1990 Jaguar XJ12 starting issues

VEGARD

MEMBER
1990 JAGUAR XJ12
221,000 MILES

Hi.

I have a jaguar xj 12 double six that won't start, when I bought it the starter motor was broken problebly because the previous owner had the same problem.
So I have change the starter motor, all 12 spark plugs, Distributor, rotor, the plug cables and the fuel pump.
Tried to start it today and it start right up, runs for 20 sec(like it should) and then stops, tried to start it again, nothing happen.
I then took out the spark plugs and they were dry but black of soot. To me it seams like it is an electronic fail that's stops the fuel to go in to the injectors.
Best regards Vegard

5 Replies

MHPAUTOS

MECHANIC
31,938 POSTS

May be running too rich on cold start and fouling the plugs, black sooty plugs are a sign that it is running way to rich, are there any fault codes in the system, not all fault codes will set a MIL.

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Saturday, September 14th, 2013 AT 10:23 PM

VEGARD

MEMBER
4 POSTS

Sorry that I missed a detail, the old plugs was sooty and dry, and when we putt the new one in it started right up and then died out.
We tried to start it a few times but it was completely dead, we took the plugs out and they were dry not any soot just dry.
But if it stand for a month or more, it starts the first time and then dies again.
So to me it seams like something is blocking the fuel to go in to the cylinders.
You can hear the injector clicking and you can feel the fuel goes to the fuel rails.
And if you give it full throttle it's so close to start but still dead and you can smell the petrol.

Thanks for answers

best regards Vegard

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Sunday, September 15th, 2013 AT 12:46 PM

MHPAUTOS

MECHANIC
31,938 POSTS

Check fuel rail pressure, check filters, start here.

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Monday, September 16th, 2013 AT 2:27 AM

VEGARD

MEMBER
4 POSTS

Hi, again.

We tried to change the fuel filter, vi also checked the fuel pressure.

It was at 2, 6 bar. As soon as the fuel pump have build up the pressure it drops quite fast, checked for leaks and it was none.

Do you think it could have something with the injectors, or det fuel pressure regulator on the return side?

Thanks for god help!

Best regards Vegard johannessen.

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Tuesday, November 5th, 2013 AT 1:09 PM

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