Hey guy back again. So I was driving the car at highway speeds. When I went park the car it started misfiring. Things that checked and errors below

Checked
Coils
Spark plugs
Fuel pressure
Vacuum leaks

​​​​​​These all above are fine

​​​​​Errors
coils cylinder (b,d,f,h)

Sometimes it gives error for throttle body.

Any ideas will be appreciated

 

Your description reminds me of when one of the HPFPs in our XJ failed.
Search existing posts for HPFP, and you will find much descriptive info that won't be re-written here.
AND since it already exists in previous posts, you don't have to wait for replies to your questions - they've already been asked & answered.

 

@Abbas_ahmd, kindly provide some background information:

• Vehicle MY
• Current kilometres/miles showing on the odometer
• Is the MIL on, and if so what DTCs are stored?
• What is the fuel pressure during the misfire event(s)?
• What is the ambient temperature during the misfire event(s)?

DO NOT continue to operate the engine under any conditions that cause the MIL to flash as catalyst damage is occurring.

 

Even with new coils still codes are there

 

Based on my personal experience with the AJ133/126, the ignition coils are very rarely the problem.

When all the misfires are on one cylinder bank (Bank2), check the wiring loom and connectors for damage. It may also be necessary to perform a pin test for continuity from the Engine Control Module (ECM) to the injectors.

 

Thank you for the reply I don't know how to perform the pin test please guide on it. Wiring looks fine.

 

Where is the vehicle located? Is there water puddled anywhere inside the vehicle?

Pin test requires using an ohmmeter to check the wiring from the ECM to the injectors to determine resistance and if there is an open circuit. The ECM provides the earth (ground) for the injectors.

 

Here is a link to the AJ133/AJ126 Training Course:

https://www.dropbox.com/s/k214bnpsi2...ining.pdf?dl=0

Here is a link to the X351 Workshop Manual:

https://www.dropbox.com/s/jife7kkbcl..._2014.pdf?dl=0

Refer to page 7454 of the Workshop Manual for DTC explanations.

Here is a link to the Electrical Diagrams file:

https://www.dropbox.com/s/6zseatxlrc...22231.pdf?dl=0

Refer to section 310-01 (page 63) for Fuel Tank & Lines schematic diagrams.

 

Wow NBCAT. Above and beyond with the help and support! This is why this forum is awesome.

 

Thank you thank you thank you so much for these. Will be really helpful. Today we are going to test the fuel pump and injectors. Got an aj133 out of range rover available for parts will test all the things. Will see how it goes

 

So changed the coils that came off from the engine it is much better then before but still misfires search continues......

 

Thanks for the updates. Please keep us posted on your progress.

 

Update

Coils changed
Injectors changed
Plugs changed

Still same issue as it warms up starts to misfire

Am really stuck on this now

just don't want to keep putting the money on it like this

Remaining I guess is fuel pump and throttle

In last will check the timing

As cold starts are fine till it reach the middle temperature niddle

My guess is throttle body

As when warmed up the car starts to misfire on idle maybe the position sensor is acting up

Other idea is hpfp but then it should not do this on cold start

By cold start mean the car is in Dubai and weather is very hot here so its not like really a cold start and car gets to running temp really fast.

In the last I think of timing but if timing was out it shouldn't be fine on the cold start

 

Only code which I see scanner are for left bank coils all the time

 

Apparently you did not find and read the posts I wrote on the HPFP failure on my wife's XJ.
Good luck with finding the cause - it looks like it's getting quite expensive & time-consuming.

 

I did find the post gone through it. So here what's happening is that car warms up fine and stabilize for few mints but then suddenly starts misfiring alot with back fires. It's bit confusing for me however I will change the fuel pump now. And btw there is no cat in the car but that shouldn't be causing it as it was running fine.


I will report back after changing the fuel pump

 

If you read through the post -
Have any of you replaced the HPFPs yourself? - Jaguar Forums - Jaguar Enthusiasts Forum
carefully, you would notice that our XJ ran fine UNTIL it warmed-up to operating temperature.
This sounds like what you're describing, and what is confusing you.
However, other characteristics that you're seeing but not describing might be leading you away from an HPFP failure.

And you say you will change "THE" fuel pump.
Which one?
There are THREE fuel pumps in this car.

 

I mean by hpfp when I say fuel pump

 

There are 2 HP cam driven pumps on the engine block and one fuel pump in the gas tank accessed by talking the rear seat bottom out and opening the access panels. FYI

 

OK,

I maybe wrong on this, but here is my understanding of how the AJV8 comes up to operating temp, and what happens afterwards;

The start initiation is pre-programmed, the engine will race to 1250ish rpm, and then, in stages, back down to 650-700.

Once that process is complete, the engine (ECM) will start it's search for CAN BUS data. (Temp, O2, MAF, TP, Gear, Torque demand, etc, etc, etc). If one of those is out, the engine will spit rabbits.

Go for the cheapest things first;

Clean both MAFs (10 mins, $5)
Clean the TB (15 mins $10)

You also mentioned that the car doesn't have Cats, change the downstream O2 sensors, they are either cooked or clogged.

wombat