I purchased a 1999 XK8 in May, have had no problems until yester (replaced MAF sensor in June). Driving home and suddenly car lost power, idled rough and stalled. Had it towed home, let it sit for about 2 hours and it started up, ran 30 seconds just fine and stalled again. Did the same thing this am. I appear to be getting fuel at the rail, have checked air flow, even put the old MAF sensor in. Car seems to star every 2 hours for about 30 seconds. Runs fine then idle drops, no power and stalls. I'm thinking it isn't the fuel day (I can hear it prime), I'm getting spark, or it wouldn't start every 2 hours. I've checked all fuses, wiring harnesses, and no computer codes... Any ideas what I can check?

 

Removed the ECU (with battery disconnected), open up the case and inspect the circuit board for leaking electrolytic capacitors. Signs include moisture, brown or black spots and corrosion spots.

ECUs usually can be professionally rebuilt.

 

Thanks, just pulled it out. It looks clean and ok.

 

Have you checked or ever changed fuel filter. It might be letting enough by to get it started but not enough to keep it running.

 

ECM looks clean, both sides, no evidence of leaking or corrosion

 

Fuel filter was replaced 11/14, along with fuel pump. I've been getting 19mpg up until now mostly driving in heavy traffic, would it fail instantly?

 

I believe you have a fuel pressure regulator, while the pump would provide fuel to the rail the regulator has been know to go bad.

 

Have you checked the long term fuel trims?

I had a similar stalling problem when the trims were maxed out and still wanted more adjustment than the ECU could give.

It was a funny thing, because a hard reset would make it run fine until the adaptations maxed out and then the stalling while driving started. Similar behavior at idle too, start it up and would be fine until it went into full closed loop mode, then stall.

If the trims are way high, start checking for an air leak somewhere.

 

Try reading your OBDII codes and see what you come up with.

Gus
www.jagrepair.com

 

Mine did that before I had the PCM looked out and deemed needed rebuilt, all that after 3 TB's were put on it thinking that was the issue the indy said. I was like, OK, this is the 3rd TB, still doing it, I know the PCM could be an issue, told them to get my orig TB back, put it on, got PCM back, car has been running fine since.

 

No codes P1000 (disconnected battery), I changed the fuel filter because it was easy, interesting, now not seeing fuel in the valve on the rail. I've ordered a new fuel pump (looks like a shitty job). Car will start and run for a few if I spray starter fluid into the intake. Really looks to be the fuel pump now... Will keep you posted!

 

Let me be the first to tell you NOT to use starter fluid it can cause you to crack the intake manifold. It is plastic! Use this link and check the power to the pump it has 2 fuses and one relay.

Link JagRepair.com - Jaguar Repair Information Resource

Link JagRepair.com - Jaguar Repair Information Resource

 

Thanks for the help, it was the fuel pump which i've just replaced and cat is running sweet now

 

Great!