Dear all,
My name is Val and im new to the forum, however i know it since it helped me alot so far so I have the following case:
I bought an old jag with 322.000kms that i liked for quiet cheap as a project car to learn. It was parked outside for a few years. It wasnt starting when i bought it. I manage to get it working and now we have the 5th and 6th cylinders not working. Since i dont have the proper mechanic education i started from upside down and i checked the electronic side of it (im not an electrician either) The professional electrician found some problems in 2 amplifiers for the coils (changed them all 12 new) and 2 amplifiers of the injector signals (changed them all 6 new). Then i got the cylinder compression test all seemed to be in order since before that had the head gasket changed and a valve job myself. I was searching quiet alot for standard piston rings once i had it all open however never found anywhere. The car starts and runs poor. However now it got to Limp mode and drive only of 3rd (as i red here). I had the Trasnmission ecu checked and it has no problems so i didnt change it and i hoped the car switched to safe mode since 2 cylinders doesnt go. Now i will check the gasoline compression in order to know is it 4bars or less...right? I also notice oil coming out of the outlet manifold exactly where the 5th and 6th cylinders are. Any ideas are welcome

Ps: i notice the cylinders does not work when i changed the coils 4 5 6 with 1 2 3 and the spark plugs are all 6 new. With the engine running when i lift the coil of the 5th and 6th cyl it has no change and when i lift the rest it looses power.
Tomorrow will attach pictures and a video is possible
i love this car and i will get it running nomatter what
Thanks to all in advance

 

Val:
I realize English is probably not your primary language, but it is somewhat difficult to understand your question because some things do not "add up" or make sense.

1. What "amplifiers" for the coils? We are talking about a model year 1997, 6 cylinder Jaguar XJR, right? As far as I know there are no amplifiers external to the ECU, and certainly not 12 of them, so I have no idea what you mean. Please explain.
2. Same with the "amplifiers" for the injectors. What part do you mean?
3. It is very important to get the cylinder compression reading for the next step.

Another long shot. The 5th and 6th ignition coil connectors can be swapped. The one for coil 6 usually has a marker for identification. Check this picture for the yellow marker on the #6 coil wire.

 

Dear Sparkenzap,

I was so excited writing it that my thoughts went faster than my writing and now that i read it, it does not make sense to me either
Sorry for that
Reply to your questions:
1. In the ECM there are coil signal apmlifiers called IRFR120, there are 2 on each coil a total of 12 piece. Yes, it is a 1995 XJR 4.0 Supercharged
2. In the ECM there are injector signal amplifiers called Darlington Motorola BU323Z, there is 1 on each injector.
3. The cylinder compression test is done and it is 9kgs on each one, which i suppose is good.

And now, I just switched the 5h and 6th coil harness and it was exactly why they didnt work However i dont understand why they did it like this, doesnt make sense the last coil to be upside down. Now everything seems working

A LOT OF THANKS SPARKENZAP!!!!!!!!!!!!!!!!!!!

The last issue i have is this LIMP mode. How can i get the car out of it?

Its a great car gosh i love it even more

 

Congratulations! I am sure you will enjoy driving this car. And, it did not even occur to me that you were inside the ECU. Keep track of that electrician, he seems to know his stuff.

Now, as to the Limp. Get the OBD codes read with an OBD scanner. If you need help figuring out how to do that, check back.

 

Hello yes i just scanned and no error codes stores. I dont understand. I still have the cooling water red light on however i bought a second hand working sensor from ebay uk quality shop and still the same. Will attach pic now

 

I suppose theupper left is the limpmode lamp and the down right, above the airbag is the red coolant sensor lamp which did not go away once i changed it

 

Hmmh. It looks like every warning is on! I wonder what zapped your ECU? They seldom fail the output amplifier transistors, so I wonder if your got reverse voltage at some point? I would say it is time to get it connected to AutoEnginuity or the dealer level software like IDS, WDS, or AutoLogic and start running down each indication until you decide the ECU is bad. Or, with luck, a bad engine ground strap!

