I was enjoying my re-animated Jaguar XK8 until several weeks ago when it wouldn't start after a fairly long drive.
After pulling apart various components and cranking away with the ELM 327 diagnostic reader attached, an 0706 code popped up. (Rotary switch/D4 microswitch related) I rowed the J-gate and the car started right up.

Drove it for a week. Back of mind to get new microswitches.

One week later, same thing. No start after a pleasant drive. (I say pleasant / long drive to eliminate bore wash as car was thoroughlu warmed up..)

This time, I fiddled with the J-gate cable so that the gear lights light where they should. Still haven't dived into the microswitches, but also have not seen an 0706 again....I have heard a high pitched beeping before starting in the past week.

In fact, just seeing P1000...though there is an engine fault on dash (which has been there intermittently...as a DIY guy, I work on stuff, but don't always get it first shot.)

Also, just got a new exhaust system on car.

Also, have driver's side door panel issues (missing a couple clips).

You get the idea...work in progress car...but all systems - hvac, lights, cruise, etc....work)

These things aside, I want to get the car started. It's in my driveway. I have a garage, but it's not at my house so have limited ability to work on it. (Don't like rolling around on cold concrete).

Next steps: Brake clean throttle body (suggested in another thread...this car had a lot of goo in the TB when I got it.)
Swap more relays...in particular related relay in trunk.

(Hoping I don't have to revisit transmission strap...been there.)

Any new ideas...I have a no start list and am reaching the end of it.

Thanks everyone !

 

First check for fuel and spark.

Gus
www.jagrepair.com

 

No spark. No fuel to the injector...I pulled a plug. Grounded it / and used a tester...No Spark. Fuel rail is getting fuel, but the plug appeared dry, save for a slight whiff of gas (residual?)

Going to put the tester on it this afternoon in hope of finding something...But still at whit's end.

 

If you have fuel but getting no spark it is possible that the carankshaft position sensor has ffailed and is not telling the ECM that the engine is rotating. The ckps tells the ECM you have rotation and will then provide spark.

 

Check your fuses and swap your relays.

Gus
www.jagrepair.com

 

Forgot to suggest you look at the adjustment of the shifter cable. If it is adjusted to specs then look at the fuses and relays.

Gus
www.jagrepair.com

 

Following clues here: Should the tachometer register a few rpm s (needle slightly lifts) when the engine cranks.

What else will not register on the dash if there is a problem in the wiring between the shift lever and dashboard ?

Other than the wiring in and around the shift lever, what fault, if any, will affect the operation of the tachometer or other dashboard gauges?

Thank you.

 

No start. No reading on tach when cranking. Codes 0706 and 1638.....Started once before after rowing J-gate, but no longer.

(Re: 0706...recently installed a new/used transmission and it has been working great.)

My diagnosis is to get a new J-gate.

Does anyone concur or disagree?

Thank you.

 

What about the crankshaft sensor? If the tach doesn't register that's a possibility.

 

The j- gate only reads the selector switch on the side of the trans you need to see if the mounting bolts are tight and that the shifter cable is adjusted properly. As for the crank sensor it would 3a good idea to check of it is mounted correctly.

Gus
www.jagrepair.com

 

Under normal circumstances (car is inside at my shop) I would check the crankshaft position sensor and the rotary selector switch. I could still do it, but just had some surgery so am avoiding the cold concrete under the car.

However, I am 95% sure it's not the crankshaft position sensor as I have replaced that - a bad one shows up on OBD II as well.

The transmission adjustment is more likely...though I have spent considerable time adjusting the cable from above the car. The rotary switch was replaced on the last transmission...It could have been installed loosely on this one...and certainly the transmission lever (which connects to the cable under the car) could be out of adjustment.

All excellent suggestions my friends....

However, since the cost of a tow approximately equals the cost of a used J-gate...I'm going to try the J-gate, realizing I could be wrong, but thoroughly afraid of cold concrete.

Thank you for the alternatives. Will let you know of the outcome....if this doesn't work, I'll have it towed to a nearby Indy and leave the diagnosis/repair to the experts.

 

This is the TSB on the shifter cable adjustment. With the recent trans change I would be checking it first.



Link http://www.jagrepair.com/images/TSB/307-01-1.pdf

Check your PM.

 

Got it started (finally)....

0706 / No tach operation = Transmission Selector/Rotary Switch...Amazing how accurate the code reader is...

Also, thanks to Gus, who discussed my problem with me, and nailed it.

I didn't believe it was the rotary switch because I had already replaced it once (with an eBay purchase of uncertain age).

However, I happened to have a spare after replacing the transmission.

(Hopefully there isn't something in the system causing the rotary switch to fail ! ?)

Didn't much want to climb under the car but FYI in case someone is considering it, the switch is easy to replace. The trick is to connect the switch on the top side, drop it down and then replace the switch...which only has two 10 mm bolts.

Finally...to add to the database of no-start conditions....No start and No tach is likely to be in the area of the J-gate and selector switch....

(I had a previous no start / no tach caused by a connector in the area...which is why I originally focused on the J-gate and associated connectors.)