Hello and good morning. I have finally taken the jump into the reviving of a 2000 XK8 Convertible and let me tell you, she's going down kicking and screaming. I have a 2000 XK8 with 118k on it. Make a long story short, the motor blew and I went in search of a replacement. Found a 54k motor out of a 99 XK8 same 8th letter digit on the VIN (C=A27). Install was good. Al sensors hooked up. Put in a new battery because the one I had in there died. Found this out when I tried to start the car after the motor install. Dash lights came on, turned the key, crank, but no start. I replaced the Cam Positon sensor, no luck. Check for fuel, it's getting fuel. Checked for 12v at the coils, it's getting it. I tried disconnecting the battery overnight, no luck. I read it may be the immobilizer, but they said to hard start the ECU. I will try that tonight. In other words, I am stumped!! Please help me as I love this car and want to drive it!

 

Have you pressed the inertia switch? That may indeed be worth a try....

 

Since I am more of an antique American Car guy, forgive when I ask where is and what is the inertia switch?

 

My guess would be that since you have a 1999 ECU trying to communicate with a 2000 throttle body the software isn't compatible. I would recommend matching the throttle body to the ECU. The inertia switch is located in the fuse box in front of the facia.

 

I was told that the throttle body is the same from 99-2002. Everything hooked up real well. Maybe I will try switching it out.

 

You say it's getting fuel, but what is the pressure at the fuel rail? I suspect the injectors are not firing if you do have 40 psi fuel pressure. Then again, if the injectors are working you may be suffering from bore wash from repeatedly trying to start.

You replaced the cam sensor, but what about the crank sensor? Is it connected?

 

Yes. Both crank sensors were replaced and I tripple
checkrd all connections. They are all plugged in.

 

Check compression- if all around 30-60 psi you may have bore wash. Easy fix- just a teaspoon of oil down each cylinder and you should be good to go after some cranking.

 

OK.....after doing a hard start on ECU and filling the tank up with two more gallons of premium I took two stabs at the throttle and the car fired right up. Now, the bad part is she runs rough and dies. I rev the gas and she rough real rough and when I let go of gas she dies. I have replace the fuel filter. but I am stumped. Any ideas?

 

You have 2 fuses for the fuel one on start and the other for run. This link chould help.

Link JagRepair.com - Jaguar Repair Information Resource

 

It sounds like you are getting fuel just not all of the cylinders are firing. I had something similar when I did my timing chain, I rushed to get it back up and didnt clip the injector connectors back on one bank. She fired but very lumpy on tickover and would stall, it would run a bit better with some throttle. Check your injector connections just to make sure. Maybe run the fuel pump for a time to clear any airlocks in the fuel line? Check your fuel trims, if it was injector related or even coils not giving a spark then you will have high positive fuel trims. You could replace the coils or injectors (easier to replace the inlet manifold) with the ones from the original engine. Cant really think of anything else without it being in front of me

 

I am posting a completely useless post, just thought I would say I am rooting for you!

 

I would now hard reset the battery, then start it without pressing the gas at all. may take a few tries, they like to start, rev up then settle down. If still no joy, start looking a all your connections (good advice on the injector plugs) and any place air can enter into the equation (brake boost, part load breather, full load breather)

 

Low and behold she fired up and purrs like the cat she should!!! I changed the fuel pressure regulator, LH knock sensor and there was a plastic tube that was disconnected that goes under the throttle body into the manifold on the passanger side. Cleaned out the throttle body with injector cleaner and she fire right up. ran for 90 minutes without throwing a code at all. Talk about chasing gremlins. Thanks all for the input!!!!!

 

This should be a lesson to all of us to ask for the codes before making suggestions.