2009 cm 871 has us stumped

[Rawze]

CM870/871 ecm's are notorious for being flaky and cutting out exactly like you describe, as they get intermittent inside them. It is a well known issue.

A certified reman will always come with a brand new circuit board in it. This is because the OEM (the red engine maker themselves) cannot be bothered with repairing them internally, but only re-use the outer metal frame. This also means the it will also NOT likely have this issue from the get go, as the entire circuit board inside it is brand new ... . so ...

Where did the replacement ECM come from?... the stealers#it?... or somewhere else?.

==> 80% chance for it to be flaky these days if you got it from NON-oem certified stealers$it.

That is most likely problem #1 with it dying.. If it has this issue, then smacking in it its upper left corner, or upper face (almost hard enough to dent the casing) when its working will make the electric fuel pump cut out and/or engine suddenly die if it is idling.

NOTES::: > ALWAYS ALWAYS have the ECM pre-flashed by the stealers$it, ready to ju=st hang on the truck and drive away before taking it away form them to put on the truck. You will end up EATING $2800+ dollars if anything is wrong with it while you are waiting on a warranty claim otherwise.

AND ALSO ... after the new ecm is installed.... run the truck for at least 10 mi9ns after installing it + smacking it a few times to ensure you did not get a flaky one... BEFORE YOU RE-FLASH IT WITH ANY CUSTOM SOFTWARE OR EVEN TOUCH IT WITH ANY DIAG. TOOLS.

Next... is red flag number 2 in your post above ...

The delete program is 90%+ likely to be harmful to the engine/truck.. I don't care how many years it ran like that.

The only way to be sure that your not putting back in some engine killing complete trash is to copy the program out of the old ECM and e-mail it to me for a proper full review of what someone did in there.

One of the major causes for the ECM to become flaky like that is for no one to change the crank shaft damper when its due. higher frequency vibrations set in and cause the ECM to become flaky if this is not done at 500k miles (or equivalent hours).