Ram HO Cummins no power at first start up

[Dromleski]

I was hoping for some advice. My 2019 Ram HO Cummins is starting to have an issue. I started it up the other day and started driving and realized it would accelerate. I even floored it and it would go (about 1000 rpm max). After a couple minutes it was back to normal. Almost like the pedal wasn’t working. I hooked up my scanner and had no codes. Next day I disconnected the battery for several hours hoping maybe the computer might refresh? Started it up with my scanner in live mode and sounded great, pressed the accelerator and wouldn’t rev past 1000rpm, like a rev limiter holding it back. Looked at the scanner and the pedal is working. Reading between 2%-100% smoothly through the range but not the engine. After about a minute or two it went to normal ind would rev all the way up no issues. It seems like it’s the computer. It’s a 2019, all original no mods at all. It has had the cp3 recall performed about 10,000 miles ago. It has 60,000 miles on it now. Always been a great truck and never had an issue. Hopefully someone could give some insight. Thanks

 

[PRS]

Compare commanded fuel rail pressure to actual fuel rail pressure. If you disconnect the FCA on the HPFP, the pressure should go to 26k.

 

[Dromleski]

Thanks for your reply, this morning I got up and checked what you said and of course it ran fine this morning. I still hooked up the computer and read the pressures. Both were pretty close bouncing around. Then I still unhooked the wire and started the truck. The commanded was 14500 and actual 16180 at low idle speed. I shut it off as soon as I got my readings. Hooked up the wire and went on a test drive while viewing the pressures. Both numbers stayed pretty close and under heavy load pressure was up to 24000-26000psi. I guess I have to wait for it to mess up again to actually see what it is doing. Thanks again. Any other ideas let me know and I’ll keep you posted.

 

[johnnyroastbeef]

@Dromleski I had the same issue multiple times this past winter. Put it in Drive and zero power, barely get it to move. I'd stop and let it warm up a little more and it went back to normal, so something is stuck closed. The Issue went away this Summer which is super odd...but I do have an Underboost CEL on. I am sure they are related. Did you ever figure this out?

 

[Dromleski]

@Dromleski I had the same issue multiple times this past winter. Put it in Drive and zero power, barely get it to move. I'd stop and let it warm up a little more and it went back to normal, so something is stuck closed. The Issue went away this Summer which is super odd...but I do have an Underboost CEL on. I am sure they are related. Did you ever figure this out?

Yes, I hooked up my scanner and checked a few things that I thought it could be and found that my VCT demanded position was around 80%and fluctuating with throttle but my actual position was stuck at 13%. For some reason I didn’t get a code and after a minute or so it would run perfectly and the actual and demanded position stayed the same. Turns out it was a failing actuator. I took it off while it was acting up after I cut the truck off and drained the coolant and the vanes in the turbo strokes real easy so I cleaned the sealing surface good and installed a new actuator. The old one had some slights signs of a coolant leak (which causes a lot of issues for an actuator). That was pretty easy to do. My other problem was when it was acting up I’m sure it ran rich and dumped out a lot of smoke which clogged up my DPF. Gave me a code p242F which the computer thinks is full of ash. Tried to force a regen but can’t with that code. So tonight it won’t have that issue with the DPF anymore. But the truck ran good with the new actuator and no more hesitation.