That quote to too much before I finish my morning coffee lol
I'll take your word for it.
I had better pull the injector harness I guess.

 

This has had me thinking. Maybe the microswitch that control this is causing my issues.
I'll check it and report back.

 

Eric,

That micro has ZERO to do with that.

It simply earths a circuit in the ECU that richens the fuel by approx 15% for high end running.

The TPS is the trigger for the Injector pulse with the Ign ON and engine OFF.

 

So just noticed I had stated the car is an 1989 actually it is a 1985.

Have to keep my vehicles straight.

Sorry about that

 

I took a few minutes today to look at the car.

Not related to my problem but just to make sure things were proper I checked the throttle “Kick Down” switch and throttle Pulley EFI Micro-switch (for Closed/Open Loop Mode of the EFI). The switch at the pulley was fine but the kick down switch was broken. Changed both for good measure and they are working properly.

I have ordered a new TPS it will be here Thursday so we'll see what that does. I did fiddle with the connector and wires.
Now if the ignition is on and I open the throttle (any amount ) all injectors will fire.






I

 

Probably of no significance in this particular situation. The V12 ignition and fuel injection systems were fundamentally the same for quite a few years. There were various detail differences by year or market.....but we'll stay out of that minefield unless forced to enter.

Cheers
DD

 

Don't be the least bit surprised if you come across more fiddly wires. Age and heat takes a toll and decrepit wiring causes all manner of gremlins on these cars.

If time and opportunity allows, and the spirit is willing, I suggest "doing the Vee". That is, remove the intake manifolds and other 'stuff' to get right into the Vee of the engine....to rebuild the injector wiring harness, replace vacuum hoses, repair/replace any cooked wiring, replace cam cover gaskets, replace plugs, wires, and cap, replace oil switch and sender, etc. It's a very rare V12 that isn't suffering in this area. You'll be preemptively solving problems. Do it all, do it right, do it once. The alá carte approach to fixing this stuff is much more difficult.

Cheers
DD

 

Willing spirit but unfortunately that will have to wait until I finish building my house. Definitely high on my things to do list.

 

I had some time so I pulled the fuel injection harness and replaced all the wires and a couple suspect looking injector plugs. Ran the new harness up by the fuel rail.
Upon starting the Jaguar sounded much healthier. Took it for a 20 minute drive and all was well. Stopped back home for a half hour when I went to toke it for a another test drive it started acting up again.

DRATS...or maybe I used a couple other expletives.

Later I'll order all new silicone wires are injector plugs and make a good harness but this one will do fine for a couple months. I hope.

A new TPS showed up at the house today so that is the next step. I think I will also change the entire length of shielded wire that runs from the ignition AMP to pin 18 on ECU.

I'm also going to swap out the ignition amplifier.

Fingers crossed

 

Installed new:
Ford TPS with new connector. Voltage reading at full throttle is only 4V so i think it my be faulty but idle reads proper and for the moment it is better than the 3V closed and 4.3V open I was getting with my old one.
Did not cure the issue unfortunately. When the car does run it sounds much healthier though but randomly it will die. When it does the fuel pump keeps running and now the fuel injectors keep firing.

So I swapped out the ignition module with a new GM one. No change.

Checked the ignition modules trigger wire again when the problem is happening.
Continuity was fine to pim 18 at ECU and there was no continuity to ground.

ECU pins and connectors are clean and look fine

So now I'm done.

Think it may be ECU but what is killing them since my old one does the same thing? Opened it up but could not see any buring or loose solder joints. Pluged it in and pushed and wiggled all I could on the board but the problem persisted.

 

Update.

I checked to see if the coil is firing when the car is acting up an it does not. Even though all the injectors are clicking away and fuel pump is running.

Also just noticed that my tach stopped working after I replaced the GM ignition module and removed the capacitor from the box (read it can cause issues). Not sure if it is related to my issue or the wire lost connection. I will check into it.

 

Oops.

Tacho drop is more than likely the feed wire from the module. The White with the Spiral Slate/Blue trace. The next can also be at play.

The coil dropping out is "usually" a signal issue, either FROM that module, or its wiring, or the paste layer between it and the casing, causing that module to get HOT and breakdown.

Then there is the 12v supply FROM the Ign switch, well documented as a problem area now, due to age. A simply dismantle and clean does wonders.

A voltmeter on the +ve of the coil, and note the behaviour when the engine plays up, it should be 12v ish ALL the time.

Of course, dud modules out of the box are now getting common, sadly.

Engine earth strap integrity, or lack of, is also a major issue, mainly with the V12. Run a seperate GOOD earth cable, engine direct to chassis. Sorted many odd electricekeryissues for me over the years.

 

Picked up a used ECU DAC6337. Installed it and the issue of the pump and fuel injectors running has not yet returned.

I do have a new issue with the engine missing or not receiving enough fuel passed about half throttle. Part thottle it drves fine. I am going to swap the old ignition module see what happens.
Hoping my new module is just a dud and tac and hesitating go away.

Still haven't had a chance to add an engine ground but I will do that shortly.