guys, I think I found my vacuum leak. I ran the car with the hood open. I could hear a slight sucking sound. I think my vacuum leak is on the rear of the driver's side on the gasket between the supercharger hat (supercharger discharge) and the charge coolers. I sprayed a little water out of a spray bottle and it appeared to get sucked up. I probably will try again in the morning to take a look at it in the light. Hopefully this is the only leak....

 

A leak has most effect at light load, such as idle, because otherwise there's so much air coming in the proper way (so, metered by the MAF and vacuum measured by MAP) that the leak is negligible as regards load and the PCM/TCM deciding to shift. There's no vacuum signal from engine to tranny, just a CAN (liken it to the LAN you likely have your PC on) with communications data packets.

But, any leak means the PCM is using false data and that leads to wrong decisions about everything (air/fuel ratio, shifts, everything).

That said, properly working O2 sensors (all 4) will help a lot to compensate. This is a feedback control system

 

Hi guys, I dropped off the car at the shop today and told them what the scan said and what I thought. They said they were going to "smoke it" which I'm guessing is a technique to source leaks. Anyhow hopefully they get it handled!

 

Good tech/diagnosis info. JagV8.

 

Guys, just got off the phone with the shop. They're going to replace the gaskets on the pieces between the supercharger hat and the charge coolers. I'm going to pick the car up monday. Why they didn't use new ones with my recent repairs, I have no clue...

After that I have 2 weeks between when I get back from a work trip and when I leave for Hawaii so maybe I'll sneak in an alcohol injection setup.

 

I just got mine back and I had the same lean codes. They couldn't find any leaks. I don't know what they did for testing. So they decided on a new MAF for my car. As JagV8 suggested mine were at idle as well.

They said they could observe the malfunction while it was running in the shop and when they replaced the MAF it stopped.

I ntitially drove the car for 2 days and 900 miles iand I had zero issues. Then within a few days of bumping around on our "lovely" local roads here I got the codes. We'll see if they've fixed mine or not. I've had similar issues on my 15 year old but under 2000km track car with ECU check lights for the lambda sensors and as annoying as it is they're all spurious. The datalogging shows I'm not running out of range when at extreme loads. That car is pushing almost 400HP out of 2L. So I'm experimenting with some antioxidant treament for the electrical connectors. Apparently if the connectors are of dissimilar metals (plating) you can get some issues on some of the more sensitive sensors. I would think Jaguar is a big enough manufacturere to be well aware of this though.

It's possible that this is not the first attempt to resolve the issue on this car but hunt as I could there were no records of this problem at the the other two Jag dealers that serviced this car before I owned it.

I'm curious to see if the gasket thing fixes your problem in case my problem reappears.

Keep us posted!

Good luck with tracing your issue down!

Bob S.

 

got the car back today. I did a little hard driving but no full throttle runs. It feels and sound healthy again. They replaced the gaskets at a cost of gaskets, $110. They didn't charge me for the labor. They replaced the whole plastic sections with the gaskets attached so maybe that's why they're so expensive. I'll keep you guys posted with updates. I'm going to be commuting 75 miles per day at the end of the week.

 

Good news qwik! Hope it sticks and you can enjoy it for awhile.

Also, of note, I am getting the AE hardware back this week if you want/need it still. Send me a PM if you do.

 

Thanks for the offer on the AE software. I'm debating on whether to buy it or borrow it for a little while. Either way, I know that I'd like to have it when and before I install my alky injection kit in a few weeks. It'll be cool to read the iat2's and see if there is much of a performance gain using the performance analyzer.

I took the car out to lunch today and broke loose a couple times getting up to freeway speeds. I'm back to having fun!