Community Forums

ProjectPro · 11-14-2016, 12:35 PM

I occasionally get "Check Engine" and "Stop Engine" lights, but by the time I get to the side of the road they go off. It seems to happen the most when the weather is cool or cold, and when first starting out for the day, under acceleration to come up to freeway speed. If I tool along at about 55 MPH for 15 minutes to a half hour, I can return to 65 MPH with no alarms. The gauges are all normal and there seems to be the same power whether the alarm sounds or not.

I had them read the codes while I was attending Camp Freightliner this spring. They found codes for Low Boost and No Boost, and suggested I take it to Cat.

Since it seems to be running fine, I'm guessing that the problem is with a sensor, not the turbo. Anyone had a problem like this? Anyone know what sensor(s) could report these problems?

hayward3411 · 11-14-2016, 02:06 PM

My Cummins ISB 6.7 was doing the same thing, after dealing with it for years (to remove code had to restart engine). I contacted Cummins and set up an appointment to update the software. I had the original 2008 version 14 and they were up to version 41, it was explained to me that each version could have up to 200 software changes. Fixed my problem. I was told that the original version 14 software had the parameters set too tight resulting in throwing codes. Total cost was $104.00

JNSNWT · 11-14-2016, 05:32 PM

When you got the "new and improved " software did you notice any change in MPG or performance ?

I've not checked into what software version I have because I've read all the horrror stories about MPG going doown after an upgrade.

But I'm not getting any check engine lights either.

Pusherman · 11-14-2016, 05:43 PM

Quote:

Originally Posted by ProjectPro

I occasionally get "Check Engine" and "Stop Engine" lights, but by the time I get to the side of the road they go off. It seems to happen the most when the weather is cool or cold, and when first starting out for the day, under acceleration to come up to freeway speed. If I tool along at about 55 MPH for 15 minutes to a half hour, I can return to 65 MPH with no alarms. The gauges are all normal and there seems to be the same power whether the alarm sounds or not.

I had them read the codes while I was attending Camp Freightliner this spring. They found codes for Low Boost and No Boost, and suggested I take it to Cat.

Since it seems to be running fine, I'm guessing that the problem is with a sensor, not the turbo. Anyone had a problem like this? Anyone know what sensor(s) could report these problems?

I had a similar problem on my C7 2 years ago. Stop Engine light was coming on when climbing grades, mostly. It would then clear with no apparent issues.

I took it to a CAT dealer and they diagnosed that the turbo boost waste gate valve was sticking. They disassembled it, cleaned it, and reassembled the unit. I have not had a problem since.

They charged about 2.5 hrs to diagnose and repair, but there were no parts charges. I think they did a great job diagnosing and rectifying the problem. I am a happy camper.

P.S. A stuck waste gate valve does no damage to the turbo or engine (as I am told), and in fact boosts power. Problem is with the emissions issues with the ECM. Thus why the engine just purrrs along, at least under my circumstances.

hayward3411 · 11-15-2016, 03:36 AM

No noticeable changes in fuel mileage or power. I have been averaging about 11 MPG when not towing.

twinboat · 11-15-2016, 05:01 AM

Classic symptoms of partially blocked filters.

If not done recently change the fuel filters.

Very expensive engine to ignore the STOP engine warning.

ProjectPro · 12-22-2016, 12:20 PM

Took it the local Cat dealer. They inspected it and said that the waste gate was completely frozen, and that it was beyond fixing. In this engine the waste gate can't be changed independently from the turbo, so now I have a new turbo and my wallet is 2K USD lighter (plus labor).

I must say that it seems a lot peppier now, and the alarms are gone.