Hi All, Been a while.

My father pulled the 97XK8 out of storage which was in his back garage.

Started the car and drove it up to the front garage and let it run for 10-15 minutes. Put the top down and was going to go for a ride. Turned the car off to go do a few things. Came back and car won't start, display shows Engine Fault.

Cruised over to give him a hand and take care of a few things, light bulbs on dash needed replacing, and AC control module needed to be replaced.

This was an intermittent fault I had before giving him the old gal. Thought I had fixed it but guess not, and now it's not intermittent. Whatever is causing has finally given up.

Car was stored over the winter with battery maintainer.
New AGM battery installed a few months prior to storage.
New plugs shortly before battery.
Replaced a couple of the coil packs I thought may have been bad.

Threw the innova 3100 tester on it and no codes, same as what I always had before when this fault would occur.

So my guess is that it is something either that doesn't register a code or my reader can't pull it.

The fault properties when it was intermittent were after longer drives of an hour or more, if you stopped the car then try to restart shortly (5-10 minutes) there after, you had a chance of a no start and the 'Engine Fault' code come up. Car would not start but after 20 minutes or so would start right up and run perfectly fine, and no codes displayed. Eroor wouldn't happen again for a while.

Did have it happen once while doing a bunch of errands that were short trips, stopped for gas and wouldn't start. A little embarrassing but only took ten minutes for it to start that time.

Now one thing I noticed today is that there was a humming sound coming from the engine area.

I pulled the coil covers and checked connections. All good and no noise coming from coil packs.

Remove intake and sound was coming from throttle body area. While humming was going on I removed the large connector from the passenger side of the throttle body and no more hum. Not sure if sensor is bad or something else.

Anyone have a similar fault or a good way to troubleshoot.
May have to take it to a dealer to troubleshoot but would prefer to drive there

I took a couple of videos but could only get the one of the hum to upload.
Other is a pic of the dash showing Engine Fault. Car cranks fine just won't fire.

 

Could be the fuel pump...Check for fuel pressure at the valve on the injector rail.



Dave

 

Fuel pump is good as you can hear it kick in when you turn the key and there is gas pressure in the fuel lines.

It's just a weird fault that doesn't throw any readable codes I can pull. Figure it's a sensor of some kind where if the engine doesn't detect something it doesn't allow the fuel to flow.

Replaced the Fuel Ignition relay and Ignition Coil Relays that were located on the passenger side of the engine compartment Thinking maybe one of those failed after 18yrs but apparently not that. Wasn't much for the relays, got them from the dealer for $6.00 each.

First time I've heard the humming from the throttle body though, It's an electrical hum and if I put my hand on it I can feel a light vibration.

 

That sound is the throttle body motor. Note that it can e risky to disconnect anything without first removing negative battery terminal, but we all do it occasionally.

The problem could be the throttle position sensor. A lot of threads discuss this if you do a search. Throttle body problems do not always result in codes.

If you haven't cleaned the throttle body and butterfly do that, paying attention to a possible ring of gunk around the area where the butterfly closes. But don't spray cleaner in there, use solvent on a rag.

 

Thanks RJ,

I did a search on engine fault but wasn't able to find anything useful, I'll try a search on the throttle position sensor.

And yeah I'm sure the throttle body is due for a cleaning.

 

OK Guys, I think I found my problem. Did a google search and found a post from bigdude back in 2010. His situation seemed identical to mine. No start, throttle body humming. Did use the forum search but could not find and I knew there were multiple threads regarding this topic as I read them back in 2010.

Start Inhibit

The rotary switch also provides the start inhibit function to the ECM, which will not allow an engine start until the gear selector is in either Park or Neutral

Saw some postings about this from Jag mechanics on FixYa and RoadFly as well that said the process 'denies fuel supply to the engine' so you get cranking but no start.. I then did a dry cycle of gear positions about five times with the key in the on position and got a new code P0706 (trans position switch range problem). Both of these codes tie back to the rotary switch as the crank no-start condition I am getting does, so I am hopeful that I may be on the right track.

I read about the connector filling with water on one forum, and about the switch failing on others. Before replacing it I want to disconnect it and check the connectors. The problem is that it is a real B_tch to reach. I was wondering if any of you might know how the connector actually unlatches. I can just barely get my hands into it, and I have to work blind once I do.. This is a black ten pin connector clipped onto the driver side of the engine harness block [LH Drive] (and as luck woudl have it this is the only connector I could not reseat before because I could not get it apart !).

