Engine/Transmission (1998.5 - 2002) Lift pump fuel supply woes

[DavidC]

Thanks for the tips guys. I'm flying back home today and will research the "vent" possibility first. Then probably look into a plugged pre-strainer. Not looking forward to another diesel bath.



I'll post back.



Steve

Find anything?.



Dave

 

[CORed]

Unfortunately no, but the problem went away too.



I replaced the pre-strainer with another one and cut the first one open. It was clean inside. So it was not the problem. The wiring looked good and I didn't change that. I vented the tank when it was acting funny by taking the cap off and no difference there either. The only other thing I did was when I replaced the pre-strainer, I blew 20lb of air back up the hose and into the tank for a few seconds. It bubbled a lot inside the tank, but that was it. After doing all this, it still didn't act like it should.



About a day later, I washed the truck good including underneath and the pump and honestly, it was shortly after that when the pressure stayed high as desired. I doubt it was the cleaning, but nothing else really changed. I now have 15+ lbs almost all the time and it barely dropped a 1/2 lb going up hills. It still occasionally acts a BIT funny like dropping down to 11lb sometimes, but 98% of the time now it is rock steady. BTW, I had asked Doug to pre-set the regulator for around 16, not the 18-20 so 15+ is exactly what I expect.



So I'm going to keep an eye on it, but for now, I'm pretty happy w/ it. Just wish I knew what changed.



I do love the fact that it is quiet! Man, that is nice.

 

[DavidC]

Thanks for the update. Kind of sorry you did not find something conclusive though. Those kind of things tend to come back and haunt you at the most inopertune time.



Dave

 

[Gary - K7GLD]

For what it's worth, and only related to a couple of posts in this thread concerning cavitation and erratic PSI - I have had similar symptoms with my OEM LP and the added Carter pusher down on the frame. Absolutely NOTHING wrong with either pump, just apparent variations in characteristics of the fuel, plus the PS and 2 stroke oil I add to my fuel for VP-44 lubrication.



ANYWAY, the permanent (so far!) fix was to move the OEM LP down to the frame rail near to where the pusher pump is - I've had no further cavitation problems, and still running all the original LP and pusher pump since new...

 

[KMLyon]

VP44 done?

Guys;

Followed this thread and need some confirmation. Have had erratic LP pressure for awhile so changed pump with Vulcan relocation kit and new Carter pump (cummins part). Just back from Ill where truck let me stranded. LP press was fine when we left, but progressively got worse (just like before LP pump change) with 15 psi idle degrading to 2-3 psi on hills. Turned around and headed home but stoppped for fuel and truck had long crank and then died for keeps a mile later.



Got it to restart cold this morning, but wouldn't accept any load at all and then started to smoke heavily.



Truck is a bone stock 99 2500, with only mods a gauge pack and new LP with Vulcan kit. I've also had the dreaded "whoosing sounds" when refueling for the past few years after heavy , hot summer towing.



My conclusion is a failed VP44 pump? Any advice/comments would be appreciated.

 

[Mad Bomber]

Cut screen long time ago in the pick-up and the problems went away. BTW it was suggested by Dan the FASS man.

 

[DavidC]

Guys;

Followed this thread and need some confirmation. Have had erratic LP pressure for awhile so changed pump with Vulcan relocation kit and new Carter pump (cummins part). Just back from Ill where truck let me stranded. LP press was fine when we left, but progressively got worse (just like before LP pump change) with 15 psi idle degrading to 2-3 psi on hills. Turned around and headed home but stoppped for fuel and truck had long crank and then died for keeps a mile later.



Got it to restart cold this morning, but wouldn't accept any load at all and then started to smoke heavily.



Truck is a bone stock 99 2500, with only mods a gauge pack and new LP with Vulcan kit. I've also had the dreaded "whoosing sounds" when refueling for the past few years after heavy , hot summer towing.



My conclusion is a failed VP44 pump? Any advice/comments would be appreciated.

Is this pressure pre or post filter?. If post I would be looking at the filter. If pre it could be the LP, strainer in tank, screen in pump etc. I would get some 5/16 hose and 5 gallons of diesel. Hook the hose to the lift pump and the other end in the jug. If pressure comes up it is most likely at the tank. If it remains low I would change the filter before condemning the lift pump. Either way I do not think it is the VP44 yet.



Dave

 

[DavidC]

Just caught the whooshing part. Tank not venting?. I would try the loose fuel cap and see if that helps before looking to see why the tank vent is not working. I would not drive around with a loose cap and a full tank of fuel tho.



Dave

 

[DMannon]

What DavidC said... while low pressure isn't good for the VP, it doesn't cause low pressure. Check your codes. The low pressure can be caused by plugged pickup screen, plugged fuel filter, bad LP, air getting in the lines... that's a partial list. The whoosh definitely sounds like a tank venting problem.



Try bumping the starter and listen to the Carter run. Does it make any clicking sounds as it builds pressure? That's cavitation, usually caused by lack of flow, think obstruction. Try disconnecting the line at the fuel filter and put it in a bucket. Bump the starter. You should get about 1/2 gallon in 20 seconds. Any less, the LP isn't pumping. Bubbles or foamy, you're getting air in the lines.



Let us know what you find.

