Jump to content
  • Welcome To Mopar1973Man.Com LLC

    We are a privately owned support forum for the Dodge Ram Cummins Diesels. All information is free to read for everyone. To interact or ask questions you must have a subscription plan to enable all other features beyond reading. Please go over to the Subscription Page and pick out a plan that fits you best. At any time you wish to cancel the subscription please go back over to the Subscription Page and hit the Cancel button and your subscription will be stopped. All subscriptions are auto-renewing. 

Engine Stutter/cough on acceleration...is vp44 bad?


Recommended Posts

Yep, looks to be a stock one.  Might want to go to the auto parts store and see if you can either purchase a pressure tester kit for fuel pressure or see if you can rent one.  It'd be good to see what your fuel pressure is at with that pump.  If its low then your VP is probably toast also.  Your VP pump needs the steady flow of fuel to keep cool if your lift pump goes out the VP will still be able to pull the fuel but there won't be enough to keep it running cool and it won't be long before it dies completely.

 

Don't worry about the questions.  They aren't stupid.  I had a lot of the same questions when I got my truck too.  This place helped me a lot over the last year or two.

 

 

Edited by hdpwipmonkey
dripley beat me to it...
Link to comment
Share on other sites

Pump mught have failed completely. Main reason mOst all of us have FP gauges.

A weak or failed lift pump=a failed or weakened VP.

 

You could put some 2 stroke oil in the fuel and see if that. Wally world is fine. TCW3 ashless is what you are looking for. 

Edited by dripley
Link to comment
Share on other sites

44 minutes ago, Zekeworst said:

Also: I apologize for all of you who may think I’m asking “stupid” questions. I’ve never owned a diesel before and I’m just trying to make sure I can (hopefully) pass this truck on to my future child(ren). 
 

Yup. It’s stock. I see a mopar sticker on it. 

image.jpg

So... From what I’m gathering, I can either: 
A. Replace the lift and in tank pump and hope it fixes the problem

B. Replace the VP pump (which will most likely fix the problem 
C. Replace all of those components and KNOW it will fix the problem. Damn owning a diesel is an expensive hobby... ?
 

I also just noticed that there’s a slight crimp on the inlet side of that lift pump. That could be why it’s doing all of this. I’ll see if I can uncrimp it. 

A. You dont have both most likley. The in tank pump was a Dodge solution to the block mounted pump. They both suck.

B. Most likely. Test the existing lift pump pressure first.

C. Most any 20 year old vehicle can be expensive at times. Haevy duty vehicles can be pricier. 

Link to comment
Share on other sites

24 minutes ago, Zekeworst said:

Also, I was just curious if the pump would prime so I tried bumping it to see if I could hear it prime and It didn’t.

 

That is a good test.  When you turn the key into the "run" position, the lift pump will run for about 1/2 second.  When you bump the starter, the lift pump will run for about 20 seconds.  Make sure the key is in the "off" position (key can be removed position) before you start the test or you may get erroneous results. 

 

If you are not hearing the lift pump run, the, check the condition of the fuse.  If it is blown, the pump may be faulty and drawing an excessive amount current.

 

If you are going to keep this truck, and it sounds like you are, then you should invest in a factory service repair manual for your year and model of truck. This manual will show the locations of all electrical grounds for inspection.  Or, you could become a member of this site and use the site's available resources, such as wiring diagrams.

 

- John

Link to comment
Share on other sites

Just checked the fuse. It’s good. Now my brake lights won’t work. I’ve checked the fuse on it, it’s good, and I’ve got power going all the way back to the socket. Now to test the switch... 

Edited by Zekeworst
Link to comment
Share on other sites

49 minutes ago, Zekeworst said:

Just checked the fuse. It’s good. Now my brake lights won’t work. I’ve checked the fuse on it, it’s good, and I’ve got power going all the way back to the socket. Now to test the switch... 

Here is one that takes some getting used to. Most of the electrical system is negatively switched. You can have power to the socket and it still not work because the ground is not complete. You have probe the + and - in the socket.  I would have to defer to those more knowlegable to explain that though.

Help guys, a bit out of my league on this.

 

Edited by dripley
Link to comment
Share on other sites

Switch only has constant power (white wire) and the other connection on the four prong connector for the brake lights does not trip my test light. Turn signal and constant power work but the other wire doesn’t trip the test light. I’m at a loss. At this point it’s this kind of little sh!t that’s making me want to get rid of it. What bothers me the most is the fact that yesterday they were working just fine (and they have worked for the past 7 months since I got it) and now they just don’t work. 

Edited by Zekeworst
Link to comment
Share on other sites

  • 3 weeks later...

So... Update on my truck. I haven’t been able to get anywhere in terms of checking fuel pressure. I recently moved (my old roommate upped the rent on me) and haven’t had the finances to do anything more with it. BUT... I was able to check all of the grounds (finally) and just recently (a couple days ago)I noticed that the lift pump FINALLY decided it wanted to start working again. By happenstance, when I turn the key to the run position, I heard it prime for about 30-45 seconds. If I bump the engine, it primes again for roughly that same amount of time. The stutter is still there. Yesterday when I drove it, it didn’t stutter at all. There was consistent power from both a dead and rolling stop. 

Link to comment
Share on other sites

5 hours ago, Zekeworst said:

I heard it prime for about 30-45 seconds. If I bump the engine, it primes again for roughly that same amount of time.

Should only be a second on key on and 30 or whatever seconds on the key bump. Wonder if you don't have a timed relay in fuel pump harness. You could just check the ECM plug for voltage in both situations.

Link to comment
Share on other sites

2 hours ago, Dieselfuture said:

Should only be a second on key on and 30 or whatever seconds on the key bump. Wonder if you don't have a timed relay in fuel pump harness. You could just check the ECM plug for voltage in both situations.

Yes, you’re correct. It was late when I posted that and I was tired. I was falling asleep when I was typing it. It only runs for a short time when the key is on and after bumping it, it runs for awhile. 

Link to comment
Share on other sites

  • Staff
On 5/14/2016 at 6:51 PM, dripley said:

Volt meter is low also. That could be part of the problem. How did you check the codes? Fuel filter good?

You got bad ground or bad positive side somewhere. If you watch even the oil pressure gauge coincides with the engine miss fire. Also possible low tank level gauge from a bad connection. Film shakes around a bit to tell much on the fuel gauge tho.

Link to comment
Share on other sites

  • 4 weeks later...

I’ve decided to replace the VP44. She needs it badly. One other side tangent. I now have what seems to be low compression. The truck idles really rough (enough to shake the truck back and forth). There’s white smoke coming out from behind the ECM (on the side of the block) where the fuel filter is (I haven’t been able to isolate the leak yet). I’m wondering what kind of seal(s) could be down in that area and how easily they can be replaced. 

Link to comment
Share on other sites

The factory lift pump was mounted just to the rear of the filter canister. If your pump has been removed/relocated there should be a metal plate in its place sealing a hole in the block. It could have come loose and be venting crank case gases.

Link to comment
Share on other sites

Dug back in your and see you still have the factory lift pump. The mounting plate blocks the same hole and could leaking. Also the tappet cover, same as @Haggarmentions just a different name, could be the culprit too. Even if its not leaking change it while the VP is out. Much easier that way.

Link to comment
Share on other sites

×
×
  • Create New...