Cutting Out Under Hard Acceleration/Above 68 MPH+ 2500 4x4 47re

[Dieselfuture]

I had similar problem, thought it was vp, between changing injectors, cleaning up wiring, rebuilding alternator (can just replace with a good unit) my surging went away and later I did the WT mod and it runs even better now. 

[Mopar1973Man]

I hate to guess at parts and blow good money on part that might not be it. Im leaning towards the VP44.

[MarkG]

3 hours ago, Dieselfuture said:

I had similar problem, thought it was vp, between changing injectors, cleaning up wiring, rebuilding alternator (can just replace with a good unit) my surging went away and later I did the WT mod and it runs even better now. 

 

Lucky you!!!  Mine is more than a surge.  It's pretty violent.  My alternator is the original unit and I thought maybe it was the issue BUT I have a TC lockup switch and this issue is still present with the switch engaged and torque converter locked up. 

2 hours ago, Mopar1973Man said:

I hate to guess at parts and blow good money on part that might not be it. Im leaning towards the VP44.

 

After months of researching, cleaning stuff up, rewiring the ground system and everything else considered I think it's the VP44 too.  I just pulled the connectors off the pump and ECM only to find that I need to fabricate a smaller probe to get into the contacts on the ECM side.  ugh...anyway the wires are all in excellent visible condition.  The plug on the ECM had never been removed, I cut the VOID sticker.  Crap, now they'll I've been messin around in there  hahah  I'd be shocked to find out the wire harness fails the tests but will report back once I get my little pin probe worked out.

[dripley]

I had some similar issues as @Dieselfuture had. Had a problem with the 5v signal reference and AC noise border line high. Did WT's ground mod, new battery cables and clean everything up real good. I have trouble free for the most part for the past years. No more electrical gremlins. Maybe I better knock DF's wooden head. 

[wil440]

In your first post you describe the problem as a shudder or very quick cutout, my truck did the same thing maybe a year ago, just felt like it was off for a really short time and repeated say every second or so until I backed off, if I drove really steady it wouldn't happen but the more the go pedal was pressed the worse it got OR the bigger the grade/load.

On my truck it was fuel pressure, It had a Fass direct replacement bolted to the block.

I removed the pump and went mechanical..... problem gone, never hickups at all now.

I see you have 14psi fuel pressure, is this on a mechanical gauge or electric, if electric I'd be testing that with a mechanical one as a reference.

One another note .... how old is the fuel filter ??

[Mopar1973Man]

4 hours ago, wil440 said:

I see you have 14psi fuel pressure, is this on a mechanical gauge or electric, if electric I'd be testing that with a mechanical one as a reference.

 

This why I created the sensor bracket I did so testing is super easy. 

 

I just unscrew the sensor add a tee hook up my mechanical gauge and drive. I can do the same thing with the boost sensor too. No digging at the block and fighting to change sensor for test gauge. Losing prime etc. 

[wil440]

3 hours ago, Mopar1973Man said:

 

This why I created the sensor bracket I did so testing is super easy. 

 

I just unscrew the sensor add a tee hook up my mechanical gauge and drive. I can do the same thing with the boost sensor too. No digging at the block and fighting to change sensor for test gauge. Losing prime etc. 

proper old fashioned mechanical gauge here, the less electrical stuff on my truck the better

[MarkG]

8 hours ago, wil440 said:

In your first post you describe the problem as a shudder or very quick cutout, my truck did the same thing maybe a year ago, just felt like it was off for a really short time and repeated say every second or so until I backed off, if I drove really steady it wouldn't happen but the more the go pedal was pressed the worse it got OR the bigger the grade/load.

On my truck it was fuel pressure, It had a Fass direct replacement bolted to the block.

I removed the pump and went mechanical..... problem gone, never hickups at all now.

I see you have 14psi fuel pressure, is this on a mechanical gauge or electric, if electric I'd be testing that with a mechanical one as a reference.

One another note .... how old is the fuel filter ??

 

The fuel pressure gauge is electric and I don;'t have any reason to thiunk is't not accurate.  When it's cold I can see the pressure fluctuate a tad bit.  It operates like it should upon start up.  The FASS Titanium pump is purring away like a kitten.  But who knows!?  I don't have a manual gauge around Fuel filters are only a couple months old. I changed them when I did W-T's ground mod actually. 

