Good day everyone, new subscriber here.. I've had a look at posts but can't find the answer yet. I left my car at local garage for brake pads, and they couldn't get it started. I had driven there and parked it. Anyway, they're not a Jaguar specialist, but they did go thru fuses, etc, and came to the crankshaft sensor which they removed, cleaned off some swarf, refitted, and the car started for about 15 seconds, then back to cranking but not starting. .They said the ECU was registering crank positions they couldn't understand and sometimes nothing. Its stranded in their garage, and the two nearest Jaguar garages are booked up for 7 weeks. My thought was to take a chance that it is this sensor (could be connector or cable) and buy a replacement. Talking to parts departments, they told me there are two of these, one right and one left, costing about 40 pounds each. The garage told me they had looked and the price was 200 pounds. So I need some help. They're a good garage, but they're not good at specifying Jagparts. They once told me I needed a certain suspension arm, and it was the wrong arm they told me they needed. They couldn't get it because its discontinued.
I don't want to buy the wrong thing, or two if I need one, or is there any other possibility?
thanks

 

LCA1640AE Crankshaft position sensor located underneath the engine at the 6 o’clock position. You have an AJ26 (early V8) and this is the one you’ll need so the £200 sounds about right. The later AJ27 engines have a 2 pin sensor only and those are cheap and NOT interchangeable. I think I’ve only replaced 1 or 2 at most so I’d be suspect on just throwing a sensor at it. Did they get a code for the CPS? Maybe they should check for fuel pressure at the rail. Does it have enough fuel in the tank?

 

The AJ26 sensor has the link harness and the AJ27 is a 'plug-in' sensor.

Technically they are interchangeable BUT, you have to make an extension harness for the AJ27 sensor to get the AJ26 wires from the area at the back of the A/C compressor where the AJ26 connector is.(I used old AJ26 and AJ27 engine harnesses to fabricate the link lead)

I made one when I worked at the dealer but I must admit I never found a CKPS to be faulty so it was just a 'test harness'.

 

Thanks for the insight Bob. I had thought about that years ago but, I never got around to trying that and I had forgotten about it until you mentioned it.

 

Thanks for the insight Bob. I had thought about that years ago but, I never got around to trying that and I had forgotten about it until you mentioned it. Even the one on my daughter’s 98’ XJR with 282k miles on it is still working. We have records on it back to when it only had 100k and no mention of a no start due to the crank sensor.

 

There is some confusion here. The "one right and one left" refers to Camshaft sensors on AJ27 engines, one on left and one on right cylinder head. Your AJ26 has only one Camshaft sensor and it is on the left cylinder head.

Did your mechanic say the problem is in the Camshaft or Crankshaft sensor? Did they remove and clean the sensor on the left cylinder head or the sensor at the bottom of the bell housing?

If the Camshaft sensor is a suspect, you can try with first keeping the ignition "on" for some 40 sec. then crank the engine. If the engine starts using this method, it means bad Camshaft sensor.

 

Thank you everyone. All of these replies have been incredibly useful.
the mechanic said the sensor they removed and cleaned and think is the problem has a long cable with no plug on the sensor end, that disappears up behind the brake servo and air con reservoir (so looks like the part in the photo), they couldnt see exactly where, and thought they might have to take those out to fit the other end of the cable. My regular specialist garage also mentioned they thought it more likely that it was fuel pressure cos they've hardly ever replaced a csps either. The car' covered 76,000 miles. When I spoke to my mechanic after that they were sure the engine was getting fuel and spark and that it was the csps because the ecu was giving readings that didnt make sense - and sometimes nothing, though they havent checked actual fuel pressure. The actual part is on back order at Jaguar, so I have to get it from a Jag specialist parts company who quoted me 56.00 express courier which is a bit more riskable. I'll go with that to start with. The company I'm getting it from says its a bit of a fiddle but shouldn't need to remove brake or aircon components - would that be correct, or do you have to have done it before and know where it plugs in by feel?

 

check for injector pulse. if yes it’s probably flooded from being moved around the shop for short trips..the nikasil motors love to do that

 

They couldn't start it at all after I dropped it off. Then the first thing they did was change the spark plugs and it still didnt fire. I would have thought that could clear potential flooding. Its never failed to start before so unsure why it would be flooding all of a sudden?