I have a problem with the starter in one of my xjs:
it worked totally fine until i changed the starter relay (on the search for a sporadic appearing "not-running" engine problem. i swapped in a new relay and tried to crank it.....dead. swapped it back to the old relay.....still dead. i think i can hear the relay engaging and the solenoid engaging but the starter motor does not turn. is there any fuse somewhere that might cause this? it is my only explanation that i blew some fuse. suggestions? is there any relay in the main power supply for the starter motor or maybe a fuse?

 

I assume this is a V12 - yup common problem I replaced my started twice the last time was with one of those reduction gear units, much lighter and easier to get in and out and last much longer I believe. No more problems.

If you do this yourself there is a 7/16 bolt that goes in from the gearbox side at the top RH side of the bellhousing, this is PITA to get at, take your time and use a 12point 3/8 drive socket with a short extension on the bolt connected to a universal to a long extension and did I mention take your time.

 

OK, as Warren said, is it a V12??.

If so read on, if not, stop now.

Trace the White/Red wire from the starter relay, and you will find a spade type joiner in it about where the scuttle drain tube is at the firewall. Seperate that joiner and clean the contacts. Replug, and ensure the insulated boot is fitted correctly.

I find the relay is generally OK, and that joiner is the culprit. OK, dirty/burnt points INSIDE the relay are an issue at times, and easily cleaned.

Also, use a volt meter to ensure you actually have 12v in that wire when the key switch is in the "start" position.

Just near that joiner is a battery cable +ve stud, with a rubber cover protecting it, and it has a battery cable that goes direct to the starter solenoid, and it can cause voltage issues as it gets dirty and sometimes not so tight, so disconnect the battery, remove the nut (dont drop that sucker, it is s special thread), and clean the cable eyelets etc, and refit and tighten.

 

problem solved:
i found a partially loose cable on the VE+ point.....which is on my cars (i have two 85 xjs v12) just left to the starter relay under a cover - right hand side in the engine department. hard to find problems like this, actually.
Thanks for your help!

 

Thanks for replying, that is a rare thing.

ANYWAY, is it a V12, or a half sized engine, MMMMMMM.

 

Good work.

I'd make it a point to check/clean/tighten any and every connection (and ground point) you stumble across as you perform various other tasks on the car. Changing a tail lght bulb? Allow an extra 30 minutes to clean connectors, grounds, and sockets at both tail lamps. Replacing a relay? Allow 30 extra minutes to clean/tighten connections of the other nearby electricals while you're at it. You get the idea :-)

Or just make a Saturday of it and do 'em all at once....or as many as you can find, at least.

It'll go a long way towards keeping the car reliable.

Cheers
DD