I picked up a 2003 XK8 on Monday. The DSC/ABS indicators came on a couple of days later. I think I know how to resolve that, I'm going to clean the wheel speed sensors this weekend. However there are two other things I'm not too sure about:

1) When I start the car when it is cold it seems to crank for 5-8 seconds before it finally fires up and starts to run. It was kinda scary the first time because I didn't think it was going to start. When it's warm it starts right up no problem, it's only slow to start when it's cold. (And when I say cold, it's been in the 80's here, so it's not like it's cold cold. It's just that the engine isn't warm.)

2) Sometimes the display for the nav system doesn't come on. I see it flicker briefly when I turn the key, but then the display is blank. This isn't really a big deal since the maps are antiques, but still, it would be nice if it worked all of the time consistently.

Does anyone have an idea of what could be causing these problems?

 

hmmm, same car here, and never more than a 1-2 second firing sequence. I wonder if your fuel filter is jammed up, what about the air filter, check it out?

There's a DIY instruction on checking and cleaning the MAFS if you want to look there too.

as for the Nav, I've had some issues with it not 'displaying' correctly, meaning blank screen. It only happens when I don't pause long enough between turns of the key. The long start could also be affecting the time it takes to 're-boot' from the point of ignition on, to actually running. Work on your start problem first, then see if the NAV was just related electrically via software.

 

AH! You may have solved the nav system problem. Today when it occurred I had turned the car off very briefly to get the ABS light to go out. I'm not sure what happened the other time, but maybe it was the same thing. I'll just remember to leave the ignition off for a longer interval before restarting next time to see what happens.

In regards to the slow start, I was thinking along the lines of the fuel system, too. I was thinking that it was possibly an issue with the fuel pump not building up pressure quickly enough. I supposed a dirty fuel filter could cause a similar problem. Tomorrow morning when I start it I'm going to turn on the key for 10-12 seconds before I try to crank it. If it starts fine I'll have a pretty good idea that it has to do with the fuel pump or filter. Of course, I'm assuming that the fuel pump starts turning as soon as the key is turned to the "on" position. I believe that's the way it works on most cars.

 

My 03 had the same problem last fall. The dealer cleaned the front wheel sensors. He also removed the ABS connector and cleaned the pin contacts. This worked (?) for a month and then the DSC light started coming on again intermittently. This time he got code B2736 and replaced the pedal travel sensor. He also found a TSB on this problem, so it must be quite common. I have not had any problem since then.

 

Hey Rev-
Starting issue could be fuel system not holding pressure after sitting awhile. There is a check valve in the fuel pump that holds pressure in the line and fuel rail. This could be weak and allowing pressure bleed down, or possibly a leaking injector allowing bleed down. When you turn the key to "on" the pump will run for 2 secs or so to prime the system and when you crank/start the car the pump will run. I don't know your skill set but this can be easily verified with a pressure gauge.

John

 

After sitting at least overnight, my car takes longer to start also. But since it only takes 3-4 seconds instead of immediately, I don't see any cause to be concerned.

 

This morning I turned the key on and let it sit in the "run" position for about ten seconds before trying to crank it. It didn't make any difference. It still took about 5 seconds before it started. So if Beauregard is correct about the pump running for 2 seconds when I turn the key to the "on" position, then if I turn the key to on, then turn it back off, then repeat that sequence three or four times, the pressure should have built up enough so that when I finally crank it it should start right up. I think I'll try that tomorrow. It sounds exactly like it's the leaky check valve or a leaky injector. I think I can live with the problem because neither sound very easy to fix.

 

Aha! I now know why the car is slow to start thanks to Beauregard. This morning I stuck the key in and turned it to the "run" position for two seconds. Then I turned it off and back to "run" for another two seconds. I did that 4 times before I cranked it. When I cranked it it started right up. Apparently the pressure in the fuel system is leaking down over night. The two second run of the fuel pump to prime the system isn't enough. By turning the key off and on several times I gave it enough pressure to start up right away. Apparently this is just a minor annoyance and not anything that will cause major problems. I can live with it, especially since I know how to work around it now.

 

That exact symptom is the last repair I ended up making on my Corvette just before it finally sold. This one really stumped the independent Corvette guy I had been using for almost 15 years since the ONLY problem that showed up was difficulty in starting the car. Once it was started it ran fine under all conditions. When I was trying to track down the problem myself, I hooked up a pressure gauge to the schrader valve on the fuel rail and noticed the pressure would drop immediately upon turning off the engine. Similarly, when I turned the key on (but without actually cranking) the pump would prime for a few seconds and the pressure would build up but immediately drop. These types of symptoms are usually indicative of a faulty fuel pressure regulator and the mechanic stubbornly refused to believe it was the fuel pump. However, after trying everything else he replace the fuel pump and problem solved. The mechanic said that I would eventually have had problems while driving so it was lucky we changed the pump. Of course that was with the Corvette but I am sure the fuel delivery system is not much different for the Jaguar.

Doug

 

So SeismicGuy, are you saying that I need to change my fuel pump to prevent future problems? My wife and I are planning a 6000 mile road trip this summer. I'd hate for the fuel pump to give out somewhere in western New Mexico. It would probably take a week to get a replacement and that would pretty much ruin the trip.

 

Hey Rev/Sam--

What I am saying is that the two times I had problems with the fuel pump in my Corvette, one time there was no warning at all. That first time I had been driving around find doing errands one day. When I tried starting again after one of my stops, the car would not start. I knew it was the fuel pump since I did not hear the telltale sound of the pump "priming" when I turned the key. Prior to that there was absolutely NO warning. I had to have the car flatbedded to my mechanic.

The next time was just over a year later when the warning signs were the difficulty in starting the car. The reasons that the mechanic had not initially suspected the fuel pump was that (1) he had replaced the pump just over a year before and (2) the more "typical" symptoms of a failing pump are bogs and surges while driving.

I think the Jaguars have 2 pumps but I am not sure if the purpose is so that one can back up the other. So I would suggest addressing your problem so you don't end up getting stranded somewhere without warning.

Doug

 

The XKR has two pumps and will run on one. The XK8 only has one and will not run without it. Check the fuel pressure at the valve on the fuel rail. 41psi +-.

There is a fuel pressure regulator and fuel filter to consider also.