Engine/Transmission (1998.5 - 2002) Well talked about, IDLE MISS ....

[KGrotte]

I have been reading alot of past threads about the miss at idle (01 cummins). I recently changed my HRvp44 with another HRvp44. I had a miss and for the life of me could not figure it out so i sent the pump back and they built a new pump and burned a different MAP in it. I am running MACH 7's but i have had them out and tested. Now i am having the common random miss at idle and seems to be there while driving once in a while also. it is not constant and seems to be worse when the engine gets warm. I have heard people saying the ECM. i am thinking of trying a different one but not to shure if the previous owner had changed anything with a programer hence i am afraid if i try a different ecm the beast will not run right at all. ANY IDEAS ??? I was running an edge comp but it is unhooked until the warranty is up on the new pump. I do think the apps is going down hill i had the surging issue and reset the apps and has seem to be better but not to shure if the apps will lead to a miss. my main question is do programers change peramiters in the ecm or not. . any ideas is appreciated... Thanks

 

[waltk]

From my very recent experience...



My 99 had a miss at idle that I could not track down.



Then, completely unrelated, I learned bad things happen when a Crank Position Sensor (CPS) gets old here in New York (as in comes apart and takes out tone ring), so for piece of mind I changed it at 260k miles, the miss is now gone.



Now, you don't have a CPS, but you do have a cam position sensor. I really don't know if it functions they same as my CPS (in 99 the Cam was for diagnostic only, no fuel injection input), but you might look there... before dropping the cash on an ecm.

 

[BrooksElder]

I have been chasing a miss at idle for over six months. I replaced the injectors, vp44, airdog w/ new lines from draw straw to vp, reprogram ecm, valve adjust no change still random miss. I got ****** of and pulled the head this weekend. Machine shop just called me and said valve guides were either wore out or fell out and they were bad enough to cause a miss. This might not be it but I sure hope so.

 

[KGrotte]

I am going to do some digging this weekend. I do have a aftermarket toner ring on my big cam so i am going to check that out but I am not to shure because it does not miss all the time and it also miss's at constant RPM. If i hold it dowm a little approx. 1700rpm it miss's in surges it can miss very rapidly for a few seconds then go away and other times it will just miss once or twice. I have had allot of head work done High PSI seals,guides and seats as i used to have twins. I am not saying something is haywire in the head but did not see any issues the last time i had it off (fire ringed the head). Machinist said there was very tiny crack in one of the exhaust ports but that was the first time the haed was off and it has not changed the last 3 times he has played with it. I have never been able not to fix the beast, now i just have days i want to sell it Thanks again for any info