cat c7 power loss- need suggestions

[n4hwl]

I am from Tennessee and have driven this motorhome about 39K during the last 6 years of so since I bought it. I arrived in Denver Colorado about 2weeks ago. I noticed a very noticeable decrease in power when I arrived. I took the motorhome to the local Transwest Freightliner dealer that is an authorized Cat repair facility. I now have a new turbo charger, and a completely new set of injectors and a new wastegate controller. I picked up the motorhome today with the assurance that everything was fine. Something is definitely still wrong . It has very little power on acceleration and really just lugs along until I can get up to about 2000 rpm. I know I am used to the power back at home under 1000 feet elevation and I am now in Denver at about 5000 feet but have a hard time believing that the severe loss of power is entirely because of elevation. I am taking it back to the Freightliner shop tomorrow.

The question is how much loss of power have you folks seen on a properly working turbo charged diesel at the elevations I am at here in Denver? I know I will see some but this thing is a real dog when starting off. I was going up a little rise from a stop light and had my foot to the floor and I did not think it was going to get above 1500 rpm and get out of first.

Any suggestions or comforting words would be appreciated.

Thanks

Stuck in Denver

Ken

[n4hwl]

Yep I am fixed and drove from Dennver to Moab. UT along I 70. The old ecm programming was not communicating with the new injectors ( I was told} The update on the ecm allowed the injectors to start working properly. All I know is that everything seems to be working. I have another 2 or 3 thousand miles to put on this thing before I get home. That should tell me if it is going to hold together.

Ken

[Big_Katuna]

He's fixed and on the road.

[John_S_]

Have they checked the CAC. A crack or leak there can reduce the power.

[AH64ID]

They are blaming the WG on an ECM tune?

[n4hwl]

I believe them when they said the wastegate was stuck open. This is the first time I have been at this altitude. I usually drive around the southeast usually below 1000 ft elevation. It is possible that the boost has been down a long time and driving at lower elevations it has not been a big deal. It seems to be running fine now. I am in Evergreen Colorado now and will head west on I 70 very shortly. I will find out up around the continental divide it the turbo is doing its job.

Ken

[AH64ID]

Have you had the rig at altitude before?

I'm wonder if the ECM flash was the issue in the first place.

[n4hwl]

Big Kahuna

I think if I have a choice next time I will go to the Cat dealer directly. At least Cat themselves should be up on their own engines

Ken

[noteven]

Most truck shops will not flash an engine ECM without the owner's permission. It is also good practice to ask them to check for updates and explain to you what the update is for before they do it.

Glad to hear the engine is fixed.

[Big_Katuna]

Thanks for the update and glad you are back on the road.
Sounds like another marginal Freightliner shop. I have not been impressed with any I have used.

[n4hwl]

Final resolution to problem.

The problem this week is that old program in the ecm that seemed to be the one that was in it when the engine was built had never been updated. This old version in the ecm would not talk to the newer injectors and they were not working properly. I killed 4 days in Denver just because they did not reflash my ecm with the new software when they put in the new injectors. My question is why did they not know they needed to do this. Either 1. Caterpillar is not keeping Freightliner updated on what these engines need as far a software or 2. Caterpillar is keeping Freightliner updated and Freightliner is not keeping things straight. Well either way I am headed over the Rockies today and things seem to be working fine. Thanks for all the help

Ken

[Big_Katuna]

My FL does not have a turbo boost Guage. Another reason to get the Silverleaf setup.

[Ivylog]

Oh boy... wait two weeks to get in and they change a bunch of stuff (at your expense?) and no improvement. Ken, you should not notice any power loss with a turbo engine up to 10,000'. Even on a 04 you should have a turbo boost gauge and at full throttle and over 1500 rpm you should have over 20 psi of boost. Around 04 is when the 3126 became a C7 but both should have a data port for finding codes. What codes did they find? What boost pressure are you getting?
In the first post about your problem it sounded like this lack of power was noticed all of a sudden while you were in Denver??? You also posted that unfortunately it was not loose boots/clamps so we can assume they did a pressure test. It bothers me that they replaced your injectors because of a bad turbo and waste gate (even if they were bad which it turns out they WERE NOT). I would not be as calm as you seem to be.
Twomed suggest checking for air in the fuel because of a problem I had with lack of power on my Cummins ISL last month. It turned out to be a small amount of air in my fuel from a fitting a the fuel tank which was tight, but was letting air in. I found the problem by putting a short piece of clear tubing before the second new fuel filter after replacing the lift pump which did not fix the problem.
I'd be finding someplace that can read your codes as it could be as simple as a bad sensor and once I had a code it is what helped me find my problem.

[Mandalay_Parr]

Maybe take it to a Cat engine dealer.

[n4hwl]

No check engine lights at all. Just low power. Dropped it off at Freightline this morning and we will see. I know things break and things happen but I have been here in Denver 2 weeks and am ready to get on down the road.

Ken