM, still 1k. I know my experience is not with a motorhome, but may help you to get a little more info out of a shop,,gregg
Boater: Are those DIY prices or repair shop prices?  Shops typically have a substantial mark-up on parts and shop labor rates run $120-$150 these days. Especially RV shops.  An ISC is typically installed with a rear radiator and not very accessible for repairs (mor elabor hours).

I'm not familiar with the 2002 Cummins ISC or the VP44, but a High Pressure injector pump for an ISL runs about $3000 if purchased direct and repair shops often mark that up 30% or more.
I had an experience with my lift pump that might help.

When I was driving from Quartzsite to the flooded hospital in south Carolina I had a problem with my lift pump on a Cummins ISC.

I ordered a replacement from a cummins dealership and then called a mobile mechanic to replace the pump.

To access the pump he had to raise the bed and then remove a access panel in the floor.  The pump is on the side of the engine.  The mechanic discovered that the bolts that held the pump to the engine block were loose.  After tightening the bolts the pump worked perfectly.  It turned out that the Cummins dealer had sent the wrong pump anyway so they refunded my money after I returned the pump.

I hope that you might be so lucky and I would suggest that you check the tightness of the bolts on your lift pump.
Gary, I don't know what motor he has, only stated 350hp, since its a motorhome may not be the same I was talking about anyways, that's why I said if he has that combination. I feel for the guy, these diesels are so expensive to repair and getting so the DIY'er can't any more. If it is the wrong application, my apologies for any confusion, but the info is still good for others that may have those lousy pumps and will be meticulous with their maintenance  schedule,,,gregg
Rvscot56 said:
We own a 2002 National RV Trades LTC 7374 37' 350 bhp Diesel pusher.

We have a problem with the lift and injector pumps of our coach in that they have activated a warning light on the dash 'Check Engine'.

An RV shop 'Open Roads RV' in White GA has diagnosed that we need to replace the lift and Injector pumps at a cost of $7000.

Yes, that sounds about right. Our 2001 Newmar has a Cummins 350 ISC which uses the CAPS fuel injection system which is problematic to say the least.

Here's a long IRV2 thread about the problem:
I used to choose between the first one and a different build and ... didn't decide eventually :D Now that's an issue for me again.

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