RC 4jj1 rough idle - any ideas?

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RC 4jj1 rough idle - any ideas?

Unread post by LagsLux » November 9th, 2017, 10:25 am

RC 3 lt diesel 135k on the clock. At idle the engine is real rough/jumpy. Still runs fine, but gearstick is quite wobbly at the lights. Not noticing any other symptoms really. Anyone have any ideas? All the mounts look OK.

Peter Aawen
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Re: RC 4jj1 rough idle - any ideas?

Unread post by Peter Aawen » November 9th, 2017, 12:34 pm

Have you changed all the filters lately?? Fuel, air, even the oil filter?? Clean fuel, air, & oil are important to running well. And don't forget to pull the fuel inlet & outlet hoses on the injector pump & check/clean any of the tiny little filters that could be hidden under the banjo bolts etc - many I/P's have little gauze metal filters in there that can cause this type of issue as they slowly become clogged over time, running rough at idle because of the restriction, but still running OK once the revs build & delivered fuel pressure increases. Not saying it's gotta be your solution, but it's worth a look anyway! :thumb:
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Re: RC 4jj1 rough idle - any ideas?

Unread post by Hunsta » June 5th, 2018, 6:53 pm

Guess youve probably solved this problem by now. But had the same in my 08 Rado. Although I had 210k on it but mine was lazy injector. Was time for injectors. Fixed to wobble at idle.

Collie Colorado
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Re: RC 4jj1 rough idle - any ideas?

Unread post by Collie Colorado » December 25th, 2018, 9:10 pm

The valve clearances could also need to be done. I got mine done and it was a very noticeable difference. And they weren't over due.

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