Hello I need help with this one. I’ve got a 1998 that I loaned to a college kid he brought it back to me with a problem where the key turns but most the time it won’t start and won’t turn over. But when it does turn over it starts right up about one and five tries. I had the battery tested as it was new they see it is putting out everything it should be and the voltage is 12.5. I have swapped a couple relays for the starter system and they did not make a difference I have looked at all the connections for any corrosion or anything that is loose and can’t seem to find anything. I tried a second key thinking that the transponder might be failing... but that made no difference. Any suggestions on this one. Thanks Most the time when you turn the key you just hear click click and get the lights in the dash about every fifth time it’ll start up

 

Sounds electrical but check the connectors on the alternator and the starter - try the Ole smack the starter with a hammer and see if that changes the condition - could be allot of things but could be a simple as the starter failing.

Also be aware just looking at it from a standard point, I am no way a specialist on this platform

 

So bulkhead connector for the starter thick wire is tight and not burnt? Same goes with the other end of the cable in the trunk? How about engine earth cable ?

 

Clean the maf sensor and try again
use maf sensor not carb cleaner
Check the air filter too if clean or not

 

Sounds like the starter is going out. When you turn the key in the on position, does the “P” light up red by the J gate? If not, shift it into neutral and see if it cranks over then. Does the “N” light up on the J gate? If you have a thick gauge wire, you can trim the insulation off of both ends and twist it tight resembling a pencil tip. Remove the starter relay again and jump the terminals across from each other with no key in the ignition. One of the 4 terminals is different than the others. Pin 3&5 that’s displayed on the side of the brown relay is what you want to jump in the socket.

 

All good suggestions thank you. I’ve got it up on the lift and the Earth ground going from the body to the bolts on the transmission to motor is a little bit saturated with oil as the valve covers are leaking up above and dripping down I might swap that out with a different one I forgot to mention I have many of these xj8,xjr,xk. So I have lots of spare parts...the car starts every or the key turn..now so it is getting better.. something is going on with a very loud serpentine belt so I will be getting into the front of the motor and get a good look at the connections on the alternator. The connection to the starter is tight but a little bit greasy I’ll get a better look at that in the next day or so too.. thanks for all the suggestions

 

Correction on the last post the car starts every other key turn.." yeah it seems like a demon you turn the key once and it will not start again the key twice and it turns over the starter and fires right up. I switched out the relays and it all my relays are brown. I remember there was something about the blue ones from the original cars

 

Yes the P lights up when The key is turned and when you put it in neutral the N Lights up when it’s in neutral

 

Check the positive battery power STUD on the 'false-bulkhead'.
They get loose and melt causing poor connection.

If that is not the issue, then I would check for a P1260 DTC. (immobilizer key transponder not recognized)

 

I think I am just going to have to live with this problem so far every time it is started sometimes after eight tries. I have been chasing grounds all around this car and electrical connections I thought I had it fixed and so I went out to do a cold start the next morning. It is still got the problem I did not poke hot leads into the relay to jump the starter but now I see a benefit to that... if I can get the starter to turn over 10 times consecutively that would rule out that it was a defective starter. Using that method add six different problems when I got here brake fluid round the passenger wheel it was from the bleeder not tight enough. Then he had a bad idler next to his alternator that had failed broken latches, and the heater air-conditioning control unit has failed just Swapped it with a used one sometimes you just have to wait till it breaks completely.

 

Did you check the power connector at the false bulkhead???

https://www.jaguarforums.com/forum/x...nnector-92454/