XJR '96 X300 Turns over, but won't start. Died slowly

(Dragan Mihailovic) #1

XJR '96 X300, VIN 766138, owned since 2001!
First the engine cut out a few times on driving (check engine light came on momentarily), then it didn’t want to start a couple of times. Towed to garage, who cleaned the spark plugs, but that didn’t help for long. The plugs were pretty sooty. Cleaned up, helped for a short while, but symptoms continued. Now it won’t start at all.

Now I’ve done (almost) everything that I could find on the forum, but no luck so far.
The tachometer shows about 100 rpm on turning over. Tries to start, but it sounds as if only one cylinder tries to fire, if that.

Checked so far:

  • No ODB2 error codes now (previously P1621, which cleared when I recharged the battery after so much starting)
  • replaced crankshaft position sensor (made no difference)
  • checked ECU contacts and harness. Seems fine.
  • checked PI1 connector: seems fine.
  • spark plugs are wet (smell of fuel), cleaning plugs makes no difference.
  • checked fuses 6, 11, 12, 14 in front RH fuse box, all OK.

I’ve run out of ideas. Please help! I really like the car.

(j limongelli) #2

You sure the pumps are okay?
How many miles…

(Dragan Mihailovic) #3

Hi j_l, you mean fuel pump? (220 000 km)

(Robin O'Connor) #4

Sooty plugs would indicate that the pump is working, try disconnecting the coolant temperature sensor, sounds like the car is over fuelling, you might have flooded the car so try starting it with the accelerator pedal to the floor to cut off the injectors. Make sure the battery is fully charged.

(Neil Bennett. Patron) #5

I would try and get hold of a set of OEM Coil packs and try those with clean plugs, the X300 will drive quite happily with 2 coils not working as I found on mine the only symptom was an uneven idle which could only be identified by feeling it through the seat of my pants.

(Dragan Mihailovic) #6

Neil, thanks for the suggestion, wouldn’t there be a ODB error code if the coils aren’t firing?

(SD Faircloth) #7

If you disconnect the CTS electrical connector to see if it is faulty…you ALSO have to jumper the pins inside the wiring connector harness with a short bit of wire. If you don’t, the ECU will “think” the engine is stone cold and enrich the fueling to the max limit of that table.

By jumpering the connector, you are eliminating the CTS from providing any feedback voltage to the ECU. In essence…testing the CTS. Jumpering the connector pins will NOT prove if the wiring connector or the wiring harness is good. That is best performed by ohm testing.

SD Faircloth

(Dragan Mihailovic) #8

Robin, thanks for the suggestion. Now I understand why the CTS is relevant in all this. I’ll try this next. Will let you know what I find.

(Dragan Mihailovic) #9

Disconnecting CTS and shorting the wires on the harnes has no effect, sorry to say.
But an error code shows up :

‘P1621 Ford: Immobilizer Code Words Do Not Match’

Hm, What does that mean?

(Dragan Mihailovic) #10

I forgot to note the resistance pf the CTS is about 4kOhms, the harness resistance is about 2kOhms, from which I conclude that it’s not broken or shorted.

(j limongelli) #11

Ok I get it now, your cranking but if continue you kill the battery.
Your getting an alarm code shutting down the spark or anti theft.
If Im getting this right.
If you can simply pull both battery cables and wait 30 minutes.
Recharge the battery and see if it reboots.Hopefully there is no MOUSE around shorting out systems……
Its been happening a lot latelty.

1 Like
(Dragan Mihailovic) #12

Hi J_L, indeed you are right. The battery reads 11.8 V, and now needs recharging. Will continue tomorrow.

(j limongelli) #13

Pray for a reboot my friend, ALSO make sure your both key fobs are not JAMBED and sticking in panic or alarm mode. Its all old stuff.
When you put the battery back on you might lose the radio code and fault will show. Hopefully you have the code if not call a local dealer.
Those cars are bullet proof, send pictures…….

(Neil Bennett. Patron) #14

ODB is not always definitive on an X300 I had no codes whilst firing on 4.

(Dragan Mihailovic) #15

It looks like the coils may be a problem. A few years ago, I changed the 6 with new ‘Lucas’ ones from ebay. Now I see on various threads that they are suspect/fake/unreliable. Originals from the Jaguar service are 400 EURos each! Eurospares are recommended in a few places. Any suggestions?

(Robin O'Connor) #16

I purchased 16 from a Chinese site a couple of years ago <>$NZ16 each, they have been in my XJR for the last 18 months and operating fine, I use the car for a bit of track work and also a road rally (Targa NZ) on the Tour (max 130klm closed roads) I still have the balance in the garage, I purchased 2 sets as the brother has an X308 as well.

(j limongelli) #17

I doubt all coils failed, your code is reading nothing per bank correct.

(Veekay) #18

Just to respond about coils…

You have two known options.

#1: Purchase the OEM brand: DIAMOND, Made in Japan - NOT LUCAS!!! SNG Barratt sells these Diamond coils, as well as a few others. SNG is reasonable, so if you can order from them, Dragan, I would.

#2: Some people have had a good bit of success with QYL coils, sold on Amazon. You basically get six coils for the price of one Diamond…I have no personal experience with these coils, but if you’re troubleshooting, they would be worth the gamble.

Stay away from Lucas. Stay away from Eurospares. Stay away from all other brands. The only two worth chasing seems to be Diamond and QYL.

(Robin O'Connor) #19

From personal experience I would have to disagree here.

(Veekay) #20

Can you please share your experience?

There are several threads that track member experiences with different coils. Most fail within six months, the rest seem to fail within twelve.

Even the QYL are not consistent, but enough people have had success with them that I put them in the “worth the investment” column.

What coils have you been using successfully, and for how long?