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Lope at Start up? VP44?

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99 Ram 2500 4x4 auto 5.9 24V  bought it with 89K on it now has 116K.  The Issue I have is intermittently when it starts it has a ideal lope for about 5 to 10 seconds then ideals normally which around 740 -750 rpm... occasionally 800 rpm...  The problem is/was magnified when I installed 75HP injectors... bigger lope like it had a big cam in or something... but again it would ideal normal after 5-10 seconds on it own or if gave it some pedal... it would also like to stall when putting it in reverse with the 75hp injectors sometimes... the problem is only at start up truck runs fine other then that... I put the stock injectors back in and still does it just at a smaller lope...(problem has not worsened with time)  I really would like to run the 75hp injectors but the loping is like a pulling truck and the stalling is annoying... any ideas?

thx guys

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Mine loped after my 60 +HP injector install, then I popped the hood and found 2 of the injector lines were leaking where they screw into the head. Any codes? Start there. Since this was a problem previous to the injector install, and it get's better with fuel, it could be a fuel delivery problem or APPS problem.  

What other mods have you done to the truck apart from the injectors? We need to know what all you have so we can help figure this out. Any programmers? What is your fuel pressure looking like? That might help determine the health of the VP44.

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What other mods have you done to the truck apart from the injectors? We need to know what all you have so we can help figure this out. Any programmers? What is your fuel pressure looking like? That might help determine the health of the VP44.

ok gotcha... edge juice/attitude CTS, AFE cold air intake, AFE Bladerunner manifold, 5" mbrp turbo back, Raptor 150 lift pump with big line kit...  

I took edge off line it still does it... I also think I had the little bit of the lope when I first got the truck before i did anything to it... FUEL pressure never really goes below 13psi... I have it set around 16psi at idle... what i do not understand it is not consistent it does not do it all the time...  like it said if i put the 75 hp stick exaggerated.  this video link is what it does with the 75 hp sticks in...  3 separate clips first one normal start 2nd lope, 3rd normal again... idle rpm stabilizes on its own or if i push past idle.  notice it stablizes at 750ish rpm not 800.

Edited by Huskiemuskie

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Mine loped after my 60 +HP injector install, then I popped the hood and found 2 of the injector lines were leaking where they screw into the head. Any codes? Start there. Since this was a problem previous to the injector install, and it get's better with fuel, it could be a fuel delivery problem or APPS problem.  

ok thx... no leaks, and no codes, maybe a apps low voltage code once or twice if i recall in the past... nothing lately... what type of fuel delivery problem... here is a video of what it does with the 75 hp sticks installed... these are 3 consecutive starts...  

ok thx... no leaks, and no codes, maybe a apps low voltage code once or twice if i recall in the past... nothing lately... what type of fuel delivery problem... here is a video of what it does with the 75 hp sticks installed... these are 3 consecutive starts... https://vimeo.com/49471434

I just did some tranny work and now my truck almost stalls out when I put it in reverse too. I have also had low voltage codes from my apps. I will replace my apps today with a Timbo and report back.

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I just did some tranny work and now my truck almost stalls out when I put it in reverse too. I have also had low voltage codes from my apps. I will replace my apps today with a Timbo and report back.

ok I am very interested how that works out for you.... please report back thanks!  BTW I checked my apps voltages this morning... all appears normal.  linear voltage increase from idle to WOT.  .040 - 3.6v

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is this only at cold start up, or anytime it's started?

anytime... maybe more often when warm...

ok I am very interested how that works out for you.... please report back thanks!  BTW I checked my apps voltages this morning... all appears normal.  linear voltage increase from idle to WOT.  .040 - 3.6v

I'm not getting any voltage from my Timbo APPS, I need to do some trouble shooting...

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Have you pop tested your injectors to verify them?

Hi Mike BTW did your high idle mod a year or so ago and it work great! I talked to ya on the phone once about it...  (Also this loping issue existed prior to that mod...)