 

[KMLyon]

Thanks!..... home on flatbed tonight. Local dealer in Ill (where it stranded me) read the generic #1693 code. He claimed it was in both PCM & ECM but that seems strange to me. Anyway, it's pretty much a no-start now, but when it does, it smokes heavily and has little or no power. I had just replaced the LP with a new Carter and Vulcan relocation kit and it ran fine for the first 300 miles. Then after the firstfuel stop with new very low sulphur fuel, the LP press dropped low and would only hold 2-3 psi on hills.



How are the ECM codes read? Does the DRB scan tool read both, or didn't the local mech know enough?



Thanks for the feedback.

 

[Bob4x4]

on the 24v trucks you have the pcm and the ecm both listed in the drb menu under engine... ... ... you must make a choice to view one or the other. One more time,I will say 1693 NEVER shows up by itself. Who ever was checking either didn't know what he was doing or want you to see the real codes.



Bob

 

[mhenon]

Then after the firstfuel stop with new very low sulphur fuel, the LP press dropped low and would only hold 2-3 psi on hills.

Have you changed the fuel filter yet?

Mike

 

[DMannon]

Thanks!... Local dealer in Ill (where it stranded me) read the generic #1693 code. He claimed it was in both PCM & ECM but that seems strange to me.

This forum is full of horror stories of Dodge dealers not knowing squat about diesels. Also, 1693 is simpy a code saying the ECM and PCM are not communicating, and yes, it normally comes with something else.



My guess is you're having a problem related to your recent Big Line and relocation install. Check some simple stuff, filter, is there fuel in the tank, tank venting, all the connections you made in the relocation. Then check to see if you're getting air in the line somewhere, and give the tank a slight blast of compressed air to see if the pickup is clogged.



When you tried to start the last time, did you try bleeding the injectors? If so, was there fuel coming out of each before you tightened them up?

 

[KMLyon]

Thanks for all the help guys. I'll bring home a DRB from work (DCX) and figure out ECM code. Had a marginal LP pump for probably 2-3 years before I put a gauge on. Ignornace is bliss. I'll check all the obvious stuff first (filters/strainers/bad fuel)... . maybe the VP44 is not dead yet. Also somewhat ironic the trouble ocurred with my first 2 tanks of low sulphur fuel. As you've probably all heard, lubricity of this new fuel is somewhat suspect on older HP pumps.



Many thanks for all the posts. Made me feel sorry for consumers that bring in their trucks expecting some diesel expertise. I had a bad feeling when I talked to them on the phone (and confirmed when I went back to get the truck) which is why I sent a flatbed over to bring the dead dog home. They meant well, but didnt know squat.



At least there's the TDR forums to help keep our Cummins rolling.

 

[Bob4x4]

This forum is full of horror stories of Dodge dealers not knowing squat about diesels. Also, 1693 is simpy a code saying the ECM and PCM are not communicating, and yes, it normally comes with something else.



QUOTE]

No 1693 is not a communication failure code!!!!

It simply means you are looking in the wrong (engine module) for the code that has been set



Bob

 

[DMannon]

My bad...

P1693 (M) DTC Detected in Companion Module A fault has been generated in the companion engine

control module.



P1693 (M) DTC Detected in PCM/ECM or DTC

Detected in ECM

A 9Companion DTC9 was set in both the ECM and PCM.

 

[SMacLeod]

Vulcan Relocation Pump

What I Need To Know Is The Vulcan Kit, Going To Solve The Lift Pump Failure Issue, This Will Be My 2nd Lift Pump, This One Lasted 4 Months. I Don't Want To Spend The Money If It Does Not Work. Has Anyone Had Any Exp. With Vulcan Kit What Is The Min. Fuel Pressure At Idle And Wide Open? Any Assistance Would Be Appreciated.

 

[KMLyon]

Vulcan Kit

I used Vulcan relocation kit, but wasn't cure after all. My issue turned out to be a badly plugged filter (well duh). Dropped tank to put in MOPAR recommended in-tank pump module and also found partly kinked supply line and defective vent valve.



So, final story is that original lift pump was fine. When I replaced it, I still had the same pressure drop climbing grades (down to 0-2 psi). Barely held 6-8 psi on the level. Now with new gear in place, I have steady 10-12 psi (measured on filter clean side). Bottom line, do not under any circumstances drive truck with pressure under 2-4 psi. Anything under 10 psi should set off alarm bells to find real cause. My filter had been clean for years and in two fills, turned to a nasty, particle-laden black mess.



current lift pump design is not great as vane style pumps are not very good at pulling fuel... ... ..... especially over a 6-8ft line. In-tank module is pricey but pushes fuel to HP pump rather than drawing fuel.



Had I put a pressure gauge in sooner would have saved myself the price of a rebuilt VP44. There is a ECM code which warns of low supply side pressure and it's supposed to set a MIL, but in my '99 truck it didn't set the light. Bad news for consumers as it doesn't give any warning until the VP44 is damaged.



Hope this helps... ... ... ... ... .....

 

[jhoughton]

Mine was getting a small amount of air at the connection at the top of the tank. Started out with slight fuel pressure fluctuations and could hear the relocated pump sound change with the pressure changes. Installed a Draw Straw and the problem has been gone now for 500+ miles. Same pump getting 12-13 idle and 11 WOT. The screen was clean and the pickup was un-obstructed. Filter was also clean when replaced.