Jaguar XJ8 and XJR8 (1997 - 2003) - 01 3.2 Very Rough on Idling | Technical matters | Back Room Forum

Mon 24 Aug 2009 19:48

01 3.2 Very Rough on Idling - Pole2934

Jaguar XJ8 3.2 Sports 2001 Y plate 114k miles

Regularly serviced as per book. Only mishap was a year ago when warning light indicated left hand side oxygen sensor fault. Reset and never appeared again. Car runs perfect and has bags of power and sounds sweet in every way until ?..

The Problem.

Car left on drive in rain for maybe 4 days. Started up perfectly on first turn and I drove off. About 60 yds along road engine warning light began to flash and then ?Reduced Power ? warning appeared. I turned around and got onto drive . I was about to shut off engine and engine warning light stopped flashing and Reduced Power warning disappeared. Engine sounded Ok on throttle, but very rough on idling so much that it shook the car violently. Stopped and left car on drive to ring my trusted garage.

On advice, I tried car once more the next day. Same as before in that warning light flashing and Reduced Power warning on dashboard. On a bit of throttle sounded Ok , but on idle very rough.

Carefully drove 5 miles to mechanics garage and on journey car sounded fine above 1,000 revs but rough on idle.

Tests at garage were as follows

Completed OBD2 reading which showed codes P301 and P302 and another code which I forgot but meant multiple misfire.

- Changed plugs?. No difference

- Bought Jaguar Coil and tried each cylinder one by one with new coil. No difference

- Tried compression testing and ALL cylinders same reading of 225. Assumed this was good news?

- Inlet manifold seals checked and all OK.

- All hoses checked and all OK.

- All injectors checked and spraying fine.

- As before runs well above 1,000 revs? But rough , very rough on idle.

Need any help suggestions?

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Tue 25 Aug 2009 00:22

01 3.2 Very Rough on Idling - Kevin

I know this sounds silly but check your alternator/battery voltage.

The Jaguar ECUs are very fussy about input voltage.

Kevin...

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Tue 25 Aug 2009 01:33

01 3.2 Very Rough on Idling - Pole2934

Thanks Kevin. I will get it tested and let you know.

Pole2934

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Wed 26 Aug 2009 00:23

01 3.2 Very Rough on Idling - davecuk

I thought the injectors were problematic on the Jags....might be worth checking them again.

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Tue 1 Mar 2011 19:02

01 3.2 Very Rough on Idling - SirJag

Hello Pole2934...Did you ever resolve this rough idle issue with your Jag? I just bought one and am having the same isssue... especially when it's put in reverse. (Same way for you?) What did you eventually discover that fixed it?

Thank you! SirJag

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Wed 2 Mar 2011 10:34

01 3.2 Very Rough on Idling - injection doc

are the timming chains ok ? they do suffer with the guides breaking causing rough idle and eventually snap !

It does sound more like ignition but would check condition of the chains !

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Wed 2 Mar 2011 22:26

01 3.2 Very Rough on Idling - SteveLee

are the timming chains ok ? they do suffer with the guides breaking causing rough idle and eventually snap !

It does sound more like ignition but would check condition of the chains !

Hi Doc, the original post was for a 2001 car, I believe the dodgy plastic cam-chain tensioners were replaced with metal ones half way through 2000. Steve.

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Thu 3 Mar 2011 10:57

01 3.2 Very Rough on Idling - injection doc

Hi SteveLee, yeah they were upgraded but seen plenty break, but i guess we will never know as its an old post. i always just err on the side of caution so its one of the first things I would check if I was working on it. Nothing worse than have a car in to fix and be reving it to check for a misfire and have a chain snap ! LOL

Rgds ID

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