Cummins Loping After Being Put In Gear On Cold Start Up?

[Thundershot5726]

So I’ve been having this issue lately where after a cold start or more a first start after the truck has been sitting for a while, I wait a few seconds to let it build oil pressure, then put it in the drive.

It starts to lope, but it goes away after a few seconds.

It’s been happening ever since I put in a new HRVP44.

At first, I thought it was because of the injector lines because they were leaking like crazy.

Still, I’ve put brand new ones in stock size; even the cross-over tubes are brand new.

I am unsure if this would be normal with my work, but I don’t want to take any chances.

I have a 2002 Dodge RAM 2500 quad cab long bed with 210k miles.

It’s got 85hp injectors, brand new stock size cross-over tubes, brand new injector lines from Scheid diesel stock size, a hotrod VP44 from Industrial Injection, a FASS lift pump, and a built trans and a Spoologic “stage 2” turbo.

It’s got a brand new camshaft sensor and a brand new apps from Napa oil changes are always kept up on, truck has zero codes

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[Thundershot5726]

Seriously, why are people liking and thanking me but not my even replying whatsoever?

I seriously have no clue if this is supposed to be expected or if I need to replace something ASAP, I need help.

I posted the same thing on Cummins forum, but it just seems that nobody wants to help with this issue or won’t talk about it.

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[watersupply189]

Friend, it could be that some may not know the answer, and I just wanted to thank you for posting.

Hopefully, someone here will speak up who has experience with the injectors and the issue you're experiencing, etc.


2016 Ram Laramie 3500, G56, 6.7, CC, 4x4

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[Corkey]

I have limited experience with the 5.9's.

If it's loping, I will look at the exact parts you had already replaced, "injectors, fuel pump, lift pump," to rule out issues being fuel-related.

Monitor the actual vs. desired on the same HRVP44 because that is when the symptoms started.

It could be getting air sucked into a line or have a small fuel leak causing the hiccups.

Do kill tests on each injector or see if they deliver the correct amount for that cylinder.

I would point the finger towards the HRVP44 for the time being.

Was it new, reman?

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[Corkey]

https://industrialinjection.com/prod...44-pump-235-hp

?

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[Corkey]

Double-check that the cross-over tubes are at proper torque specs; this will also be a possible culprit for the symptoms.

Generally, for any fuel leak, you will smell a raw diesel smell under the hood, depending on the size of the leak.

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[Thundershot5726]

Yes, the injection pump is from the industrial injection, but it’s not the stock one.

The hot rod VP44 has more timing and is like such a pump but has the cam of the high output VP.

It’s done it before with the old VP, and the cross-over tubes are brand new now; the truck doesn’t leak any fuel.

Maybe the injectors went bad or are starting to somehow, but after today, I discovered that it is mainly.

It only does it when it’s cold, like today when it was 70° out.

I started the truck, waited a few seconds, and put it in gear, and it didn’t do it.

Also, how would I do a kill test?

Just take out the injector?

Or how could the fuel still go to that line?

Link to HRVP44 from industrial injection: https://industrialinjection.com/coll...-pump-80-100hp

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[Corkey]

A kill test is done with a decent scan tool.

The scanner disables the specific injector momentarily.

It might be just due to the real cold weather out.

Do you have a plug for a block heater by chance?

Or at least try to plug it in to see a difference on initial start-ups compared to unplugged?

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[Thundershot5726]

I’m wondering if it could be the ECM.

I’ve completely replaced everything with doing with fuel at this point, but still, when I’m driving, my rpm’s danced up and down a little even at idle, and I’ve heard people say that’s an ecm thing, but I don’t know if the ecm would cause a lope on cold start.

Would taking it to a dealer and having it reflashed and updated would be a good idea?

My exam has never been tuned or updated at all. It doesn’t even have the 3cyl high idle or anything.

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[Aj Grubb]

I'm pretty sure that advancing the injection timing beyond stock has a negative effect on the cold start and running manners of a diesel engine.

This might be the way it is with your hotrod pump.

Maybe let the truck warm up for a while or greturnto stock timing.

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