Update - rough idle on XJ - AUSJEEPOFFROAD.COM Jeep News Australia and New Zealand

Kramer · #1 23-08-2002

OK.

Disco'd the injector leads one at a time and found that no. 1 cylinder did the least when not injected.

Swapped injectors 1 and 2 over, restarted and found that the problem was still with cylinder 1 as before, no change at all.

Can't get back to this now till the arvo, but next I will sheck the manifold bolts for tightness around the inlet of 1 and between 1 and 2.

Then I will spend some time on the leads. Will pull out the plug on 1 as well and try to get a pressure gauge from somewhere to check compression.

[ 24 August 2002, 12:11 PM: Message edited by: Kramer ]

Kramer · #2 24-08-2002

The spark plugs are only 300 km old.

Number 1 is darker than all the others. A sort of browny-tan colour on both the ceramic around the electrode and the earth tip.

All the others are the same colour - white ceramic and light grey earth tip.

Plugs are the correct ones for the car. Brand is NGK.

Couldn't measure compression because the thread on the brass fitting on the end of the compression test hose was too short - need an extention fitting, might have to find a universal bolt joint or talk to a gasfitter somewhere.

Are the lifters hydraulic? Or adjustable. Maybe the valve doesn't close properly because of lifter adjustment?

Kramer.

dxj · #3 25-08-2002

HI,

Can't remember what colours mean, there are charts around for this somewhere.

Did you swap plugs/leads from cyl 1 and 2?

Fault still stay on 1?

I vote for leaky or sticky valve or bad hydraulic lifter/pushrod. Maybe burned valve?

Compression test will tell,

Disclaimer:-
Amateur advice, seek professional help if you are unsure if this applies to you or you aree capable of doing this:-

If you find low compression on 1 compared to others, to eliminate rings as source of lost compression, squirt a very small amount of engine oil ( not much or you will hydro-lock the engine [img]graemlins/crying.gif[/img] ) into the spark plug hole just before you re-test. The oil temporarily seals up sloppy rings. If still low compression it is valves or lifters/push rods.