I have never had an issue getting my xjs to start but it always takes a few turns of the crank. Its not fuel pressure because I added a new valave to the fuel line and the problem still exists. I have heard others mention the same the problem. Has anyone solved it?

Would a faster starter or better cables help? Could it have anything to do with battery in the trunk? I ask because people are selling starter cables for other vehicles that are suppose to drastically increase the start time...

Or possibly a new crank sensor?

 

Turn the key all the way without turning the car on to allow fuel pressure to build and then crank it....If that works then it's a pressure problem although it may seem like your pressure is perfect

 

How many turns? Or cranking for how many seconds?

What is your expectation?

Are you sure you actually have a correctable fault?


Cheers
DD

 

No car starts the same moment the key is turned. Every 4 stroke engine needs a few turns to build up compression, injector fuel and ignite it...

The fastest car I've driven to start is my C30 with a high power starter. It takes a second. My V12 takes about 3 seconds... At the moment

 

Its not fuel pressure. I should have noted I already tried priming the pump. I went as far as a new fuel pump, new pressure regulator, I then added another valve back by the fuel pump to solve this issue. I also replaced spark plugs/ wires and distributor cap.

Someone else here mentioned they solved the same issue by doing something with the ignition. It may have been new coils.

I'm really just looking for others who are also trying to perfect their cars. I know the extra start time is normal for this car...

I'm thinking the battery in the trunk would require the cable to the starter to be possibly bigger than it actually is? or crank sensor? or coil? or possibly a quicker starter if they make one?

 

If you know (do you?) that the starter is cranking too slowly then it could be a resistance problem in the battery cables, or a weak starter, or a weak battery, or poor connections somewhere along the line. If you can't identify an actual fault in any of those then you could replace all of them and *hope* for some sort of improvement.

As for ignition, well, without an actual identified fault you're pretty much left with wholesale parts replacment that may or may not make the car start more quickly. So, yes, coil and crank sensor would be good candidates on the guesswork list!

Have you removed the injectors and had them professionally serviced? Can't hurt, might help....with emphasis on *might*.

How many spins of the starter does it take to start? Or how many seconds? Does hot engine/cold engine make a difference?

Cheers
DD

 

I noticed my Jag took a little longer to start than I'd expected, but I just chalked that up to needing a tune-up, or maybe just the extra moving parts. She sure as hell doesn't like the cold, though. She demands to be babied for five minutes upon start up.

My 500cc Royal Enfield, on the other hand, starts on the first kick and thumps along without a care in the world.

I'll be sure to keep an eye on this thread... In the meantime, I'm almost wondering if I put the wrong machine into winter storage

 

It takes 3 secs to start. Pump is primed and it does not matter if I shut it right off and right back on when warm. It always takes 4 secs. Someone previously mentioned his xjs had a delay in the spark. I will look into this when I get around to it. First I need to get this thing painted.

 

Turn the key to run, not start, pump the gas once. The key to run will run the pump making sure there's pressure to the injectors, the pedal down will pulse the injectors. Then hit the key to start. Changing to a new ignition amp module will also sometimes get better fire to the fuel.

 

I have a habit of letting the pump do its thing and hitting the pedal once or twice before starting it up. Other cars I have had issues with on long start-ups usually either needed a tune up or just some cleaning on the starter and battery.

my dad used to have a little 998cc morris with a giant mercedes battery in it, god that little thing started like nobody's business.

The V12 is a big ole beast to though, and obviously it takes more time to fire all the way around.

If you can I would try some resistance measuring, cleaning, maybe a tune-up if its time for one. As far as the battery being in the trunk, that doesn't really mean much, they cables are perfectly heavy enough to do their job. Make sure it is clean and well tightened while you are at it.

 

on the subject of instant start

I had an Austin Healey 1275 14:1 comp ratio...
2 su's later 1 45 DCOE
it only had 4 quarts of oil...
it only had 3 main bearings
the oil cooler was not bypass it was full flow...

I would just bearly bump the key and it would start...

now it did not have 7 main bearings and an over head cam or two to provide lubrication to... ect...

I really do not want my V12 to start right up... I would prefer it to turn over a few times and get some oil moving in the engine before the beautiful baby springs to life...

a pressure feed pre-lube oil system then I would not mind it starting right up...

 

3 seconds does not sound excessive. I would not spend much time or money trying to sort that out. If the engine refuses to start that is a different matter.
RagJag

 

To each is own. Its more like 4 seconds. I counted the cranks it was up to 5-6 cranks. It should start as quick as any other car imo. As of now there is a very noticeable delay.

Everytime I start the car it seems someone is standing there seeing if it starts. The small delay is a slight embarassment after I say how i dialed the car in to run perfectly...

 

Also, I do have the V12... and priming the pump does nothing for me.