Hi all. Back story first.
In July I took ownership of a poorly 2008 FL2 TD4 SE. It is in generally nice condition, showing little wear to anything important, and has both keys (I was shocked how few used FL2s have both).
The only issue was it was running on 3 cylinders.
It was obviously down on compression in one cylinder, for which I assumed it was a dropped port flap.
Long story short, it was actually a nut in the combustion chamber, where the person doing previous work was careless. 
After many hours work and some replacement parts, the engine is up and running again, with compression on all 4 cylinders.
However it has a regular misfire when starting from cold. After a few minutes, it begins to pick up on the missing cylinder, where by the time the temperature gauge has gone 1/4 way up the engine is running smoothly on all 4.

I suspected an injector (all the injectors appear to be reconditioned), but figured a faulty reconditioned one. I swapped the misfiring injector for a second hand one, then another, and another, still No3 only fires when warm. I then swapped the known working No2 injector with No3, putting the injector from No3, in cylinder No2, however the fault stays in No3 cylinder, although this swap resulted in lots of smoke too. Presumably the smoke was down to a coding incompatibility issue of those two injectors.

With the injectors back in the original positions, the engine runs fine off load when it's warm, although it does have a random misfire when above about 50% load on the road. I replaced the crank sensor, just to eliminate it as the cause, but it made no difference.

I believe that this No3 cylinder issue is the reason the engine has been fitted with reconditioned injectors, the head has also been replaced, probably right before the nut went into the cylinder, at which point the previous owner got rid of it.

On close inspection of the wiring, I can see evidence of "probing" on the injector harness, so someone has been trying to fix this issue, before making it worse with that nut.

The ECU logs a code if it's started with each injector plug disconnected I know it's not a good plan to do this, but needs must. However every open injector flags an open circuit code, so I assume the wiring to be sound.

So I'm wondering if anyone has had a similar issue. Maybe misfiring when cold, and what was the fix?

Any help at this point will be helpful.

Cheers. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Last edited by Nodge68 on 17th Nov 2020 2:10 pm. Edited 1 time in total

If you get hold of a second hand engine ECU, try to swap and see if it's the same.
Take into account that it may be a laborious thing, because immo information and injector programming is a must, but you will eliminate that too.
I've seen ECUs behave that way, because of poor soldering.
Vibrations and temperature variations are not good friends with factory mass soldering and micro fissures appear during time.
When the inside ECU temperature rises, the dilatation will solve the imperfect contact and all is OK.

Hi Nodge,
I've read through your thread on this over on Landyzone and I came to the conclusion that it is most likely a fault with the engine ECU - either a dry soldered joint or a faulty drive transistor for injector no.3.
The first thing I would try is to remove the ECU and warm it with a hot air gun then refit it and start the engine from cold. If it runs on all four you can then be confident that the fault lies there.
If you decide to try a replacement ECU it is possible to reprogram it with a copy of your firmware but it requires the case to come apart anyway and someone who knows what they are doing so you might as well inspect the PCB on yours to see if it does just need re-soldering.
Cheers, Peter

alex_pescaru wrote:

If you get hold of a second hand engine ECU, try to swap and see if it's the same.
Take into account that it may be a laborious thing, because immo information and injector programming is a must, but you will eliminate that too.
I've seen ECUs behave that way, because of poor soldering.
Vibrations and temperature variations are not good friends with factory mass soldering and micro fissures appear during time.
When the inside ECU temperature rises, the dilatation will solve the imperfect contact and all is OK.

petero wrote:

Hi Nodge,
I've read through your thread on this over on Landyzone and I came to the conclusion that it is most likely a fault with the engine ECU - either a dry soldered joint or a faulty drive transistor for injector no.3.
The first thing I would try is to remove the ECU and warm it with a hot air gun then refit it and start the engine from cold. If it runs on all four you can then be confident that the fault lies there.
If you decide to try a replacement ECU it is possible to reprogram it with a copy of your firmware but it requires the case to come apart anyway and someone who knows what they are doing so you might as well inspect the PCB on yours to see if it does just need re-soldering.
Cheers, Peter

