JVDodge

I have been reading the threads on this similar topic and wanted to post to querey the experts (as we all are).

I have a 2001 Dodge 2500 with 160K miles. I have recently (5k mi ago) replaced both the lift pump and IP and installed a pressure gauge. I also have a chip that has been installed for ~ 3 years. The truck has been running excellent until a few weeks ago. I'm getting a hick-up type of missing at 1200 -1400 RPM's while cruising at ~45-55 MPH. Wondering if it could be fuel injector (have used injector cleaning addatives) or possible TPS problems?

I welcome your input............

Gene007

I have had this problem for long while. I've changed every sensor, APPs (twice), injectors, adjusted the valves, checked all grounds and had the transmission check. Also added the DTT filter. I'm probably forgetting something but I have had no luck in fixing the surge. The surge was the initial problem, then I've notice that it will idle good till it is warm, then start missing. If the truck has any load applied to it such as air conditioner kicking on or putting the truck in gear while holding the brake it will smooth out. Have not found a mechanic that can just listen to the engine and then guess what it is, All the Dodge mechanics will do is throw their hands in the air, saying I have too much after market toys added on. The computer can't tell them the problem so they are lost.
I hope you have better luck,
Gene

Edit: I also changed out the VP44 twice

Sask

Long post, sorry. A lot of people have this issue, and I'm surprised that there hasn't been some sort of solution reached yet.

I take it that both of you have a "thermal variable"? That is - the problem occurs more on warmer days, or after a long run, or after a shut-down, a short wait-time, and a restart? I'm wondering whether it has to do with fuel temperature and latent heat in the pump casing. (Not the electronics package, which seems to all be of the post-Fedex, resistant-to-thermal-cycling-breakdown kind, but the IP case itself.)

Is it possible that the cases (which are often reused on rebuilt units) are warping, and shaft washers, seals, and other hardware are allowing internal pressure leaks, etc.? Could it be a problem that becomes more noticeable with heat? As long as the temperatures of fuel used as coolant and the cases are low, the issue isn't apparent, but as the fuel heats up, or after heat-soak into the pump after shut-down, seals and diaphragms leak, washers don't quite seat, etc., because of heat-related warping.

Am I right in assuming that most VP-44 rebuilders don't have the expensive test bench necessary to scope out these problems? They just sort of eyeball things?

I had a big, irregular miss and an occasional surge at 1200-1700 rpm that I solved by replacing the ETC sensor. The engine ran perfectly for 8000 miles, but now I have a different issue - a small, ragged miss that spans the range between idle and 2800 rpm. No surges, no codes - and like others I've replaced all sensors, the lift pumps, the VP-44, injectors, filters, tested the timing box and gauges, checked for leaks and blockages, etc. My current problem is thermally-related: it happens on hot days, after long runs, or after a 10 minute to 3 hour shut-down and restart.

Dumping ice packs on and around the IP's electronics package does nothing. However, using icepacks and spraying icewater on the IP case and along the fuel line between the filter and the pump for ten minutes or so smooths out the miss. That's very suggestive. Also suggestive is this: When the engine is running well, I can replicate the characteristics of the miss at idle by dialing down the lift pump pressure to 2-3 psi - and yet I have a good fuel pressure gauge and it's registering 18-20 psi at idle (2 LP's in tandem, both tested and functioning - and the pressure gauge hooks in at the schrader valve on the VP-44 inlet).

I wonder if many of us with rebuilt VP-44's have bad cases and and/or other hardware are normally reused by rebuilders. I wouldn't know how to test for this, and I'm not at all inclined to buy another IP for fear that it's just a $1200 crap-shoot.

Frankly, I hope someone can tell me that I'm dead-wrong.

JVDodge

Yeah.......As Usual, it appears that this is not a simple fix. I assume that the VP-44 is the Injector Pump? Or is it the Vacuum Pump? Never the less, I have replaced both. Any experience with TPS (Throttle Position Sensor) wear or adjustment?

