1996 XJS convertable Hard starting 4.0 engine

Jag. seems to have to crank a little too much to start . Past owner changed Battery and fuel filter. Any thoughts?

V12 or 6-banger?

20 char

That question seems almost redundant as the title of the post says “1996”. There were 3 (three) V12 cars in 1996 and I don’t recall ever hearing about their owners on this forum.

1996 US model was manufactured in 1995. So are you talking 1996 model or 1996 manufactured?

When is the last time the whole ignition system was updated, especially the spark plugs?

Unknown Just bought the car, When it runs it’s like a Swiss watch. Seems to only hard to start (too many RPMs until it kicks over) when it’s cold . Battery is weak I think and it only has 550 CCAmps anyway I am going to pop for a premium batt first off. It is a 4.0 engine

If its a V12, that’s way too low. Mine is 800 CCA.

Another issue, which would apply to L6 too, if the fuel pump is not creating enough pressure at startup.

Put that info in the avatar, will help with staying on target with the question and answers.

The weak battery could be one of your problems, but it could be insufficient fuel pressure, spark, etc.

The previous owner put a new fuel filter in the car and a new alternator, I am going to inspect plugs and put a fuel pressure gauge on it to see what it puts out. so far it needs all new wood (I have to figure how to remove it ) to refinish. Drivers seat has an issue not going back, He butcherd the cover on the steering columb installing new sw. lost the key so he bought all new locks . Paint on the bonnet is amature at best, may need to respray it .

Hey guys, it’s in the title of the post!!!
It’s a 4.0.

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It’s always the crank position sensor until proved otherwise, even if you replaced it three months ago.

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Prolonged crank to start could be associated with the cam position sensor located in the newish distributor shell at the right front of the AJ16 engine.

A new happy battery is your first requirement, though.

Hay Steve. Title yesterday did not have the engine specified in it. The OP edited after it was pointed out.

Where is this part on my Engine? I think I will CO just as a precaution .

Removed the Ski slope today I think I can luck out I mandaged to clean off all the clear coating without damaging the veneer… Now to figurge out how to remove the dash panls , Found a 750 CCA battery from Home Despot I am going to buy it as I get 10% off For Veterans… disc.

The crank position sensor is right near the crank damper on the front of the engine. It is accessible from the top down, if your arms aren’t too fat. My car has two…. One on the engine and one in the trunk along with a 10mm socket and ratchet so I can change it out whenever I want. I’ve tried all brands, they never make it past 30k miles any more. One New Hampshire winter, max, no matter the miles.

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I put my OBE reader on it and it kicked a code Crankshaft sensor

Common issue, and easy to replace yourself!


I Insalled new sensor now the engine will start on 2nd crank .