I am getting a ff36 check engine code. In addition, the engine is running very rough to the point it almost stalls. I am not sure where I should start checking. Any help is appreciated.

 

I just googled it, and found uneven heating on O2 sensor, B bank.

 

Thanks for the help. I'll give it a try and hopefully that will do the trick.

 

If you have a IR thermometer, check the temps on the cat to see if its dead. Hopefully your o2 sensor is just bad. I want to say the rear of the cat should be no more than 150 degrees or so hotter than the front of it. Maybe its getting too much fuel from a bad o2(or other issue) or maybe the cat itself is bad. You can also try to do a quick check between the pipes, if there is a lack of pressure at the pipe with the suspect cat, it could be collapsed.

 

I checked the temp and it is about 150 degrees different. It was running a little rough but it was not very noticeable until it warmed up and the idle dropped and it became more noticable. After it ran for a few minutes I turned it off and it would not restart. The engine turns over and it stutters but won't start.

 

Marelli failure on one bank?

Greg

 

What is the best way to begin checking the marreli system?

 

I applaud you guys for answering the same questions over and over without getting annoyed.

 

Every one of us was a "newbie" at one time. We all remember how it was when we first looked for help with our car.

I still have a lot to learn and many questions to come but I'm more than happy to help the new folks with whatever knowledge I have acquired.

I think appreciation for the XJS is growing so I expect many more new people here in the future.

Welcome to all!!

Mark

 

I appreciate the help. That's what sets this site apart from the others. People are willing to help without belittling others.

 

So I bought a new cap and rotor. I keep seeing things about modifications to make, grinding things down and so forth. Are these things necessary or just in case type of things?

 

If you have the Marelli ignition then you definitely should make the modification. The mod nearly eliminates cat converter fires due to the loss of ignition on the right side of the engine.

Here is a link to how its done;

https://www.jaguarforums.com/forum/x...photos-135024/

Mark