 

I was out and about again yesterday and really tried to hear what was going on when it's having the problem.  Really think it's a fuel delivery issue but absolutely don't want to rule anything electrical out.  Have not made my little pin probe adapter for the multi meter so the wiring VP-ECM is still not tested.  It sounds like the engine RPMs actually go up when the truck is cutting out. It's so counter intuitive but it really sounds like that's what's going on.  This is a truck I plan on keeping forever.  I don't like new computerized luxury trucks and plan on keep this old girl until I can't drive anymore.  She's worth the struggle!!!

4 hours ago, Mopar1973Man said:

 

This why I created the sensor bracket I did so testing is super easy. 

 

I just unscrew the sensor add a tee hook up my mechanical gauge and drive. I can do the same thing with the boost sensor too. No digging at the block and fighting to change sensor for test gauge. Losing prime etc. 

 

Nice!  What have you found when you test the mechanical VS electric?  Lots of electric gauge failures????  Is this something we should all consider in your opinion?  I've built a lot of cars over the years and have never seen a single gauge failure in any of them. 

19 hours ago, dripley said:

I had some similar issues as @Dieselfuture had. Had a problem with the 5v signal reference and AC noise border line high. Did WT's ground mod, new battery cables and clean everything up real good. I have trouble free for the most part for the past years. No more electrical gremlins. Maybe I better knock DF's wooden head. 

 

My battery cables are original but look like they are in great shape still.  Truck just turned 150,000 yesterday.  How hard was your stumbling cut out?  Minor?  Major?  I don't want to rule anything out.  Thank you all so much. 

[Mopar1973Man]

42 minutes ago, MarkG said:

Nice!  What have you found when you test the mechanical VS electric?  Lots of electric gauge failures???? 

 

Not if you install my method you'll never have an issue. The biggest thing NEVER direct plumb a fuel pressure gauge. At the tap point you need both the needle valve (safety) and the sintered metal snubber. Then you need at least a minimum of 5 feet of 1/8" air brake line. If you can use more that is great longer the better. The distance from the VP44 tap point has to be far to fade out remaining pulses. I've never had a fuel pressure sensor failure yet. 

 

Mechanical are the same you need the same snubber and valve but you have the distance into the cab. 

42 minutes ago, MarkG said:

I've built a lot of cars over the years and have never seen a single gauge failure in any of them. 

All you got to do to kill a fuel pressure sensor is install it directly at the VP44. The pulses will beat it to death in mere few months and be leaking by then. 

 

42 minutes ago, MarkG said:

Is this something we should all consider in your opinion?

My design is to give my line distance from my tap point plus making the testing of the sensor much easier. Again you need a minimum of 5 feet of 1/8 inch air line for that reason longer is better. 

Edited January 9, 2021 by Mopar1973Man

[Doubletrouble]

Would you have some more detailed pics of your set up mike? I think I know what you did by the description but I like pics. Lol

[dripley]

2 hours ago, MarkG said:

My battery cables are original but look like they are in great shape still.  Truck just turned 150,000 yesterday.  How hard was your stumbling cut out?  Minor?  Major?  I don't want to rule anything out.  Thank you all so much. 

I did not have any cutting out or stumbling. Closest thing to that I ever had bucking at high load and rpm and that was from a clogging fuel filter. Surging and dead pedal were my biggest gremlins. No more though.

[MarkG]

Well, I'll prob get flamed for this but...when I installed my fuel pressure gauge I was aware of the pulse issue coming from the VP44 and didn't have the time at the moment to build out something like Mike did so I installed the sending unit in the FASS lift pump itself.  I change my filters at least once a year.  Couldn't see how there could be a big drop in pressure from the lift pump to the injector pump with fresh filters and the big 1/2" fuel line.

 

Made a B double E double R U N yesterday and hammered the go pedal again.  The truck ran much smoother than it had in past few days, I changed nothing.  It still wasn't running 100% clean but no where near the roughness it had been displaying previously.  What do you guys think of the VSS?  I read a couple threads now where that was the fix.  Any experiance with a failing VSS and symptoms out there?????

