I've a Facelift 94 XJS with Auto AJ16 engine that has rarely started properly since a snowy winter. The starter motor turns over but the spark is weak and the engine does not fire up (it has twice but then cut out over the last few months). Fuel lines and pump are fine and fuel changed for fresh.

I have systematically replaced with new parts:
battery
spark plugs
all six coils (some were cracked)
crankshaft sensor
engine position sensor
ECU (part LHE1410) - not new but tested and PROMs upgraded although BE/701 changed for slightly different AL/601 part
but still nothing!

Any other bright ideas from anyone?
Anyone have a relevant wiring diagram or recommend a mechanic in South East or Midlands of UK?

 

Check the security system. IMO as these cars age the key fobs and security systems are becoming problematic.

 

Sorry to hear you are still having problems.

Sometimes these cars won't start after they have been driven a very short distance (like moving around in the driveway) without heating up, and the next time you turn them on you really have to step on the accelerator to force them to start.

Another possibility is your inertia switch. Perhaps it's been set of

Any chance you can make a YouTube video of what is happening when you try to start her up ??

 

You say you have a weak spark. Is that before or after you threw the parts at the car?

Cause if the spark is still weak after replacing the parts you mention, I would suggest the spark cables...

 

here's a vid of trying to start. battery fully charged. new parts in use.
what do you think?

spark cables not changed but they look good. new coils include a new housing for plug.

security blipper appears to alarm and deactivate well.

 

Please tell me you've already tried pressing the inertia switch button. You'll find that on the right end of the dashboard, with the passengers side door opened.

 

Sorry to state the obvious, but it seems like there is no fuel in the car as the gauge does not move...perhaps this is the problem??

Also, there are no spark plug cables on the AJ16...plug on coil.

I doubt the security system is at fault. I have helped a few people who thought their security ECU was fried and not once has that been the case. I actually believe the security ECU is a pretty bullet proof part myself.

 

There are at least 5 (probably not much more) litres of fresh fuel in the car, I can smell the fuel coming through for a short while after trying to start it and my mechanic confirmed it was getting through. Do you think there needs to be more in it to fire up? If so how much?

 

alec,

As mentioned, you say that you have a "weak spark", but I'm still not sure what you mean. Do you mean that you actually know that you don't have a strong spark on the spark plug by examning one of them as the engine is turning over and you're actually seeing a weak spark? Or do you just mean that the engine isn't catching?

If you've really got a "weak spark" then I think you still have a wiring, coil or spark plug problem. However, if you just mean that the engine doesn't catch, you have to look further.

- Are you seeing sparks fire properly on a removed earthed plug whilst cranking the engine?
- Are the spark plugs wet with petrol after an abortive start?
- Can you watch petrol spurt from a removed injector whilst cranking the engine?
- Is the engine position sensor correctly installed and aligned?

If you don't know the answer to these, then unfortunately, you're just guessing by changing parts.

Paul

 

Hi Alec

I've got the AJ16 engine in my 1995 XJS and had the same problem starting.

Do you know for certain that fuel is getting through?

Can you hear the fuel pump run when you turn on the ignition?

Did your mechanic crack the fuel pipe union nut in the engine compartment to check that fuel was getting to the fuel rack?

One possibility is the Coolant Temperature Sensor may need replacing, or a worst case scenario, you may need a New Fuel Pump, if it turns out that yours is not working.

On my Car replacing this was the job from 'Hell' as the pump sat in the Top of the fuel tank and in order to replace the pump, the fuel tank had to come out!

Not a job I'd really want to ever do again!

I hope its not that though it could be.

As the fuel pump dips into the fuel, the 5 liters that you mentioned may not be enough for the pump to suck up, when spread all over the bottom of the tank.

So I would definitely put enough fuel in, to have the gauge moving off empty.

 

Thanks for the advice everyone.
Have topped up another 10L of fuel so tank gauge goes to a quarter but still no start.
Have shipped the car off to an XJS expert with Jaguar testing equipment.
Will let you know how it goes!

 

Good luck with that Alec

Please let us know when you find out the cause of the problem

 

Car fixed! Thanks to Paul Hands of Hyper Transformations.
Car servicing for jaguars in Oxford, Garages, Repair service, Bodywork specialists
This experienced expert is based only 7km from my home but I took some googling to find him so put his link here if you ever have an XJS problem and no-one else can solve it.

He diagnosed the problem within a day of getting the car and only charged me 2 hours labour. I don't know what the problem was as he says it's a trade secret(!) but it's basically a cheap component somewhere.

So $600 in parts later (battery over winter for same problem, 6 coils, crankshaft sensor, engine position sensor, ECU) I have now found the only mechanic I ever need for my XJS!

Question now is how much I use my money and his expertise to restore it...

Anyone want to buy a spare AJ16 LHE1410 ECU?!

 

Hi Alec

Just had a bit of an afterthought and I'm thinking Fuel Pump Relay?

 

Alec,

I'm really pleased you've managed to get the car fixed. I do think there's a lesson which is never change a component unless you really have diagnosed that it is at fault.

I have heard good things about Hyper Transformations, however, if I were you, I would demand to know what is the problem that they've found. You've paid good money, so you're absolutely entitled to know what he's done!

Enjoy the car now!

Paul

 

Hi Paul

Totally agree with that, it could have well been something as simple as a fuse!

 

Glad the cars back on and all...but he won't do what????

Maybe it's a cultural thing as I know you are in the United Kingdom, but this is not the Colonels recipe or the codes for the nukes. He needs give you a detailed report of what he did to get the car going....

 

Hi guys and gals

Paul Hands hear thought i would comment on the comments about my not saying what was wrong with the car
we the team at HYPER have been in the trade for some 35 yrs and 25 of that has been on jaguar only we always get the cars that other grages can not sort out etc
so why should we give away all of the knolage that we have ( and a lot of found out the hard way buy making mistakes and trying different things and componets at no charge to the customer because we only charge for the componetthat was wrong unlike most other garages who fit and still charge if it does not fix the problem etc

so i say again that i make no opligies for not telling the world what was the main problem with the car but none of the commenmts after the post where right
we will and always have helped put pepole with problems in the right direction but it is always easier to look at the car / problem on site.

love and peace
to you all

paul hands Hyper

 

Now to be fair, if you knew a little trade secret that could earn you a few shekels for very little work wouldn't you keep it to yourself?
I'm pretty sure I would.
No I wouldn't.
Or would I?
I dunno!

 

Well, if I would be near you, I would never ever go to you if this is your way of doing things.

First of all, I think it's very arrogant to assume you always get the shitty cars. There's tons of people with knowledge of jaguars. This way of handling would rather put you out of business i think.

Second, I am dutch and also visit a dutch jaguar forum. (www.jaguarforum.nl) and there is a guy who owns a jag garage, and always helps people by posting solutions. Result: From the entire country people go to him because of his attitude, and because he shows to know stuff. For all we know now, you just made a lucky guess because this is your first reaction on here.

Finally. Who knows you turned key, didn't hear fuel pump running, and just replaced relay. (or another silly little thing).Took you 5-10 minutes max, and still you charge 2 hours!!! Cause to be honest, if you charge two hours it is most likely you spend less on the car!