Just this past weekend I went and picked up another el-cheapo XJ40. This time it is a 1988 car that has been sitting a long time.
See the photos below. The seller said he thought it ran about three years ago but he lost the keys to the car and it just sat after that.

When I initially went to look at the car I decided to put a deposit down on it and before I left I pulled the driver's door handle so I could take that to a locksmith to get keys made. Once I got the car back to my shop, I stuck a battery in it and used my new key to see if it would crank over. When I turned the key to the start position, the dash lit up but there was absolutely no sound at all from the starter. No click or anything. Like the ignition switch is not actually connected to anything or maybe the wire to the starter solenoid was fubar. The headlights and taillights work and one or two of the windows makes a noise like it might want to move.

Here is the description from the craiglist ad (sorry about the all caps typing from the seller):

FOR SALE IS A 1988 JAGUAR XJ6.. THE MOTOR AND TRANS IN THIS CAR IS STILL GOOD.. NOT BLOWN UP, RODS HANGING OUT THE SIDE, ETC.. WAS PARKED DUE TO LOST KEY.. HAS SAT FOER LAST 3 YEARS..NEEDS COMPLETLEY RESTORED.. DOES HAVE A GREAT BODY,DRIVE TRAIN, MOTOR AND TRANS, BUT NEEDS INTERIOR WORK.. THE SUN HAS CRACKED AND RUINED SEATS, ETC.. THATS WHY THIS SALE IS FOR PARTS CAR NOT RUNNING.. CLEAR TITLE AND CAR IS WORTH SAVING.. THE TIRES ARE DRY ROTTED BUT RIMS AND ALL MEDALLIONS ARE THERE..EVEN THE HOOD ORNAMENT..BOUGHT FOR PROJECT BUT FIXING A TOTALED TRUCK AND DONT HAVE TIME.. WOULD TRADE FOR ANYTHING..REALLY NEED FRONT END PARTS FOR 92-97 FORD F-150,250,350--GRILLE, CORE SUPPORT WITH NO RUST, HOOD, FENDERS, DOORS ETC..CAR IS TOO NICE TO JUNK AND STILL HAS POTENTIAL.

Could this no crank issue be a problem with either a neutral safety switch or inertia switch if there is one on a 1988 vehicle?
Any suggestions are welcome.




From the rear

Interior shot

 

Looks like a nice find. I dont care for the steering wheel though- maybe if it matched better. Not a bad design, just doesnt match. If other electrics work then start checking the starter circuit. Good luck, keep us posted.

 

I have extensive wiring diagrams for the later 4.0L XJ40 cars. Are the early 3.6L cars like this noticeably different?

 

Hi have you information gear "P" on dashboard. If not try to gear position in "N".

 

Thanks for the suggestion Marc
I did try both Park and Neutral position for the gear lever.
Same result in both, Nothing, no clicks or any action at all.

 

Might be the shift inhibitor switch -
Normally it earths one side of the starter relay when in Park, and prevents starting in gear.
Sometimes stops working in any position so the starter relay does not operate at all
On my 1991 model it is located on the LHS of the shift, need to remove the center console trim around the gear shift to get to it.

 

Hi it's not necessary remove linear switch if you have position information on dashboard it's ok.

 

Hi Steve,

Sorry to join your thread late. You can download the Electrical Guide for the 3.6L cars at the link below:

Jaguar XJ40 Electrical Guide 1987-1989 3.6L

As a quick test of the starter, remove the starter relay and use a paperclip bent into a U to jump terminals 30 and 87 in the starter relay socket. I think the starter should crank regardless of the linear switch or inertia switch positions.

The inertia switch is usually in the outboard corner of the driver's footwell behind the carpet. A plunger pops up when the switch is triggered. Press it down to restore normal function.

One possible issue is the engine ground strap, which connects a starter bolt to the body.

Looking forward to hearing what you find.