[Mopar1973Man]

Actually good spot for the pressure sensor its away from the VP44.

 

VSS does have any impact on fueling. I ran without a PCM before and also without a ABS module. No impact on power.

[MarkG]

Howdy all.  I was on the road for a few hundred miles yesterday and had an opportunity to experiment with the gas pedal and high freeway speeds.  Tried my best to again zone in on what the heck is going on with my truck.  Above I stated I suspected the VP44 could be causing the issue.  After yesterday's trip I'm thinking maybe it's the computer????  Just  a recap....the transmission and torque converter were replaced with a high quality upgraded remanufactured unit a few months ago.  The symptoms are exactly the same.  I was hoping that it was an issue with the torque converter, it's not, nor is it the transmission.  My batteries are fairly new, I did W-T's ground mods.  All connections are clean and tight.  There is a TC lockup switch on my dash.  The issue still happens with the switch in the locked position.  Fuel Filters are new.  Fuel pressure is rock solid at about 14lbs. 

 

So here's the observation in the best way I can describe it from yesterday's ride...Under hard acceleration at low speeds and speeds above about 68MPH (just cruising, not on the throttle) it feels like, if it was a manual, the clutch pedal is being pushed rapidly.  I think I can the engine RPMs slightly rise when this happens. 

 

Can anybody describe what it feels like when a computer is going bad?  Also wondering if maybe I could have a cracked pickup tube in the tank.  Wouldn't I see the fuel pressure fluctuate on the gauge though?  I love my truck and want to get past this.  Thank you all for your time, it's truly appreciated.

[wil440]

when it does it at low speeds is it in lockup ??

 

If I try to accelerate too hard in lockup either 3rd LU or 4th LU it slips and it feels just like what you say, I know you said you have a new convertor but what is a upgraded remanufactured unit?

 

A BD trans or at least parts and triple disk torq is on the list from DAP as soon as I can 

[MarkG]

18 minutes ago, wil440 said:

when it does it at low speeds is it in lockup ??

 

If I try to accelerate too hard in lockup either 3rd LU or 4th LU it slips and it feels just like what you say, I know you said you have a new convertor but what is a upgraded remanufactured unit?

 

A BD trans or at least parts and triple disk torq is on the list from DAP as soon as I can 

 

No.  Mine does it in 1st and 2nd not locked up.  Exact same symptoms that the original transmission displayed.  I'm 99.99% positive it's not the torque converter.

[MarkG]

My mind is grinding on this issue and I'm ready to force the solution.  I want my truck fixed and running tip top OR I want to smash the **** out of it with the backhoe at this point.  @Mopar1973Man...Let's get back to the Quadzilla train of thought as far as diagnostics go.  I've never had a tuner or telemetry to work with.  You mentioned the Quadzilla module records what's going on with the engine.  How confidant are you from those recording I (we) would be able to determine what the problem is?  I can justify the cost of the unit if I'm confidant it will help pin point my problem.  Still need to check the wiring harness VP->ECM but I'm almost positive everything there is intact.  It still looks new but will do my best to get that little pin adapter made for my multi meter and confirm soon.  Any input on the diagnostic abilities of the Quadzilla is absolutely welcomed.  Hope you all have a great Sunday and thank you for your time.

[JAG1]

On 1/23/2021 at 9:22 AM, MarkG said:

Howdy all.  I was on the road for a few hundred miles yesterday and had an opportunity to experiment with the gas pedal and high freeway speeds.  Tried my best to again zone in on what the heck is going on with my truck.  Above I stated I suspected the VP44 could be causing the issue.  After yesterday's trip I'm thinking maybe it's the computer????  Just  a recap....the transmission and torque converter were replaced with a high quality upgraded remanufactured unit a few months ago.  The symptoms are exactly the same.  I was hoping that it was an issue with the torque converter, it's not, nor is it the transmission.  My batteries are fairly new, I did W-T's ground mods.  All connections are clean and tight.  There is a TC lockup switch on my dash.  The issue still happens with the switch in the locked position.  Fuel Filters are new.  Fuel pressure is rock solid at about 14lbs. 

