CM871 runs on after shut down

[Kenworth509]

Hey guys I’ve got a cm871 that we found had leaking injectors so we replaced all 6 injectors and completed an over head set at the same time, we also replaced the fuel stop solenoid as well.
The issue we have is it still runs on once it’s hot and takes 5-10 seconds before it will stall out and when it is running it sounds like it has a miss fire. Could this possibly be a bad cylinder head?

[Bengy88]

(11-02-2023 )Kenworth509 Wrote:  Hey guys I’ve got a cm871 that we found had leaking injectors so we replaced all 6 injectors and completed an over head set at the same time, we also replaced the fuel stop solenoid as well.
The issue we have is it still runs on once it’s hot and takes 5-10 seconds before it will stall out and when it is running it sounds like it has a miss fire. Could this possibly be a bad cylinder head?

Timing and metering actuators? There is a procedure to check these floating around on the forum.

[Rawze]

(11-02-2023 )Kenworth509 Wrote:  Hey guys I’ve got a cm871 that we found had leaking injectors so we replaced all 6 injectors and completed an over head set at the same time, we also replaced the fuel stop solenoid as well.
The issue we have is it still runs on once it’s hot and takes 5-10 seconds before it will stall out and when it is running it sounds like it has a miss fire. Could this possibly be a bad cylinder head?

(CM570,CM870, CM871, non common-rail engines) ...

just some fyi: ...
The fuel shut-off solenoid will NOT be the cause of the engine running for several seconds too long after key off!!!. Matter of fact, it is likely the fuel shutoff solenoid that is operating normally, making it only last 10 seconds, and not a whole lot longer ...lol.

The engine does not need the fuel shutoff solenoid whatsoever to shut off the engine. You could take its guts out and the engine would shut off just the same as it did before doing so when the rest of everything is healthy. - Matter of fact, my own engine has not even had a fuel shutoff solenoid for about 5 years now. I gutted it myself after it went bad (with zero warning) several years ago to get me off the side of the road, and I never bothered to fix it. My engine shuts off just fine.

The fuel shutoff solenoid is only a back-up/secondary safety device and is not used as a primary means to shut the engine off. The engine has has several seconds of lag before starving itself of fuel, even if someone were to suddenly unplug it.

=================

First of all, leaky injector(s) will NOT cause the engine to run after key-off like that.

It begs the question of how competent the shop was that did the work, if they even suggested that leaky injectors was the cause. Someone has to be totally clueless to suggest this on a CM871.

SO ... HOW did you test for, and determine that it had leaking injectors???.

- because here is a proper test procedure for them without even having to remove them that many repair shops have no idea how to do properly. They end up wasting a truck owners moneys ...
ref: http://rawze.com/forums/showthread.php?t...8#pid67948

AND DID ANYONE BOTHER TO TEST THE NEW INJECTORS AGAIN AFTER THE INSTALL???!!!>

ALSO... it takes some kind of clueless fool to tell you that a bad head is going to make it keep running like that too!!!> -- again.. incompetence on a repair shops part and lack of proper understanding on how the damn engine works!.

Here is the answer...
When the timing and metering actuators wear out, or are dirty internally, they cause exactly this issue, allowing fuel pas them and into the head/injectors, keeping the engine running/stubling longer than it should after key-off. (usually runs like s$it too, because the ecm is commanding 0 fueling and is no longer setting the injection timing any more). Leaky actuators also weakens the engine brakes, and will eventually cause harm to the cylinders.

Checking actuators: http://rawze.com/forums/showthread.php?t...619#pid619