Denny Posted February 5, 2008 Share Posted February 5, 2008 I've got a problem that maybe somebody out there has had and cured. It is totally computerized naturally. It has a distinct ERRADIC miss from about 800 to 1000 rpm. Seems like it smooths out after that, but could just be motor dynamics.Only notice it while stationary. It's got plenty of hp. on takeoff pull, and can't hear any misses.It's got my dealer stumped. Got it 1 yr. ago, has done it since. in the last year they've replaced injectors, run fuel psi.,had all 6 injector pumps out, replaced #6, broken spring keeper. Run the valve clearance,twice, last time found a rocker shaft gaulded, replaced it, flashed the computer, set it to min-max hp. Wierd thing is , it does'nt do it until warmed up. Dealer has talked to the factory, Nowhere to turn. I'm thinking electronics, Please help if anybody has had the same thing, THANKS. Quote Link to comment https://www.bigmacktrucks.com/topic/3388-erratic-miss-in-2001-e-7-427/ Share on other sites More sharing options...
Mackpro Posted February 5, 2008 Share Posted February 5, 2008 We have seen this complaint many times and have also talked to the factory engineering several times. At one time they did have a download for this "rough idle" as they call it but I was thinking it was for 1999/2000 models and the 427 seems to have it worse than any of the other HP's. We have seen it where the whole truck shakes but as soon as you idle it up it goes away. We have never been able to get one to quit doing it. We did put a 100psi fuel valve on one and it helped but other than that no luck here. Quote Link to comment https://www.bigmacktrucks.com/topic/3388-erratic-miss-in-2001-e-7-427/#findComment-16796 Share on other sites More sharing options...
Gambi80 Posted February 5, 2008 Share Posted February 5, 2008 We have seen this complaint many times and have also talked to the factory engineering several times. At one time they did have a download for this "rough idle" as they call it but I was thinking it was for 1999/2000 models and the 427 seems to have it worse than any of the other HP's. We have seen it where the whole truck shakes but as soon as you idle it up it goes away. We have never been able to get one to quit doing it. We did put a 100psi fuel valve on one and it helped but other than that no luck here.I've stood beside a couple 99/00 Macks at idle and they sounded pretty rough too...was always told that's just how it is. They ran like a bat outta hell but sounded like hell at idle. Quote Ever wonder how a blind person knows when to stop wiping? Link to comment https://www.bigmacktrucks.com/topic/3388-erratic-miss-in-2001-e-7-427/#findComment-16799 Share on other sites More sharing options...
rw613 Posted February 5, 2008 Share Posted February 5, 2008 we have several of the e tech engines they all do it we also several of the older e 7 engines and you can hardley teel there running nature of the beast we have changed fuel pressure on sometimes it helps Quote Link to comment https://www.bigmacktrucks.com/topic/3388-erratic-miss-in-2001-e-7-427/#findComment-16800 Share on other sites More sharing options...
Denny Posted February 5, 2008 Author Share Posted February 5, 2008 Thanks a lot for the replies guys, My 95 just purred right along, but it was MECANICAL pump. Still the best!!! It eases my mind somewhat to know that I'm not the only one that idles rough. Quote Link to comment https://www.bigmacktrucks.com/topic/3388-erratic-miss-in-2001-e-7-427/#findComment-16802 Share on other sites More sharing options...
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