 

Thats what i was thinking also to get it checked at the dealer. Unfortunately I dont know anybody in the zone to have those softwares besides the dealer. The ecu amplifier transistors are exactly the ones changed now so at least thats a good sign.
do u think i need to get the abs module to my electrician to check it?

 

Check the connector to the transmission and the transmission mount. The wires leading to the transmission are very short and can be broken if the transmission mount is worn out. Which it most likely is. The GM transmission in these cars are very robust.

 

On a vibration inspection i noticed the trasnmission mount was worn out so i decided to invent a new rubber mount in stead of the old expensive two springs the dealer has. I will send a picture later on and explanation. So there is a fat cable going from the stick directly to the gearbox and it is pretty distroyed. Maybe this is the problem? Thanks in advance guys

 

Good chance! The engine and transmission communicate on a bus. Get that fixed and you are one step closer! Boy, the previous owner let bad things happen to this car!

 

thanks guys I also found a few other problem related:
1. When i accelerate the rev pointer goes up to 2000 and then suddenly drops to 0 and when i come lower to 2000 then it marks it again. Any ideas or its jus the limp mode thing?
2. The linear switch of the of the gear change control was all in grease. It is an electrical and i dont think it should be covered with grease. I cleaned and put back on.
3. Judging by the picture up this is the gearbox control cable. It is not electrical so this outside breaking should not affect the performance. Correct me if im wrong.

Tomorrow will inspect the gearbox fuse and relay and the gearbox harness (by knightofgold advice)

 

1. It sounds like a new CKPS might be needed. They are hard to bench test and not very expensive. That alone could cause many of your issues.
2. Yes, sounds good
3, It looks to me like a frayed conductor is hanging out, but you ar elooking at it and I am not!

 

Knightofgold do u know is this harness where connects to the transmission is on a screw base or just push base? It looks to me like screw/unscrew however i dont want to break anything anymore os should i just pull it?

 

1.I will try first the connector to the transmission and then will see if problem with the revs persis
3.i believe t is just the metal strings protection that is damaged. I will cover it thats for sure

 

The coolant light that is shown on earlier in this post, is for the coolant level sensor in the header tank. Is this the sensor that you replaced with a part from ebay. This part should not be confused with either the coolant temperature sensor for the instrument pack or the coolant temperature sensor for the engine ECU.


PS Did someone really replace the ignition coil and injector driver circuits inside your engine ECU. These components are not intended to be replaced, and I have NEVER heard of them failing. If you are ever 100% convinced that there is a fault with an ECU then I would just recommend getting a replacement ECU from a scrap car. I would never recommend taking a soldering iron to an engine ECU, but good luck to you if it still works. Such a modification would be very specialist work indeed.

 

Good evening, thanks for the reply.
For the cooland light problem is exactly the sensor that i bought from second hand uk dealer that asured its working, however nothing changed.

I have the ecu to a special electritian that do thise kind of things and he found the not correct signals coming out of the amplified transistors on the 5th and 6th coil and same with 5th and 6th injectors. The purpose why i gave it to him was exactly because of my amateur expertise with the Ohms meter and little light detected some strange values on those 2 coils and injectors. After i switched th 2 coil cables the car got silent and powerful and here comes the best part: the guy charged me 80eur for the 6 transistors for the injectors and 50eur for the 12 amplifiers for the coils plus the cost of them which was approx 43eur form ebay

 

Yeah, cheap enough but it looks like your ecu may still have problems!

 

That looks like your transmission wire harness. These transmissions are electronically controlled and you need to repair it to get your transmission working. To access the transmission electrical plug, you will need to lower the transmission a little by unbolting the transmission mount. This should put the harness plug within reach. It just pulls off if I remember right.

 

Thanks knightofgold i got it all taped out however this is the gearbox control cable that does not have electricity on it and those are the protection fat metal wires here is a pic


I just Ohms checked the gearbox electrical harness from the gearbox underneath the car up to the TCM and it has no problems. However this s what i found inside the TCM



And it looks pretty frayed to me. I send it to my electrician right away.
I will keep you posted thanks guys!!!