Hi guys, my 88 XJS starts great when it is first fired up after sitting all night, and runs great, but when it is turned off after the engine is at operating speed after an hour or two it won't start the first try, it behaves almost like it is out of gas or nearly out of gas, and I have to turn the engine over longer for it to start, any ideas on why this is? It is sure annoying, and definitely something is not quite right. If it was a fuel filter it would do it in the morning too but it doesn't, same goes for the fuel pump. ????

 

Hi ,
I am moving your thread off to XJS Forum so you get more answers

 

C'mon guys....help a lady out

 

Hi, thanks, this is Donna, if that pic is of you, you should be a model, you are very pretty.

 

Hi Jetlag

I have similar issues with my '92 V12

I've been playing around with various things related to the fuel system, see this thread :

https://www.jaguarforums.com/forum/s...ad.php?t=31792

Hard starting on the first try can be a number of things, but to further pinpoint the problem, you can do some experiments to narrow down the problem.

Once the car has been left for a few hours (the situation where you are having your hard starting issues) turn the ignition on, but don't crank the car. You should be able to hear the fuel pump running for 2 seconds, and then it stops. If you hear this your fuel pump priming circuit is working. Now turn the ignition off, then on again (let the fuel pump run for its normal 2 seconds), turn the ingition off, then on again (let the fuel pump run for its normal 2 seconds) and as soon as you hear the pump stop running, crank the car.

If it starts first time, then you are losing fuel pressure at the fuel rail. This can be caused by a number of things, but the usual culprit is the check valve has failed. The check valve is supposed to close as soon as the pump stops and hold the fuel pressure, but they frequently jam and stop working. The great news (not) is that the check valve is located in the fuel pump, which is located in the fuel tank. This is a big job to do but you can use the on-off-on-off ignition work around in the mean time.

Another cause can be fuel vapourizing at the rail because of excessive heat build up under the hood. To test for this, park the car somewhere in the shade and cool with the hood open and leave it for a few hours, then go and try to start it. If it starts ok then most likely your fuel is being vapourized. On the later face lighted cars there is a system to increase fuel rail pressure if the fuel is above a certain temperature, but I'm not sure if there is such a system on the older cars. You can try the ignition on-off-on trick for this as it may also help.

The other cause I've seen is due to leaking injectors. The tell tale for this is that once you do get the car started on the 2nd crank, there will be smoke, etc coming out of the exhausts. That one is more difficult to fix, usually requires an injector overhaul.

Try the ignition on-off-on first, and the parking in the shade and report back your findings

 

When I absorb this info I will give it all a try. I normally turn the key to one position which locks the door and leave it there for a second then turn it one more notch and crank the engine. I will try the stuff you mentioned and let you know how it turned out.

 

Good info above, especially the two cycle start procedure before you crank the car.