Hi,

I'm new to the forum but hoping you guys can point me in the right direction. I have a '97 XK8 coupe with 42,000 miles on it. I recently changed the primary and secondary timing chains and tensioners to the latest upgrade as a precaution. I also changed the alternator at the same time. The engine started up a dream first time. As things warmed up I got some smoke on the passenger side of the engine from under the exhaust manifold area. I couldn't see where it was coming from but I figured maybe I dripped some RTV sealant or something on there and it was burning off. So undeterred, I jumped in and headed out. After about 15 mins of running I stopped at a friends and whilst idling, the engine started mis-firing and the check engine light came on. I switched off and let things cool down. Started up again without the misfire a few minutes later and headed home. By the time I got home (2 miles) it was misfiring again.

Plugging in the OBD scanner produced fault codes related to several of the ignition coils. I don't believe there is anything wrong with the ignition coils but clearly something is causing the system to believe there is. I've also had spurious electrical fault alerts such as rear passenger bulb fail (it hasn't) and passenger door open (it wasn't), In addition, when the headlights are on, turning on the left indicator causes the headlights to go out when they are on dipped beam. Right indicator doesn't demonstrate such foibles! So, now I'm wondering if there is a wiring harness or something down that side of the engine that could have come unclipped and melted the insulation causing these intermittent faults?

To add insult to injury, in addition to all the above, I'm now getting stability control failure (ABS light is off) on top of everything else.

I have a basic understanding of electronics but the vagaries of the CANBUS system and controls which I think this vehicle has are something else.

Any help you can provide in pointing me at other links or suggestions of where to start on diagnosing the root cause would be very much appreciated.

Thank you.

 

One of the most common causes of various electrical faults is a failing battery. Since you changed the alternator that could also be a problem.

Coil failure or misfires are often related to oil in the plug wells, and the oil smoke could be a leaking cam cover gasket. The AJ26 has a special gasket set, one side grey, the other red, and figure 8 seals for the plug wells. You may have used a set for the AJ27 engine, or did you reuse the original?

 

Hi RJ237,
Thanks for the comments. I did also just replace the battery. I also replaced all the seals though I don't recall if there was a colour difference for the cam cover gaskets. They all seemed to fit very well and looked just like the originals. I can check the plug wells tomorrow to see if there is an oil build up problem.

 

Basic rule of car electrics ... If operating one system causes another to go on or off you have an earth fault

 

Did you fully charge your new battery? Sounds alot like low battery voltage to me. Put your battery on a 10 amp charger overnight. Most electrical gremlins in jaguars are battery voltage related. Eliminate this possibility first then move on with electrical diagnosis if necessary.

 

+++1 to what he said. But, at the risk of venturing into a far more technical mantra . . . for any faults that suddenly appear after working on a previously happy Jaguar, always backtrack to find what you have disturbed!

As stated, this could be as simple as a ground connection you have disturbed, or failed to replace. There are other potential causes but symptoms suggest our friend (above) has it nailed. BTW, as a fan of subtle hidden meanings, I love that [Pistnbroke] handle . . . my days of racing and broken pistons are long gone, but I often find myself penniless . . .!

Cheers,
Ken