You've done an amazing job to get as far as you have with it so it will be brilliant if you can finally sort it.
If you plug another ECU in it will probably start the engine and then almost immediately cut out as the system realizes that it isn't the correct ECU. It is possible to read the software from yours and rewrite it into another one but it has to be done by someone with the correct equipment and the knowledge of how to sort out the checksum that tells the car all is well. I don't know how to do it but I have a friend who does. Reading and writing to the EPROM involves opening the case and connecting to some pads on the PCB - not for the fainthearted!
Fingers crossed that it's just a dry joint

There is a specific procedure in the dealer SDD software for replacing engine ECU.
It's a simple, step by step procedure, during which it will read the info from the old ECU, have you exchange the ECUs and then write it back to the new ECU.

petero wrote:

You've done an amazing job to get as far as you have with it so it will be brilliant if you can finally sort it.

petero wrote:

If you plug another ECU in it will probably start the engine and then almost immediately cut out as the system realizes that it isn't the correct ECU. It is possible to read the software from yours and rewrite it into another one but it has to be done by someone with the correct equipment and the knowledge of how to sort out the checksum that tells the car all is well. I don't know how to do it but I have a friend who does. Reading and writing to the EPROM involves opening the case and connecting to some pads on the PCB - not for the fainthearted!
Fingers crossed that it's just a dry joint

alex_pescaru wrote:

There is a specific procedure in the dealer SDD software for replacing engine ECU.
It's a simple, step by step procedure, during which it will read the info from the old ECU, have you exchange the ECUs and then write it back to the new ECU.

Thanks for that Alex, it's good to know - the conversation I had with my friend was around remapping the ECU. Is it possible to replace the instrument console in the same way? (apologies for the hijack Nodge!)

Nodge, I use a Mongoose clone lead with JLR SDD V.130 running on a Windows XP virtual machine. The most adventurous thing I have used it for was activating my tow bar electrics! If you search Google you should find some good information on how to set it up and use it - I seem to recall the Jaguar forums were a good source. I believe that if you go newer than V.130 you start to lose functionality - others will know more about this than I do.

Cheers, Peter

You will find some stuff on JLR SDD if you search on here and there is some Jaguar stuff here: https://www.jaguarforum.com/archive/index.php/t-75260.html
and here: https://www.jaguarforum.com/showthread.php?t=108460
If you are able to get it set up and running you will have hours of fun!

petero wrote:

Thanks for that Alex, it's good to know - the conversation I had with my friend was around remapping the ECU. Is it possible to replace the instrument console in the same way? (apologies for the hijack Nodge!)

Nodge, I use a Mongoose clone lead with JLR SDD V.130 running on a Windows XP virtual machine. The most adventurous thing I have used it for was activating my tow bar electrics! If you search Google you should find some good information on how to set it up and use it - I seem to recall the Jaguar forums were a good source. I believe that if you go newer than V.130 you start to lose functionality - others will know more about this than I do.

Cheers, Peter

petero wrote:

Hi Nodge,
The first thing I would try is to remove the ECU and warm it with a hot air gun then refit it and start the engine from cold. If it runs on all four you can then be confident that the fault lies there.
If you decide to try a replacement ECU it is possible to reprogram it with a copy of your firmware but it requires the case to come apart anyway and someone who knows what they are doing so you might as well inspect the PCB on yours to see if it does just need re-soldering.
Cheers, Peter

I can't vouch for this seller but they list a Mongoose clone for £31 here: https://www.cartool.co.uk/wholesale/v159-j...mMQAvD_BwE

It will come with the SDD software and you can also download different versions on one of the Jaguar forum links I posted before.

I can't see the cheap cables on eBay now so it looks like you may have to buy direct from China.

Can you post the part number of your ECU or a photograph of the label on it? I might have a spare one I can let you have to try but it is probably best to make sure that you use an identical one to yours. I will try and dig it out so I know which number mine is.

Thanks Peter. I've ordered one of those.

I'll get the numbers off my EDC, I don't know why I didn't take a picture of it last weekend, while it was on my workshop bench, as I took pictures of the circuit board.

I'll get it out again, and get the numbers, as I'd need those even if I need to order one from ebay.

Thanks for your help. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.