Hi all,

Im a bit stumped, I have a 2001 XK8 that was sitting in the garage for a while. Battery fully charged, the car starts, will run for a second or 2 then cut out. It does this very consistently, almost like a anti-theft cutout? I checked fuel pressure at the rail, getting 40PSI. Battery is fully charged. I have a check engine light, pulled codes with my Launch Mini Pro scanner, getting misfire codes on all cylinders. Can anyone throw me a bone on this one?

Thanks!

 

The misfires are likely due to a lean condition because it is not getting enough fuel or bad mixture. Extreme vacuume leak maybe? I experienced a similar problem with my 2002 XK8 that was a rescue. Are you getting any other codes?

 

How old is the fuel in the tank?

 

This started a few months ago, the car is actually my neighbors. He took the car out for a drive, got a few blocks away and the car died. After checking around, he found the aftermarket battery disconnect switch he installed was overheated on the negative terminal. We let the car cool off and connected ground strap directly to the battery. It hasnt started since. My scan tool is accessing the ECU but Im wondering now if thats no good any longer?

 

I think you are on the right path. If the ECU is still operating you should be getting some OBD codes on failure. I would think you can get a used ECU and give that a try.

 

I'll see if I can find an ebay ECU with corresponding numbers. Ive read some posts in regarding to recode the new ecu to the vehicle. Do you where I can find some informtaion on this procedure? I have to check if my Mini Pro scanner has the security function. Thanks!

 

Check the fuel pressure at the schrader valve on the fuel rail, should give a good spurt with the ignition on. The pump may be failing.

 

That was my initial thought but Im getting consistent 40 PSI at the rail.

 

Ok, before we go any further, lets answer the question: Why did the battery disconect overheat. Poor design or did it get shorted out some how? The car is obviously gettig fuel and spark with the proper timing, assuming that it is not back fireing.You have decent fuel pressure. If the ecu is missing a signal or getting bad information, you will likely get a code other than "both banks running lean". I was recently testing a throttle body on my car to verify that it was good. I thought I had the partial load crank vent installed good enough but it wasn't (hose under and on the left side of throttle body) I got the same reaction as you. Start, stall. The plastic corregated hoses dry and crack over time. I would suggest you start there, also there is a large hose that enters from the rear of the throttle body that could be source for a leak. I have never DIY'ed a smoke system for checking the intake for leaks but I would suggest hitting the YouTubes for info on that.

 

YOU CANNOT SWAP ECMs WITHOUT PERFORMING AN 'IMMOBILIZATION-SETUP'!

The modules on the CAN bus need to be 'introduced' to the replacement ECM and it must have a matching VCATS.

Perform a search for the term IMMOBILIZATION-SETUP for the X100 or X308 4.0 engine Jaguars.
It is a simple procedure but requires SPECIFIC software/hardware.

 

My first thought when I read your post was 'fuel pump', particularly as the car has stood for some time. These things tend to die in their sleep, so I'm with RJ.

ECM could be a problem, but it wouldn't be at the top of my list. First would be fuel filter behind LHS wheel. A partially-blocked filter might give you reasonable pressure on a check, but the fuel flow rate wil be reduced.

Coupe or convertible?