 

So here's the observation in the best way I can describe it from yesterday's ride...Under hard acceleration at low speeds and speeds above about 68MPH (just cruising, not on the throttle) it feels like, if it was a manual, the clutch pedal is being pushed rapidly.  I think I can the engine RPMs slightly rise when this happens. 

 

Can anybody describe what it feels like when a computer is going bad?  Also wondering if maybe I could have a cracked pickup tube in the tank.  Wouldn't I see the fuel pressure fluctuate on the gauge though?  I love my truck and want to get past this.  Thank you all for your time, it's truly appreciated.

I think either a few things..........

 

One is, you might need to test the level of AC Ripple in the system or try driving with a disconnected Alternator. Even tho the W-T harness mods were accomplished already. Do you have a way to test for it?

 

Another is running the lift pump directly off of the ECM factory lift pump power supply and the lift pump is overloading the system with a lift pump starting to go south. Bad connections/ connector in this area too can cause your problem.

 

The third thing is a bad fuel pressure gauge/ sender giving you false readings when in fact the fuel is dropping/ cavitating at certain levels. This brings up another list of fuel supply issues possible from module to the VP44. What has been done to the fuel delivery system can you elaborate on that? Including what type of fuel pressure gauge and if you have the needle valve etc. 

Edited January 24, 2021 by JAG1

[MarkG]

1 minute ago, JAG1 said:

I think either a few things..........

 

One is, you might need to test the level of AC Ripple in the system or try driving with a disconnected Alternator. Even tho the W-T harness mods were accomplished already

 

Another is running the lift pump directly off of the ECM factory lift pump power supply and the lift pump is overloading the system with a lift pump starting to go south.

 

The third thing is a bad fuel pressure gauge/ sender giving you false readings when in fact the fuel is dropping/ cavitating at certain levels. This brings up another list of fuel supply issues possible from module to the VP44. What has been done to the fuel delivery system can you elaborate on that? Including what type of fuel pressure gauge and if you have the needle valve etc. 

 

I did elaborate on all that earlier in the thread.  FASS Titanium lift pump.  new filters.  electric fuel pressure gauge with the sending unit plumbed into the FASS unit.  Shows a solid 14lbs of pressure.  I replaced the VP44 a few years ago with an Industrial Injection unit that looked like it was kicked around their shop floor for 10 years before they sent it to me.  Never impressed with that pump from the min I took it out of the box.  It was noisier than my original.  I should have sent my pristine original to Blue Chip, always kicked myself in the *** for not doing that.  I do have a fuel tank sump/outlet that I've been meaning to install for years but have not got around to doing so yet. 

 

I will search out how to test the AC ripple.  Thank you.

[JAG1]

Fass has been known to fail very soon after install. We have a recent situation that took out a new VP44. It happened to a truck Michael Nelson has on in his yard now. I believe Fass also does not provide a wire harness that gets the power draw off the ECM and onto the batteries as should be done. The dog gone lift pump can put AC ripple back into the system , although I have not studied this area enough yet to say, but running off the batteries protects the ECM with the correct protection relay,(also very imprtant)

 

Electric sending units for fuel pressure are also not so reliable and if your at a solid 14 as said, what is it doing on acceleration or cruising? I ask especially in your situation where your fuel pressure is in actuality a marginal pressure. It would normally be adjusted with the regulator to 19psi at idle so that hauling heavy running up grades will not allow the pressure to drop below 14 (very important). I find even the mechanical gauges to both my second gen trucks are off a little. One is actually 4.5 higher and the newer Isspro is showing 1 psi higher when tested at the vp44.

 

To keep perhaps shooting closer to the problem.... what was done to the fuel delivery? Half inch lines all the way? Screens and factory in tank lift pump removed? On the fuel pressure.... can you borrow a test gauge to test at idle and compare gauges?

 

One last note......my experience with electric sending units for fuel pressure readings is at the point I would maybe trust it for a month at most and would probably replace with a mechanical very soon. Do not put in the isolators neither they are unreliable as well. I do not think your problem is in the trans.

 

I think I'm going to catch hell from some statements made here...... so that's good anyway, getting you lazy bones that know a lot to help this guy before he takes a excavator to his truck.

Edited January 24, 2021 by JAG1