1992 XJS V12 with Marelli – Injector Issues (No Hoses)

Hi Forum,

It’s been over 2 years since I started trying to get this car running smoothly. From the day I bought it, it had a misfire when hot. Since the engine bay wasn’t in the best condition, I overhauled it completely, thinking that one of those things would fix the issue.

Spark plugs, fuel rail, pump, filters, crank sensors, O2 sensors—all sensors, actually. I even rewired the harness, etc. Basically, everything around the engine has been checked.

The injectors were cleaned and inspected at a shop.

Long story short:

Now, my friend's garage and I have taken the issue seriously, and everyone agrees it's the injectors on Bank A.

The car runs smoothly when cold, so we tested the injectors cold by letting them spray into caps—everything seemed fine and equal. But once we brought the engine up to normal temperature, four injectors were clearly over-spraying, and badly.

Funny thing is, about 6 months ago I tried to find 6 new injectors just to eliminate that area as a problem. I only managed to get 4 from a UK site that sells refurbished ones—paid £200 for them.

Guess what? None of the 4 worked at all.

I honestly don’t know what to do now. Can someone advise where I can find 4–5 good injectors? I can’t believe these injectors were used only in the XJS.

The injector code is EBC2409.

If nobody helps me out, I swear I’m setting this car on fire!

P.S please i beg you, dont ask me about TPS adjustments, coils, vacuum lines, clean throttle blade and all that staff, i have been on this forum for 3 years, i know that goddamn book by Kirby by heart!

 

I have 12 refurbs going in this weekend, Rockauto sells them pretty cheap.

 

EBC2409 on rockauto? can you please give me link, i cant find it

 

See post below

 

They have 2 part numbers, long and short hose hut both have the same length hose(product was identical)


note** the pic above was for my lucas car, your 92 doesnt have the hoses so disregard that comment.

 

Apologies
If your car has the cast injector rails and no hoses connecting the injectors to it, then my post above is incorrect. You need this sort
https://www.injectorplanet.com/produ...guar-ebc2409-1

Rockauto may have them too, but they are not the ones in the lower photo in the post above. These are listed by Rockauto for a 1992 5.3 motor
https://www.rockauto.com/en/moreinfo...lghv%2Filk0%3D

 

The upper picture in my post was indeed the ones he needs, and available through rockauto.

you can search Rockauto using the Jaguar part number(thats how I got that picture).

 

thank you Greg. I bought 4 those injectors from injector planet and weren’t working at all. I will try rockauto! Thank you

 

Good luck. Rockauto will give you your money back if they do not work. I have had four (older type) injectors from them and all good.

 

Hey forum, again need your help, because im stuck now completely.
Got new injectors from Rockauto - same thing , 4 injectors over-spraying when hot

injectors 5,6,10,11
on cold -everything normal
on hot - those 4 injectors start to over spraying by around 7-9% comparing to others

basically once they start to over-spraying you can feel a vibration on the engine and inside the car as well. that might feel like a light missfire.

Thank you

 

I'm not quite clear on this.

Are you saying that you have four faulty injectors?

Or are you saying that the ECU is giving incorrect commands to four injectors?

Not sure which injectors are 5,6,10,11

The injectors are batched like this
2A 4A 6A
2B 4B 6B
1A 3A 5A
1B 3B 5B

All the injectors within a single will receive the same command from the ECU.

Maybe take another look at the harness? Or take a careful look at the ECU pins?

Cheers
DD

 

Thats the question, i know that ECU cant give separate commands to 4 injectors, as far as i know injectors are being controlled in a set of 3, or even 6
But yes, 4 injectors seems like over-spraying

Sorry for my injector numbering
i meant its 5a, 6a , 4B, 5B

ECU is out, since i have a spare one and it does same thing

 

Not sure I get what is going on here.
The information below shows the injector sequence. I made this a long time ago to check something when fitting an aftermarket EFI system.
There is a note that group 1 and group 2 fire together, and 3 and 4 also together.

1) How do you know any particular injector is spraying too much fuel ?
What is the test method ?
The only one I can think of is to check the energisation time with an oscilloscope compared with the average of most "good" injectors with engine running.
You can by a basic 2 channel oscilloscope to check this for peanuts nowadays. Quick before the tariffs hike the price.
2) If 5A, 6A, 4B, 5B are truly spraying too much fuel that is a strange combination.
It does not line up with the wiring of the injector groups.
3) If statement 2) is correct it indicates:
a) The wiring of injectors is not correct, or there is a mechanical fault in those 4 injectors.
b) Or both the wiring is not correct and the ECU is driving those 4 injectors for too long.

4) If the injector harness has been rewired as mentioned earlier, good idea to double check it.
5) The fact that the fault only happens after the engine warms up is another puzzle.
Injectors will tolerate a fair bit of heat. I would suspect the ECU warming up to be more likely to explain this.
SOP to check this is apply an ice pack to the ECU to see if that cures the problem.
On the other hand the ECU was swapped with another, but I would still ice pack it to eliminate the possibility.
On the off chance something is screwed up in the resistor pack give that an ice pack treatment.
6) First thing to solve the puzzle is to find what item warming up creates the apparent over fuelling.
The chances of it being the 4 injectors is remote. If they are faulty they are 99.9% sure to be faulty hot or cold.

Good luck with tracking down the problem, it is one of the more unusual ones to come across.