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

[Fizzle]

Hello all,

 

I have a 2001 24valve Dodge ram 2500 automatic.  Wonder if my vp44 is bad.  Today when driving,  on acceleration I got a really bad stutter/cough in the engine.  I double checked the voltage on the timbo apps and it is in spec and no dead spots. On the raptor pure flow the fuel pressure is 15psi at idle and around 12psi when accelerating. I have changed the alternator, it's in spec, I even disconnected fuse and harness to isolate if it could be that and it didn't go away. On low pressure side of vp44 primed to make sure no air on that side.  No error codes and at my wits end what to do next.  attaching a video if that helps.

 

any thoughts?

 

IMG_7611.m4v

[Dieselfuture]

double check codes with a good reader, how old injectors, 12psi is a bit low but don't think it would do that, noticed your oil pressure is low could be a bad oil sending unit that is cutting 5 volts to your map sensor, just happened to me. 

[dripley]

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

[Cumminz]

Wow. I haven't seen that before. Does it happen at any rpm? random times? codes like previously mentioned? What all do you have done to the truck?

[Hawkez]

I would suspect bad fuel.  How is your fuel filter?  What type of air filter do you have?  How does it look?  Are you saying that when it is stuttering like that your FP is between 12 and 15 PSI?  What mods are add ons have you done to the truck?

[Fizzle]

Fuel Filter is new.  No mods done to the truck...all stock, except fuel lift pump and timbo apps.   Air filter looks new.

 

Volt meter was low since this test drive was with the alternator disconnected.  Never thought of the low oil pressure sensor, probably needs to replaced as well.  My local mechanic hooked up their reader to read codes.  Happens at random rpm's and throttle position.

 

Yes....the fuel pressure is between 12-15psi when it does this.

 

I tested the Fuel overflow  check valve on the vp44 and it was way out of spec.  Opened up under 10psi, like 7psi.  I will replace that and report back.

 

thanks for all the feedback

Edited May 15, 2016 by Fizzle

[Hawkez]

Do you see this at idle as well?  How many miles are on the truck?  Are they the original injectors?

I wonder if you could be sucking air from a bad connection.  Do you ever have signs of leaking connectors or a cracked line?

[Hawkez]

Just another thought...

 

How much fuel is in the truck?  Does this only happen as the fuel gets lower?

[Fizzle]

It has a half a tank of diesel. It does not happen at idle. When in park I can rev up to 2,500 rpm with no symptoms, only happens when driving.  It hasn't happened before, just started happening and parked the truck until I figure out what is wrong. 

Not sure how old injectors are just bought the truck 208,000 miles. No signs of leaking injector or cracked lines. 

[Hawkez]

I'm not sure what could be causing this.  I wouldn't throw a VP44 at it until I checked a few more things.  I would thing that you would most likely have a code thrown if your IP was on its way out....but maybe not.  You could have your injectors pop tested.  If they are original it may not be a bad idea to assess their health.  I would changed out the fuel filter, dumb the canister in a glass jar to get a look at it.  I know you said it is new, but maybe you got a bad tank of fuel on you last fill up.  I would also throw an air filter at it and make sure that nothing is restricting air flow.  What gauge are  you using to measure fuel pressure?

[Fizzle]

3 hours ago, Hawkez said:

I'm not sure what could be causing this.  I wouldn't throw a VP44 at it until I checked a few more things.  I would thing that you would most likely have a code thrown if your IP was on its way out....but maybe not.  You could have your injectors pop tested.  If they are original it may not be a bad idea to assess their health.  I would changed out the fuel filter, dumb the canister in a glass jar to get a look at it.  I know you said it is new, but maybe you got a bad tank of fuel on you last fill up.  I would also throw an air filter at it and make sure that nothing is restricting air flow.  What gauge are  you using to measure fuel pressure?

 

I am with you on checking a few more things.  Having the injectors pop tested sounds like a good plan.  I have an electronic fuel pressure gauge on the lift pump.  I hooked up a mechanical gauge and drove around with it, it had the same readings as the gauge hooked up to lift pump. I measured at the inlet to vp44.

 

I read some other threads that had similar symptoms.  The cures were as follows in no particular order: fuel additive to clean injectors, replacing cam sensor, replacing map sensor, and fixing an air leak in fuel line.  I'll have time this weekend to work on it.  I'll do one thing at a time to try and isolate the problem.