Fishing at this point!

linetrash75

I to have the same miss Gene007 has explained down to a tee. I thought replacing IP would help but nothing still there. Have you guys pulled your injectors and had them pop tested this is my next step. It doesn't seem to affect power just darned annoying. I have removed every ground cleaned both surfaces and coated with electrical joint compound still no change. I don't want to go throwing money at replacing sensors that probably are fine as some have down with no change in idle quality. Also I have been running quite a few different injector cleans at double dose no change.
thats put pur heads together and get this worked out.

Jed

JVDodge

Well guys.....I hope that someone out there has a solution. Because, it seems like all of us Dodge owners are part of a vodo cult or something. I wonder if the Chevy & Ford guys are having the same problems.

These darn Dodges are very sensitive...........

Gene007

LineTrash, I have two sets of injectors that I have been swapping out to get tested and try and solve my problems. When I put my Mach 4 injectors back in this week I found that I had an old compression ring on the bottom of one injector. Put all new ones and the idle miss is gone . The surge is still there So the idle miss was injector related, maybe this could help you. Pull and test your injectors and be sure to put new compression rings on all when installing. What gets me is there are no more seat of the pants mechanics anymore, just techs. None ever even mentioned that it might be bad compression rings. I think I've told them more about cummins than they new, Maybe hang an ole' shingle out front of my place "Mechanic". Think I could do as good.
Regards, Gene007

Sask

sigh.... In my case, I've already replaced all of the injectors and the compression rings. No change.

Just a miss that won't go away except when it's cold. Now I'm thinking maybe the fuel solenoid switch in the VP-44? But wouldn't that set a code? (ya, I know - maybe, maybe not....)

JD730

Hmm. sounds like a bunch of us have issues.
Check this thread that I started and nobody even replied on, sounds very similar to what some of you are experiencing.
https://www.dieseltruckresource.com/...d.php?t=119075

linetrash75

What about replacing crossover tubes I've heard if the injector line getts tightened to tight it will deform crossover tube. has anybody done an oil analise to see if theres any fuel in the oil? I'm convinced the problem is after VP as it missed before replacement and still does after replaced. It doesn't bother me any in the summer as A/C runs constantly which produces nice smooth idle. I cannot hear that it misses driving at all just idling.

Jed

neveragain

Yes mine bucks terribly at this rpm band!!! Always has!!! and gutless to date I have run 50 diesel engines. from farm tractors to hiway tractors and most in between. Even the JD 410??? SL's they have wonderful power for lifting rig mud, and digging 4 foot frozen clay in the winter. The Ford 3000 super dexta with the brush cutter on it cutting the Scotch Broom 13 feet high the engine doing 1800 laboured down to 600 working away at 600 rpm in first gear cutting the broom. To have that kind of power would be wonderful!!!! To have been able to have that kind of power from this 5.9 cumin or lack of power.

Itsmejoe231

I have searched hi and low for those brass washer. Where can I get a set or two?

Gene007

You can try farm equipment dealers that sells Cummins engines or find a diesel injection service where they work on injection pumps and pop test injectors.

Gene

kipo

Welcome to the club boys. Seems mine started when i did the head gasket. Rebuilt the head, .10 over marine, valve adjustement, mach 4's and 1.6's, new connecting tubes, IA sensor, mapp sensor, fluid damper, push rods, vp 44, pulled the comp, and sent to dodge for two weeks. I did find out that I had a boost leak and it made a difference in sound but it's still there. Mine however is when you rev to about 1800 rpm's. I'm going to try a new apps, and pcm (? one on firewall) soon to see if that helps. They did the cylinder drop test but the tool only revs to 1500 rpms and the miss is not present below 17-1800 rpms. I give up on it for now. Everyone please keep us posted on results.

Gene007

Kipo, My next step is to pull the head and have it checked out (valves, gasket). I have done all I can think of so far. Did your problem start after pulling your head or before? My surge has to be fuel/air related and happens while engine is not under load or while slowly backing off of throttle. The problem gets worst as I step up to bigger injectors, the surging is more pronounced. Also as time past the surge is getting worst. Thats why I was thinking maybe a valve problem.
Gene