Finding an air leak - Easy Start ?

[Dodsy]

My XJR is showing high Lambda correction readings so I think there is an air leak somewhere. As expected the Jag Dealer said 'nothing wrong' despite the lambdas showing 10% and higher correction readings. So Its down to me to see if I can find the leak.

In my youth I would just squirt some easy start on gaskets and joins in the inlet pipework , the engine would rev up a bit and presto, leak found. Is this still ok to do with a modern engine ? the XJR is a supercharged V8 if that makes a difference,

[Turkey]

Can't see what could be too sensitive to a small amount of easy start in this manner.

If the revs start rising due to the easy start being sucked in, then the ECU MIGHT (not guaranteed by a long shot imho) put the EML light on..

Other than that, the MAF sensor if fitted could be damaged by a coating in a solvent, these run heated wires so it could ignite the easy start, possibly, or overheat and damage the element. If you have another type of air inlet sensor such as a hot film I would check the risk of damage to those too. These are only risks, if you are gentle with the easy start it probably won't cause any harm at all, you aren't spraying it directly into the inlet after all.

I can't think of anything else that could be affected by a small dose of easy start.

HTH

[Turkey]

ETA, being a 2007 model any cheap OBDII reader should be able to read and clear the fault codes, they might even be capable of showing fuelling data too. It was mandatory that mass produced petrol cars made after sometime around 2001 were OBDII/EOBD compliant so any cheap code reader could talk to them (Diesels were around 2004+ for info.). An ODBII reader could be a wise investment if you don't have one already.

[Steffan]

I would suggest a Jag specialist non dealer garage first. They might have suggestions and might be actually interested as opposed to going through the motions for a fee. Specialists of this sort to seem to offer a better bet with serious classics IMO. Up to the OP.

[Mave]

Do you know if the lambda is wrong at idle or under load? Under load the MAF and intake manifold will all be under pressure rather than vacuum, so any leak would cause it to run rich rather than lean. Might be worth checking the exhaust as well as the intake.

[Dodsy]

Thanks for all the replies, a little more info on this...

I have an OBDII reader wirelessly connected to my iphone , thats how I am reading the lambdas. I have today bought an in car mount so I can see what its doing while driving, so far I've only tested it on my drive.

The exhaust is showing bang on readings as it should (its been tested twice) , but then I assume that means the lambda corrections are doing their job properly and keeping the mixture right.

I agree about the specialist garage, I know of one but its finding the time to get there (50 miles away). Once I've had a few runs with the live OBD readings that might be a better bet than just squirting easy start all over the place.

[Goldenb19]

Hey fella Iv used a blow torch and some fuel pipe in the past on my Veccy remove the end off the blow torch add the fuel pipe to the end start the car turn on the gas And move the pipe around the gaskets and when near an air leak the engine will rev it's a bit safer than easy start or carb cleaner as they can catch fire in the bay

[Goldenb19]

Hey fella Iv used a blow torch and some fuel pipe in the past on my Veccy remove the end off the blow torch add the fuel pipe to the end start the car turn on the gas And move the pipe around the gaskets and when near an air leak the engine will rev it's a bit safer than easy start or carb cleaner as they can catch fire in the bay

[Dodsy]

Goldenb19 said:

Hey fella Iv used a blow torch and some fuel pipe in the past on my Veccy remove the end off the blow torch add the fuel pipe to the end start the car turn on the gas And move the pipe around the gaskets and when near an air leak the engine will rev it's a bit safer than easy start or carb cleaner as they can catch fire in the bay

Ah I like that idea. I feel a plan coming on

[Rich1973]

Have you asked on www.jaguarforum.co.uk?
Friendly site and lots of knowledgable people on there.
Nice car BTW. I used to have a X308 XJR