Edited May 18, 2016 by Fizzle

[Fizzle]

On May 16, 2016 at 11:52 AM, Hawkez said:

Do you see this at idle as well?  How many miles are on the truck?  Are they the original injectors?

I wonder if you could be sucking air from a bad connection.  Do you ever have signs of leaking connectors or a cracked line?

 

guess what i noticed tonight. Is this what you meant signs of leaking connector? Looks like fuel on #5 and #6 

Edited May 19, 2016 by Fizzle

[Hawkez]

That is something to look at.  Were the nuts very loose?

[Fizzle]

 

On May 18, 2016 at 7:46 AM, Hawkez said:

I'm not sure what could be causing this.  I wouldn't throw a VP44 at it until I checked a few more things.  I would thing that you would most likely have a code thrown if your IP was on its way out....but maybe not.  You could have your injectors pop tested.  If they are original it may not be a bad idea to assess their health.  I would changed out the fuel filter, dumb the canister in a glass jar to get a look at it.  I know you said it is new, but maybe you got a bad tank of fuel on you last fill up.  I would also throw an air filter at it and make sure that nothing is restricting air flow.  What gauge are  you using to measure fuel pressure?

 

Ok.  Face in hands shaking head...embarrassment! haha   *****Problem Solved*****   Loose positive cable (can't believe I over looked that one)  and Loose connector into vp44.  Left my truck at Rincon Truck Center while I was on vacation and they had it isolated in about an hour.  Lesson learned!

[dripley]

Good to here you got it going no matter what the cause. I have had my fair share of   moments. 

[Hawkez]

Good to hear you figured it out.  It is funny how the simplest of problems are overlooked.  I've been there too.

[beanflicker424]

Hi everyone im pretty new to the whole forum thing as you can tell. I have been having some issues with my truck recently and cant seem to figure it out so that is what led me here as i know mopar1973man is a very reputable person throughout the forum community. I have a 1999 2500 24 valve automatic with the dreaded VP44. The truck is stock other than a five inch straight pipe. When I purchased the truck the man told me that the IP had been replaced before an gave me that receipt which says it was done around 150,xxx.  Earlier I went out and started my truck let it warm up for about ten to twelve minutes an went on my way might i add it is around 48 to 50 degrees here where i am. Well after i pulled out onto the road i was going up a small incline and the truck stuttered like it was missing then stopped for a moment then did it again all in the span of about ten seconds. Immediately after the check engine light came on once i got to where i was going i left the truck running then drove straight to my local auto zone an the truck ran just fine at idle and under acceleration (never got in it to much) the whole way there. When the man came out to plug in the scan tool he cut the truck off plugged it in and turned the ignition on and could not get a code so he had me start the truck an he tried again still no code so im left scratching my head. The truck hasn`t done this that i can recall even in just the few times i have went out jumping in and firing it up an taking off without letting the truck warm up for more than a minute around these same temperatures so im a bit worried with check engine light coming on that my IP is failing. Any help, informatin, or advice would be greatly appreciated

Edited October 31, 2016 by beanflicker424

[dripley]

Welcome to the forum. The VP 44 is not something to be dreaded. Mine has 170k on it with no signs of letting go. A few other members have more on theirs than I do on mine. You just need to learn how to take care of it.Not sure what your issue is but with out any codes your VP is probably OK. You would be better of starting your own thread on this to be sure it does not get mixed up with this one. Could just be a hiccup and nothing to worry about. Again welcome.

[Zekeworst]

99 Dodge Ram 2500 5.9L 24V Cummins: No rough idle, no engine light or codes, app sensor voltage (lowest @ 160.4V, highest @ 160.8V) TPS replaced three weeks ago. No rough start. When under load, throttle is jumping all over the place. There is a loss of power when flooring it and it seems to sputter for the first 15-30 minutes after startup and at speeds starting at 30 mph and lasting through 65 mph, then seems to subside once out of that range. Before TPS was replaced, I was blowing lots of white smoke (I figured I had too much oil, so oil was changed).  When the TPS was replaced, this issue stopped for several weeks until last week when I got fuel at a neighborhood Walmart. Ever since then, it’s been doing it. It doesn’t ALWAYS happen though. It’s just sometimes. It doesn’t seem to be as problematic when it’s warm outside. Any ideas? 

Photo was taken after a short (5 minute) test drive with engine warmed up. 

[dripley]

Something really wacky with the apps volts. Dont know how you could have 160.8 volts on a 12v system. Hownare you checking for codes?