Oil in Air Intake
 

XJR6 X300 1996.
Have found oil in air intake from supercharger to intercooler. Supercharger gearbox oil is full, so where could it be coming from? Car is overfuelling to a chronic degree, spark plugs coated with soot to the extent of spark plugs not operating properly. Cleaned spark plugs and found same thing within 5 to 10 kms. Help please! Urgent.

cylinder compression low from piston ring seal overcoming air / oil separator ?

The blowby oil interferes with the engine regulation sensors including the O2 sensors

The cylinder compression should be something like 115 PSI at 300 RPM starter speed

But that is a factory new specification from Jaguar I once seen someone gave me

Thank you

Dave, if you are reaching the end of your tether, Mark Yates off Watchman Rd in Napier should be able to sort it for you. He has had plenty of practice on my XJR6! And knows his stuff

Thanks for the info

Dave,

I would first check your engine oil level is not way overfilled and then check the crankcase breather hose is not excessively oily. I presume there is a pcv installed in the breather hose on a XJR that should be reasonably clean and clear.

It sounds like this problem is new and has not previously been experienced. Have you or your mechanic made any recent changes to the engine? I ask as I have in the past installed a new cam cover gasket in another engine that didn't have the cut out for the breather hose!

I had overfuelling issues that was sorted out by replacing a TPS that bench tested perfectly fine.

This happened after I:
1. Replaced oxygen sensors
2. Replaced maf
3. Replaced coolant temp sensor
4. Replaced coils with Made In Japan labeled Diamond coils
5. Had injectors professionally cleaned
6. Replaced fuel pressure regulator
7. Replaced camshaft position sensor
8. Replaced crankshaft position sensor
9. Replaced cracked exhaust manifolds
10. Replaced EGR
11. Replaced IACV

And probably a few other items....

If I were to do it again, I’d start at the TPS....it’s a pricey item, but when it goes, apparently there’s no easy way to test it.

As for the oil in the air intake....it’s normal. I ended up installing an oil catch can in my engine bay.

Actually, I should clarify, some oil in the intake is normal? It’ll require you to clean your throttle body because it eventually gets gummed up.

The catch can seems to minimize, but not completely eliminate all oil. I have a very long run of hose connecting the oil catch can mounted just behind the passengers headlights. I thought that would eliminate it 100%, but trace amounts still go through.....

I wasn’t cleaning out the can nearly enough, and have been much better about that now. We’ll see what happens.

Thank you

Thank you.

I think I may have to replace TPS. Would you happen to have a part number for this and where I could purchase one.
Much obliged

Before you go through that expense, have you checked the oxygen sensors for your car? That could cause your condition as well.

Are you able to pull data from your OBD2 port? I'd love to see the oxygen sensor data after the car has been warmed up.

As for the part number, JLM12074 is for the NA 4.0 AJ16 engine, but since yours is supercharged, you may require a different one. I would shop and purchase this part from JDHT.

I assume you have no check engine light or codes?