I mentioned that they were 75hp's actually they are Industrial Injection Bosch R1 honed X 3 85HP injectors. I bought them brand new from XDP... It will lope with the stock injectors as well just not as noticeable/dramatic... the video is with the 85's installed... after the first install I did take them back out and had them pressure/pop tested and balanced within three bar of each other by Wimer Fuel Injection, Sandy Lake PA...  I put them back in after the testing and no change still lopes like video... strange part as always it is intermittent...  Here are the pop testing results...  before and after numbers on the 85hp injectors:  

300-310

296-311

290-309

310-310

322-309

296-308

(side note I do not think the VP is the original...) 

 

"Wimers  fuel injection"..

 

small world!  working with them right now on  a  Simms inline pump-  converted  to  P-pump  plungers and barrels..

  • Author

"Wimers  fuel injection"..

 

small world!  working with them right now on  a  Simms inline pump-  converted  to  P-pump  plungers and barrels..

Wow! indeed.  Good folks!

OK so I have the same issue but it only happens to my truck when I jump in it start it and put it into gear right after starting it. If I let it run for a second or two then put it in gear nothing happens. Mine has been doing this for almost 8 months. I've tried new apps, trans valve body, and 3 sets of injectors. I figured it was in the VP and when it died I would deal with it then.

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OK so I have the same issue but it only happens to my truck when I jump in it start it and put it into gear right after starting it. If I let it run for a second or two then put it in gear nothing happens. Mine has been doing this for almost 8 months. I've tried new apps, trans valve body, and 3 sets of injectors. I figured it was in the VP and when it died I would deal with it then.

Sounds exactly what mine does as well... the same way also! 

 

Are you running stock injectors?  I have the stock ones back in mine

Does it do it every time or intermittent?

....shoot. I hope it's not the VP. Mine doesn't lope, but when I put it in reverse from a coldstart it almost stalls out. As soon as it's warmed up it doesn't stall in reverse. This just happened to me last week when I got my triple disc installed .

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Double check you fuel pressure Edge Juice has been known to inaccurate on fuel pressure sensors and be much lower or higher causing some of your issues. I would hook up a mechanical gauge for testing.

  • Author

Double check you fuel pressure Edge Juice has been known to inaccurate on fuel pressure sensors and be much lower or higher causing some of your issues. I would hook up a mechanical gauge for testing.

Ok I will do that... I also have a low fuel pressure switch installed... I have a rapter 150 so it should be pushin more than required...

 

I am just wondering... At start this lope will resolve itself without throttling... in just a few seconds maybe 5-8secs....  So if APPS voltages are correct...? (I rang them out at  .40 & 3.7v with no dead spots)

Should the ECM idling software be talking to the VP injection computer telling it to idle and how much fuel to meter to idle at 800rpm...?  am I correct in that thinking...?  If so maybe the VP is trying to do what the ECM is commanding but is not for some reason... ?   I should idle at least 800rpm... mine sometimes rarely idles at 800ish...  but more often than not 750-760ish...  I am just wondering if the VP is having trouble managing idle rpm at start up... (maybe this is all related somehow ??? ) 

 

I do normal to above normal oil and fuel filter changes... no H2O or dirt in filter canister anytime that I have changed it... 

I've bleed lines, pop tested injectors, changed injectors, crank position sensor, took edge juice off line with no effect... I have a new cam position sensor to hard to get to so have not done that yet...

So I'm running 100hp injectors now. This issue started with my RV275 injectors changed them out to 75hp still an issue then went to DAP 100hp sticks with no change. The one unique thing I have noticed is that if I let the truck run for a few seconds then put it into gear everything is fine. If I jump in fire it up and throw it into reverse real quick it will lurch or lope. Fuel pressure always monitored from mechanical gauge readings haven't changed much from 17 psi at idle to 15.5 wot.

So this doesn't matter of the engine temp or runtime, hot or cold outside. I can make this happen on command anytime I start my truck.

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