Not sure if it is the rotary switch at this point or a cable adjustment which I'm hoping it's the later. Looks like the switch is a pain to replace.

Had my father cycle the gear selector and said there was no light in Park, R,N, and Drive illuminated. On J gate 4th didn't illuminate but 3,2 did.

Also would not let him start in Neutral position and a transmission fault came up when he cycled to J gate side.

I had that fault shortly after getting the car and was told by Jaguar they just made a cable adjustment to correct. No fault in P,R,N,D though and never really used J gate as car could accelerate faster than I could manually.

Keep you updated and may want to add the rotary switch fault as a possible reason to the 'no start' sticky.

 

Went today to do some inspecting.

First checked the micro switches at the J-Gate. There are three, one for park, one for neutral, and the last is to detect when you slide the shifter over from drive-4th.

Park switch and drive switch are ok but neutral switch is broken, will have to replace, but that's why when we turn the key in neutral nothing happens, no crank at all. In Park it will crank but no start, but if you pull it towards reverse a little then same as neutral, no crank at all.

Quick Note: The micro switches for park and neutral are Normally Closed meaning when you are in park or neutral and the switch activates it actually breaks continuity in the line.

Next moved onto gear selector cable. Not really sure how adjustments this. Could see anyway to adjust at the J-Gate. Below on the drivers side of the trans is the selector. There is a rubber boot there and it connects to an arm on the drivers side of the trans. There was a connector with a nut and the assembly looked a little rusty so it doesn't look like it moved at all, unless it stretched and needs to be tightened a little.

Finally the Rotary Switch. It's on the passenger side directly across from the gear selector. Tried to follow the electrical connector but had a hard time locating. Car up on jack stand and crawling under then over gets a little frustrating. Saw two gray connectors and one black which should be it, but directly behind the throttle body and we were outside and the sun wasn't helping any. So gave up as I had to get going and we needed to move the car back into the rear garage. Need to remove the intake at least to confirm.

I will try to get back at it later this week as I need to check for continuity across pin J and K on the 10 pin EM47 connector which is for the internal Park-Neutral in the rotary switch which is the one I believe actually signals the fuel cut-off. The ones at the J-gate just appear to say I'm in Park or Neutral so it's OK to crank.

 

Success, Success , SHE'S ALIVE

Found the instructions for adjusting the gear selector cable and that's what it was.

After the readjusting the cable she fired right up and all is well.

Thankfully didn't have to check rotary switch as you need to pull the wipers and cowl just to access the connector.

 

Adjustment procedure for gear selector cable I used is (differs slightly from instructions I found in regard to nut tightening sequence);

1) Place car in Neutral at J-Gate.
2) Remove Center Console and Trim Panels to access the two nuts that hold the cable in the bracket.
3) Loosen nuts and move nuts to end of threads in each direction.
4) Raise car to access gear selector lever on drivers side of transmission. (LHD)
5) Remove connecting link to gear selector lever (10mm socket).
6) Pull transmission selector lever fully rearward which would put it in Park.
7) Ease lever forward 2 positions which is Neutral.
8) Replace connecting link and hand tighten nut, ensure shifter at J-Gate is still in Neutral.
9) Hand tighten nuts at J-gate till each nut touches bracket, then fully tighten nuts.
10) Move to Gear Shifter to Park then finish tightening nut on connecting link. (reason I did this is if you tighten connecting link nut fully before tightening nuts at J-gate, the transmission arm may move when tightening connecting link nut and you get to start over)
11) Lower car and hopefully start it up, if not then rotary switch may be bad.

I attached a couple of pics, first is of the J-gate area and circled the nuts in red. Second is of the gear selector under the car which can be quite difficult as there isn't a lot of room unless you drop the exhaust or can put it up on a proper lift compared to on your back under the car.

One indicator is that before I adjusted the cable, when the car was in Park the P was not illuminated, after the adjustment you can see that it is.

So if you have a crank but no start condition you may want to look to see if P in park is lit up. If not then you may need to adjust the cable or your rotary switch may be bad.

There are two micro switches in the park and neutral position at the J-Gate and these control whether or not the engine can crank.

As I mentioned earlier nothing happened when we turned the key in neutral as that micro switch was broken, lever was missing that actuates plunger.

The park switch was OK but because the cable was out of adjustment the rotary switch internal P-N switch denied fuel to the car as it didn't know it was in park.