My 1996 Xk8 wont start. Everything electrical on the car works but the starter wont engage , it just clicks. The new fully charged battery is reading just over 13v across the terminals but the voltmeter on the dash shows 9v and the red led is illuminated on the dash voltmeter.
I have checked all fuses under the bonnet and all look okay.
I suspect it could be the voltage regulator on the alternator but dont realy want to start buying parts randomly unless I am fairly sure that is where the fault lies.
I would welcome any info or advice.
Thanks in advance for any replies.

 

Check the looms and connectors for any moisture. If you haven't done so already, check the terminal connections at the battery. If the system is only seeing 9 volts, the vehicle won't start.

 

Welcome to the forum Steve,

I've moved your question from General Tech Help to XK8/XKR forum. This is the place to post technical questions about your model.

Have you checked the cable connections at the High Power Protection Module (see item 5):



These are known to loosen or even start to break up resulting in the symptoms you describe.

Graham

 

Thanks for the responses. I am quite good with the mechanical stuff but electrics on this car seems like a minefield to me

The battery is new and reading 13v. The voltmeter in the car is reading 9v and it wont start, The red light is illuminated on the voltmeter.
The battery connections are good and the leads to the hi power module and fuses near the battery are all good. The starter motor is clicking but I dont think its getting enough V to turn the engine. I have checked every fuse on the car and all are good. Have looked for damage to the loom and none evident.
The Jaguar manual lists a voltage regulator JLM20187 but I cant seem to find this anywhere near the alternator ? ? ? ? I have a picture of it but cant find it on the car. Could it be an issue with the starter or solenoid as everything else on the car works fine but it just wont start ???

Any info much appreciated and thanks in advance.

 

I think the voltage regulator is fixed to the back of the alternator so it doesn't look like a separate part. However, a faulty one can be replaced without the necessity to (and cost of) change the whole alternator.

 

The voltage regulator on the car only falls into place when the alternator is charging so for the moment put that on hold. You say the battery is only providing 13v at the battery after it has been fully charged and if that is the situation I would take it back and have it replaced. As a personal note I recently had a new battery replaced two times because of internal failure.

I would however, check all your connections from the main battery and the High Power Protection Fuses.

Link http://jagrepair.com/images/AutoRepa...AJ27%20N-A.jpg

Link http://jagrepair.com/images/AutoRepa...7PowerDist.jpg

Link http://jagrepair.com/images/AutoRepa...7PowerDist.jpg

 

The connections at the battery and protection module / fuses are all like new. I have checked earths and the loom and cannot find anything. The car still wont start. I admit defeat and have an autoelectrician looking at it on monday.

My obd reader is showing a code P01201 mass or volume air flow A circuit low together with intake air temperature sensor 1 circuit low ??? I dont think these are preventing the car starting and I assumed it was just a 21 year old car spurious sensor issue. Any ideas what the issue is with these codes as i I would like to eliminate them.

Thanks for the replies and also for any info.

Steve.

 

If the starter is not turning the engine over and all the fuses and relays are good then I would say the starter has failed. For all other no start issues see if this information helps.

Link JagRepair.com - Jaguar Repair Information Resource

 

I concur with Gus. More than likely, given the age of vehicle and the number of times the starter gets used, the contacts on the starter solenoid are probably worn. If you are good with mechanical stuff you could probably find the worn parts (a starter rebuild kit) and DIY. If not, a local rebuilder might be able to handle the task if you bring them the starter.

I'd tap on the starter with a mallet and see if the vehicle starts. If it does...voila, you need a starter or at least rebuild it.

Jose

 

First, I'd check the connections in the high power fuse protection box in the spare wheel well - the box that the positive lead from the battery goes straight to, Loose connections here are not unknown and will cause the sort of voltage drop you're experiencing.

It could also be that there is corrosion in the positive battery lead where the battery terminal is crimped on. To check, measure the battery voltage across the actual battery terminals and then compare that with the voltage you next measure across the negative battery terminal and the input terminal of the HP box whose terminals you just checked for tightness. If the two are not almost identical, the problem is in that lead.

 

Check again without pressing the brake pedal. If it does the _exact_ same clicking, it points to your brake switch being faulty. You can then try and gently tap the brake pedal several times to sort of bring a bit of life into the switch, then try again. These switches typically do not fail outright, but become increasingly unreliable over time, to a point.

Best of luck, keep us posted.

 

Thanks for all the replies. I am making progress " slowly

I have been through all of the checks detailed on here and have no success.
Everything points to a failed starter motor and I now have a new denso replacement and I am raising the car up on ramps today to gain access.
Can anyone point me in the direction of a guide to replacing the starter either on here or elsewhere please as it seems access is very limited.

As a side issue I also purchased a set of genuine Jaguar factory manuals for the XK8 and they are light on detail when it comes to doing jobs like this. I see that Haynes dont do a workshop manual either. Cant see anything relevant on Youtube either. Does anyone know of a half decent source of info for working on this car ? ? ?

 

There is a wealth of information on this site:

JagRepair.com - Jaguar Repair Information Resource

Technical Service Bulletins (may not cover RHD cars):

JagRepair.com - Jaguar Repair Information Resource

Forum information:

https://www.jaguarforums.com/forum/x...ts-data-29800/

 

Okay I have trawled all of the info and come to the conclusion that its a lot of work as the steering rack has to come off before even starting on the starter motor replacement. Its too big a job for my capability. I want to get it to a dealer to have the work done.

The car is stuck in park in my garage and I cant move it as it wont start and seems to be unable to de-select park. I am not over familiar with these cars and at the risk of appearing daft here , is there a way of getting it into N so that I can move it and transport it to have the work done.

Thanks in advance.

 

The starter relay can click as it is being controlled correctly but the power contacts on that half of the relay can be bad not allowing enough current to drive the device ( starter motor ) . Known as pitted contacts or cat whiskers . You would see a correct voltage reading on both sides of the relay but little current .

Swap relay with one that has the same part # . Maybe the headlight , rear window defrost , heater pump ect.

Pacobeagle has a good suggestion on tapping the starter as a worn starter motor brushes because when they go bad it will damage the relay , the tapping would be a temporary fix . If this gets you results then it points to starter including relay replacement .

Have you removed and cleaned the large ground strap between the engine block and the car frame as that can be the whole issue ?

An open cell on the battery ( even a relatively new one ) can also show voltage but not deliver enough current ( cat whisker ) and can be removed and taken to the auto parts store for free and takes about an hour on a bench tester so plan accordingly

 

[QUOTE=Gus;1799404] You say the battery is only providing 13v at the battery after it has been fully charged and if that is the situation I would take it back and have it replaced.

Gus, are you sure 13v at the battery with the car not running is low?

Jack

 

Edited above post

 

In my experience with battery voltage and starting load 13v on a new battery fully charged is boarder line. I also feel that a battery for an XK8 should be rated with 700 reserve amps.

 

Check the large power wire terminal stud on the firewall as it sometimes gets loose . There are probably 3 studs that look the same large size .

https://www.ebay.co.uk/itm/JAGUAR-XJ...-/251272895122

This procedure may work on the XK8 :

https://www.jaguarforums.com/forum/x...ast-way-77394/

 

If your voltmeter shows only 9 volts you have a voltage loss somewhere. Probably a loose or corroded connection or ground. How many volts at starter? And how many with key engaged at starter? A new starter won't correct low voltage. And 13 volts will certainly engage starter if starter is OK and start car.