Help,Help,Help, Had most all I can take.
 

I backed the car off the ramps and within 10 seconds motor bogs down and smoke starts boiling out between firewall and motor,(smells like rubber burning) center little more to passenger. I have not touched anything back there WTH is going on ?

I went back out after smoked stopped. Thought it might be tranny so I left it in park,started it and motor is bogged down RPM is usually at 9,000 now about 4,000. Tried to rev motor and was like trying to drive with brake on.
Turned it off,waited a little while, put in neutral and same thing. Did not let run long enough for smoke to start. Has plenty oil,water. Was stone cold before starting and with in 10 seconds this happened.

I looked under car when it was smoking and could see smoke coming down around passenger catalytic converter. Oil pressure is good at 50.
Think a spun rear crank bearing,hope I'm wrong as I will part out or sell cheap.

macdoesit,

is it running on 12 or 6 cylinders? Smoke coming off 1 cat, idling badly at 400 and not wanting to rev sounds like it could be running on 6. Usual Marelli problem, perhaps?

Paul

The motor is not running rough, where is all the rubber smell smoke coming from ?
Does the marelli just go all the sudden ?

Thank you for help.

Before this goes any further, do yourself a favor and remove the P/S air filter. Is it wet with oil by chance? I know you said it had plenty of oil in it but, a little does go a long way when it comes to oil on hot components. Since you had it up on ramps, maybe some oil got on the exhaust and is making it smoke so much??

I will take the breather off and check, I put new ones in last week.
Had on off ramps a lot past week no smoke.
Smells like rubber and engine has a lot of resistance, like giving it gas with emergency brake on.

With a Marelli failure one bank goes kaput but the engine doesn't get rough. Low power is the main symptom, followed very quickly by an overheating converter....sometimes to the point of glowing cherry red.


Might be some oil on the converter. Or the converter is getting hot enough to overheat anything close by. Sometimes to the point of starting a fire.


Yup.

Backtrack over your recent work and see if you've knocked some wiring loose or the like. If all that looks Ok pull the distributor cap and check the rotor.

If one bank is dead you can also try swapping modules (above the radiator) and coils to see if the problem goes to the other bank

Cheers
DD

Thanks Doug and Ptjs1.
So I need a new cap and rotor ?
Glad to hear not real serious. I will check into it tomorrow.

Maybe, maybe not. inspect them before buying.

Also check associated wiring and check/swap control modules

Cheers
DD

The units on the cross member are rarely dead. The Marelli system is more so either coil or rotor/cap.

Well, I think you can rule out a spun rear main bearing. I've never seen or heard one "go up in smoke". Leak, yes. But for the "gushing oil to get past the housing and under pan on to a cat would be rare indeed.


The thought occurs that a cam cover gasket could be leaking and that oil is getting on an exhaust pipe or even a cat.


That goes for the smoke.


But, as to the rough running, it means go to the diagnostics suggested above.


Carl

My bet is the oil melted down the catalytic converter and plugged it. The cats will get so hot it will start to cook stuff around it like rubber parts and body coatings. The restricted cat will restrict air flow through the cylinders.

I don't understand " oil melted down the catalytic converter and plugged it"

Not "rough running" Car cannot be driven in present condition.

If swapping modules and problem goes to other bank, then it is a bad module???

When you guys say "merilli" I assume you are talking "distributor cap and rotor" How does a distributor cap/rotor kill one bank 6 cylinders and not effect the other bank ?

It uses a stepped double-ended rotor arm and a matched distributor cap. One end of the rotor arm is firing Bank A cylinders and the other end is firing Bank B cylinders.

So the failure of the rotor arm insulation causes 6 cylinders not to get sparks, hence one bank is out. You're then dumping fuel straight out the exhaust on that side with the subsequent heating up of the cat.

Hope that helps.

Paul

Mac, you really should download and read the Great Palm's XJS maintenance book from Jaglovers. It is free and will very clearly explain all these and all other matters.

Thank you

Thanks, If I find it, I will down load it and post it here so others can download.

http://www.jag-lovers.org/xj-s/book/Jaguar.html

Correctly the ignition system is from Magneti Marelli, an Italian electronics and automotive producer with a roughly 'just as good' reputation as Lucas does (Prince of Darkness, inventor of the short circuit, ...). The ignition is a very complex setup, have been reading up on it and it uses/utilises more sensors and equipment than the EFI does, but works mostly reliable.

Due to the construction limits, it basically is two 6 cylinder distributors in one. Effectively turning the V12 into two I6 engines cast together. In theory it would be able to use cylinder deactivation (like modern V8, V12 and some I4 and even I3 engines) and run on one bank when cruising (it would actually be a rather easy implementation).