Guys,
Just pressure tested the old girl and all is fine on that front so I am thinking spark plugs or coils.
I take it the coils on the standard XJ6 are the same as on the XJR?
First port of call will be the sparks, but I want to make sure I am ready for the expensive option!

On another note, would running with the rear lamda(o2) sensor disconnected cause any problems? Going to replace it, I just want to make sure its not the cause of all my problems?!

Many Thanks

Mat

 

do you have a lumpy idle or a constant misfire? do you get a check engine light? any fault codes? The rear o2 sensor, the downstream sensor is the one that actually adjusts the fueling instead of the upstream sensor like in most cars. So yes, being unhooked will cause running issues

 

Its a constant misfire and a bad one at that. Its got to be more than one cylinder, it rattles the exhaust just about off its mountings!
I do get a check engine light but have not had a chance to get the fault codes read yet. Im going to see if I can reconnect the lambda sensor as the only thing wrong with it is the cable was torn off as it was removed from its shipping container. See if it makes any difference.

Thanks for the info, its much appreciated.

 

Yes, the same


Cheers
DD

 

You really *should* get the codes before proceeding, of course. basic code readers are cheap these days. Or for just $150 or so...maybe even less....you can get a basic, DIY-grade scan tool that shows a live data stream of sensor readings. I use an Innova 3130. it covers all the basics.

One trick is to remove the coil cover and run the engine in the dark. If you see 'sparking' in the opaque potting compound at the top of a coil, that coil is a dud. Sometimes this is accompanied by crazy dashboard antics: wild swinging of the gauges needles and a Tokyo-at-night warning light displays.

Note, though, that *lack* is visible sparking doesn't prove that the coil is good.

With an ohm meter you can check primary resistance of each coil. It should be .75 ohm.

Cheers
DD

 

Quick Update guys,
After replacing all the coils and spark plugs and having the injectors cleaned and serviced it dawned on me that the guys that had imported it from Japan for me had put the spark cables in the wrong sequence causing it to misfire. A quick swap around of the two rear cylinders and she fires on all six. Its always the simplest things that you miss!!

She still runs rough, but I am pretty sure that is down to the torn off o2 sensor. I should be getting replaced this afternoon if they have the part in stock.

One step closer to getting a set of plates and a big grin on my face!

 

That's exactly the same thing that happened to mine when I did the cam cover gasket, glad you got it figured out.

 

Doesn't the rearmost coil wiring have a marker on it to aid identification?

 

Not that im aware of but I did consider numbering them for some future owner as this issue has happened to a few people now. Also, why would they unhook the coils to import it?

 

Mine does, I just didnt notice it until I had replaced most of the ignition system!!

They said they had problems getting it started to drive out of the container, so pulled the leads off to check the spark plugs.