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-   -   P0251-shop thinks its timing chain stretch? (https://www.dieselplace.com/forum/63-gm-diesel-engines/21-6-5l-diesel-engine/975526-p0251-shop-thinks-its-timing-chain-stretch.html)

ak diesel drive 05-03-2019 12:26 PM

AFAIK TDCO is never reset unless commanded. the resistor value on OBD1 is checked every 50 starts, on OBD2 not so

dauber 05-04-2019 09:09 PM

Quote:

Originally Posted by ak diesel drive (Post 9817760)
AFAIK TDCO is never reset unless commanded. the resistor value on OBD1 is checked every 50 starts, on OBD2 not so


ok. So if this is true something is changing my timing.

dauber 05-04-2019 09:19 PM

I just completed the following:

-ran clear hose from T-Valve. Fuel ran into container with no air bubbles present. I closed the valve and opened the air valve on top of the filter and fuel spurted out.
-changed PMD with my spare. #5 resistor is in place.
-searched for optical filter and I do not see one.


Drove it a short distance and ran fine. I am going to hold off on changing the new Rock Auto HB and pulley I received until I make sure this code is not coming back. I will drive it for a few days and see if code returns.

OkDually 05-04-2019 09:24 PM

Quote:

Originally Posted by dauber (Post 9817920)
I just completed the following:

-ran clear hose from T-Valve. Fuel ran into container with no air bubbles present. I closed the valve and opened the air valve on top of the filter and fuel spurted out.
-changed PMD with my spare. #5 resistor is in place.
-searched for optical filter and I do not see one.


Drove it a short distance and ran fine. I am going to hold off on changing the new Rock Auto HB and pulley I received until I make sure this code is not coming back. I will drive it for a few days and see if code returns.

The clear fuel line needs to be installed on the return side of the IP to properly find air in fuel, as shown in this link:
https://www.dieselplace.com/forum/63...ml#post7305306

dauber 05-04-2019 11:21 PM

Quote:

Originally Posted by OkDually (Post 9817922)
The clear fuel line needs to be installed on the return side of the IP to properly find air in fuel, as shown in this link:
https://www.dieselplace.com/forum/63...ml#post7305306




thank you. I will do that tomorrow

ak diesel drive 05-05-2019 02:38 PM

I'd be doing the tests for the CPS and OPS

dauber 05-11-2019 02:01 PM

update:
One week of driving and no code. I am hoping it was the PMD. The PMD I put in was the one I used for years with the old pump. After I replaced the pump in December I used the PMD that came with the rebuilt pump. The engine seems to run quieter and smoother. Crossing fingers







Quote:

Originally Posted by ak diesel drive (Post 9818050)
I'd be doing the tests for the CPS and OPS


CPS replaced in December by shop as they could not get it timed after I replaced the pump until they changed it out. I will replace OPS if i get code again, thanks.

JMJNet 05-11-2019 04:06 PM

As a test, you can put the PMD that caused the DTC and see if that is still causing the DTC.

On the other hand, you may not want to disturb anything except probably get a new PMD for spare.
Now, make sure you test it in the truck driving for a few weeks before retiring it as a WORKING spare.


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