Cheers,

Don

 

This evening when I was too frustrated to work on my 1994 car with the blowing fuse and dead battery, I decided to drive over to my shop and try some things on this derelict 1988 car that sat idle for a number of years. I was able to locate the starter relay under the passenger's side of the dash. I inserted a jumper lead across the 30 and 87 pin sockets in the relay socket and the engine spun over just fine on the starter. I did have power on the sockets for pin 30 and one of the relay control circuit pins. So I think as others suggested I probably have to look at the linear gear position switch in the center console. However after I started looking at the wiring diagram and went to look for the overvoltage protection relay. When I pulled on this relay to try and remove it from it's socket, the plastic cover came off the relay and this is what I found inside:


Very rusty OVP relay

 

Over a year later and I am still attempting to get the starter relay to spin the starter over on this car when the key is turned to the start position. I have tried replacing the linear gear position switch inside the console but that had zero effect on the problem.

This evening I went over to the place where I have it stored again and investigated the wiring again while referencing the diagrams from the factory electric guide for the MY88 - MY89 3.6L cars. I discovered that some DPO had an aftermarket security system by Alpine installed into the car. In my experience these aftermarket security systems from ages ago just cause no ends of problems when they are layered on top of the factory wiring by some ham-fisted installer dude.

So I ripped all of this extra wiring out of the car (see below for a photo of all of the ripped out wires and the actual security system unit). I then reconnected some wires that had been cut to install this system. In particular I reconnected a red w/white wire coming out of the ignition switch that I believe is critical to the operation of the starter relay.


Alpine Mobile Security System and wiring bundle Unit has a Part # 8026A

Unfortunately after doing this there was no change and the starter still does not engage when the key is turned while the gear selection lever is in either the park or neutral position. If I go to the actual starter relay and supply a ground signal to the terminal with the white w/purple wire that goes to the linear gear position switch the starter does engage and spins the motor over. However when I turn the key from the on position to the start position I can hear a clicking from under the passenger's side of the dash. So I dropped the trim panel that covers the underside of the passenger's side of the dash and carefully listened to see if I could identify where this clicking sound is coming from. It turns out when the key is turned from the on position to the start position it is a relay with a black base that is clicking. If I grab the relay with my hand I can actually feel the relay clicking when the key is turned from the on position to the start position. However I do not know what relay this is that has a black socket. The other relays in the same location have sockets that are red, green, yellow, white and pale blue. I looked in the MY88 Electrical guide and I did not see a page that identified the relays based on location or socket color.


Relay with black socket that is clicking when key is turned to start position.

All six relays from under the passenger's side of the dash. Socket colors are black blue, green, white, red, and yellow.

I am hoping that knowing what the function of this relay has will somehow help me figure out why the starter relay does not get energized when the ignition switch is turned to the start position.

 

Hi Steve,

I think the Workshop Manual identifies the relays by base color, but there is also a diagram in the Haynes manual. You can download a mostly-complete U.K. edition at this link:

Jaguar XJ40 Haynes Repair Manual

I'm pretty sure the starter relay is in the yellow base. I can't recall what the black base relay is.

Cheers,

Don

 

Hi Steve,

I think the Workshop Manual identifies the relays by base color, but there is also a diagram in the Haynes manual. You can download a mostly-complete U.K. edition at this link:

Jaguar XJ40 Haynes Repair Manual

I think I recall that the starter relay is in the yellow base. I can't recall what the black base relay is.

Cheers,

Don

 

did you try the inertia switch in left foot well?

 

I looked for the inertia switch but I have not been able to locate it so far.
Can anyone post a picture of this elusive thing so I know what I am looking for?

 

On LHD cars, the inertia switch is in the forward outward corner of the driver's footwell, behind the carpet and trim. It's a small black plastic rectangular enclosure with a plunger on top. If the plunger is up, the switch has been tripped. Just push the plunger down to reset the switch. In our '93 it was mounted above the battery power connection box. it's visible in the upper right of this photo:



Cheers,

Don