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+--- Thread: Timing valves (/showthread.php?tid=8787)
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Timing valves - TerryB - 03-09-2023
I want to replace timing valves on my CM570. Has a rough idle sometimes, maybe misses a little. Nothing I've tried has fixed it. Ran overhead, it was nearly spot on. Did the test to check for compression leaking through injectors. No bubbles. I was going to try replacing timing valves, can't find any. All Cummins would tell me was they were not available. I didn't look for anything except new. Are there reman valves? I don't know why I called them valves....Actuators
RE: Timing valves - TerryB - 03-09-2023
Forgot to mention no engine light or fault codes. Engine runs fine other than idle speed. Horsepower and all programs haven't been messed with.
RE: Timing valves - Bengy88 - 03-10-2023
http://rawze.com/forums/showthread.php?tid=7747&pid=67948#pid67948
and
https://rawze.com/forums/showthread.php?tid=110&pid=619#pid619
This should tell you if you need to replace them or if your about to waste your money.
RE: Timing valves - TerryB - 03-10-2023
Thank you! I had not seen that.
RE: Timing valves - TerryB - 04-30-2023
I removed timing and metering valves and inspected per Rawze's video. I really didn't see anything wrong with them. May have saved me a good chunk of $. But my problem still exists. So the injectors have passed compression leakage test, the overhead was adjusted nothing was found to be out of adjustment if you compare paint marks from before to after. Actuators don't appear to be faulty. What's left? Could it be ecm sending faulty signals to timing/ metering actuators? Would there be faulty codes if that were the case?(There are no codes). Can the injectors be bench tested? Is it worth doing that if they can be? I tried to locate a faulty cylinder with a temp gun on the exhaust manifold. Just can't find much of any temp difference. It doesn't sound like a dead miss. It just sounds like things are not quite right when idling, just like the timing is not always quite right but that's strictly a guess on my part. Dang thing runs great going down the road. Honestly it's more embarrassing than anything else on how it sounds when idling. Had straight pipes which make it more noticeable.
RE: Timing valves - Rawze - 04-30-2023
you sure you aren't just chasing a ghost?...
after 980,000 miles, mine idled a bit rough.
After I inframed it, changed nothing whatsoever in the fuel system, even re-used all injectors, old cams, literally everything except the head itself and putting in a new overhaul kit,.. it suddenly idled smooth again.
It was obviously the head itself that was wearing out, making it idle a bit rough, and it didn't hurt a thing.
RE: Timing valves - TerryB - 04-30-2023
That's a fair assessment for sure. The reason I think there's something not right is because sometimes it idles completely smooth. Those occurrences are much less than idling rough. I would guess 80% of the time it idles rough. And I can't come up with anything being different when it idles smooth.
RE: Timing valves - Luckyjayb - 05-01-2023
(04-30-2023 )TerryB Wrote: That's a fair assessment for sure. The reason I think there's something not right is because sometimes it idles completely smooth. Those occurrences are much less than idling rough. I would guess 80% of the time it idles rough. And I can't come up with anything being different when it idles smooth.
Just an afterthought, but with it being a CM570, are you getting any trash in the fuel filters. The reason I ask is are the fuel supply lines starting to deteriorate and come apart on the inside. I’ve chased ghosts before and found that as one cause. Also, are you getting the proper fuel pressure? The fuel pump could be starting to fail. I had one fail on my CM870 and Cummins says the gear on the pump is supposed “some resistance” but doesn’t specify exactly what they mean. Just a thought but not saying replace it to just to replace it.
RE: Timing valves - TerryB - 05-01-2023
The fuel filters have been replaced multiple times, didn't see trash in the filters plus new filter didn't make any difference in the way it idled. The electric pump is supplying about 12-14 psi to the gear pump. I don't know what kind of pressure the gear pump is putting out. That I have not checked. I would imaging that pressure fluctuates quit a bit depending on engine load. Fuel supply lines have all been replaced.