krismoriah Posted December 1, 2012 Share Posted December 1, 2012 Just picked up a new to me 1986 RD688S dump with an E6-350. At idle the truck surges up and down bouncing from 400rpm to about 600rpm..just up and down up and down. Truck runs good and strong...but the idle is hard to get used to...any fixes or known problems that causes this? Quote Link to comment https://www.bigmacktrucks.com/topic/28638-e6-350-idle-surging-problems/ Share on other sites More sharing options...
David Posted December 1, 2012 Share Posted December 1, 2012 Idle should be set higher than 400. Hows the oil pressure? Quote Link to comment https://www.bigmacktrucks.com/topic/28638-e6-350-idle-surging-problems/#findComment-148933 Share on other sites More sharing options...
Vladislav Posted December 1, 2012 Share Posted December 1, 2012 I have the same issue in my R688 E6-350.It makes that way when it's cold.I suppose there's a governor in the injection pump, haven't made research yet. Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/28638-e6-350-idle-surging-problems/#findComment-148937 Share on other sites More sharing options...
turckster Posted December 2, 2012 Share Posted December 2, 2012 Most likely the problem is in the injection pump's governor, bushings worn out on the flyweights or something like that, If memory serves me correct, I think the governor housing can be removed and repaired on the bench. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/28638-e6-350-idle-surging-problems/#findComment-149065 Share on other sites More sharing options...
krismoriah Posted December 2, 2012 Author Share Posted December 2, 2012 oil pressure is good 60lbs at idle. Truck is very difficult to start..so i was relating the surging to maybe sucking air as it runs...which also makes it lose its prime... but perhaps the governor is at fault for this too? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/28638-e6-350-idle-surging-problems/#findComment-149075 Share on other sites More sharing options...
Vladislav Posted December 2, 2012 Share Posted December 2, 2012 Air income into fuel can make any issues including idle. It realises as bad engine work, governor may trying to keep revs so the play gets.You noted first that the truck runs strong, I don't think she can do it with air in fuel. Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/28638-e6-350-idle-surging-problems/#findComment-149077 Share on other sites More sharing options...
Kav Posted December 6, 2012 Share Posted December 6, 2012 Hi Krismoriah, Try putting the front wheels of the truck in a gutter or hole to make it slope down in front while it is running. If the surging stops or changes it usually means that the Weights in the governor have worn bushes or are loose. You can just slip the governor housing off and check it. It is a good idea to change the bearings in the Governor at the same time and fit new gasgets. It dosen't cost much to do this. Regards - Michael. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/28638-e6-350-idle-surging-problems/#findComment-149674 Share on other sites More sharing options...
Full Floater Posted August 28, 2015 Share Posted August 28, 2015 Mine even does it when im steady on the throttle. Kind of annoying Quote Link to comment https://www.bigmacktrucks.com/topic/28638-e6-350-idle-surging-problems/#findComment-301781 Share on other sites More sharing options...
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