I'll have to remember that one!

 

"Giggles" now that needs a STICKY.

You have life i the beast.

Had a thought at about 3AM,. It sounds like its trying to start on a too lean a mixture for a cold stored engine.

Remove your bridge from the CTS, replug the loom to that sensor. That will inform the ECU the engine is COLD. That bridge "fools' the ECU to thinking the engine is HOT, thus a very lean fuel dose.

It may take coaxing, and a squirt of Ether here and there, to get it up and running, but I reckon it 95% there.

GOOD WORK JP.

 

Hi Grant
I tried something yesterday. I check on my xj6 the strenght of the spark going to the spark plug and it gave me a strong bluish spark. I then tried it on the V12 and the spark is very small yellowish. Not the same at all. I think that my problem lies with the fire.
I notice the distributor cap is damaged, there is a piece broken. The previous guy who work on it probably failed to remove one of the three screws and snaped the section at the base of the distributor so there is a hole there. Could this screw up the strenght of the spark? I check both coil and they looks in good condition. What else could impede the spark?
I believe that the gas goes to the spark plug now because I small gas fume coming out of the exhaust.
thanks

 

Renew the cap, that is for sure. In your place I would renew the coils, the rotor and the amp and have done with it!

 

I have already ordered new cap last week. Will be here next week. I have already changed the amplifier. I will replace the coils.
Thanks

 

Agreed at this point with Greg.

Coils could be OK, but they are NOT expensive, and as Greg said "be done with them", repeat in 30 years.

While waiting, take a look at the engine strap fiasco around the B Bank engine mount brackets. British Engineering at its best. Remove them, CLEAN them both, ensure that you have:
Engine to Cradle
Crale to chassis.

Then, another dedicated earth cable, engine to chassis. Anywhere convenient. I use a sump bolt on the B Bank side, back near the oil filter, and go across to a chassis mount bolt just there.

Too many earths, you will NEVER have too many earths on a V12.

 

Good plan. My car was running and starting perfectly, but its hot starting was not instantaneous. I had a new set of coils in stock, and a new dizzy pickup, so I fitted them. I was astonished that the car ran significantly better afterwards! even though it seemed to be perfect beforehand. New bits in the ignition are a great idea!

 

Hi Grant,
I took some time off the last few days.
I received my my distributing cap and intalled it. Still waiting for my 2 coils to come in
Couple of issues:

• Now the fuel pump does not turn when the ignition is on. The pump works well but there is not power going to it. Fuel pump relay probably. I ll look into it.
• Tried to start the engine. When I disconnect the main lead which come from the coil at the distributor, i hold it close to the engine and there is a strong arching, which tells me that the coils are working and there are power going to the distributor. I even got a shock right to the elbow!
• There is also a good spark at the end of the lead going to th espark plugs.
• I used the quick start with no success. Couple of inlet back fire.

In short, I have the gas going to the injectors (35-40lbs) , there is spark at the park plugs, the injector seems to be working. The only thing I have not checked is to ensure the timing is ok. Whoever worked on the car may have timed the engine with the piston 1A at bottom center instead of Top dead center. I guess to check this I ll have to dislodge the AC compressor so I can access the piston 1A spark plug. Thought job.
Once I check the timing and install the new coils I will be out of solution, let s hope it going to work!

 

JP.

Fuel pump relay, maybe. Check. and even reset, the Inertia Switch, on the A Pillar RH side on our cars, just near the drivers Right knee. Yours may be on the other side, dunno.

Spark jolt to the elbow is GOOD. Its a bonding thing between the car and you, fact.

If the A/C is a pain, maybe this Aussie cheats way will help you.

Make a mark on the distributor cap for 3A spark plug wire, then copy that to the distributor casing, so it can be read when the cap is off.
Remove 3A spark plug. Do the HAND rotation as per my PDF, using something to plug the hole, so you can feel the air rush as the piston rises on the Comp stroke. A probe (opened out wire coathanger is good, down the hole.
HAND rotate SLOWLY, and when the wire STOPS rising, STOP rotating.
Look at the rotor pointer, and the mark you made. Do they lined up?. If so, the engine is timed correctly mechanically.

Then double check the plug leads in the cap. I have goofed up here many times, so it is something to never be afraid of checking, just to be sure.

1A 6B 5A 2B 3A 4B 6A 1B 2A 5B 4A 3B

Anti Clockwise as looking down at the top of the cap.

Lets know the outcome.

Many more ideas once these basics are sorted.

 

Hi Grant finally the baby is running!!!! The problem was simple: I rotate the leads the wrong direction. 😞 re installed them and the motor started immediately.
Two problems remain though:

• the engine idles way to fast around 1800 RPM. Will need help on how to adjust it.
• Secondly, the fuel pump does not Turner with the ignition. I have to run a wire from a power source to the pump. I did a continuité test from the relay to the pump and it s ok.
• There is also a problem with the brake as it seems that the front calipers don t release the pressure. I may have to replace them.

I must say that I am quite encouraged by the Progress.
feel free to share more of that rare k owlwedge of yours !
Cheers

 

AHA, my trick, so you know you are NOT alone. I blame old age and one eye, HA>

I am impressed, you have done the quiet systematic diagnosis.

I will sort some Doco's later, when II finish some concrete repairs.

That idle will be simple, and once again, the systematic approach will win out.

Back soon.

 

OK, got rained out, bugga.

That engine is going to take a good while to settle down, so be patient, and ONE thing at a time.

When sorted a good hard run, say Vegas and back, will be the BEST you can do, for the car and YOU. Luv Vegas.

The COLD idle is generally around 1200ish RPM, and settles as the engine travels toward Normal Temp.

Some markets have a 15 minute timer, that raises revs stupidly, no idea for yours.

The AAV, Throttle Discs, Throttle Rods, ALL need to checked for true, as that Freddie Fiddler has been in there.

Vac leaks, there will be for sure. ONE hose at a time, replace them all. Dont rip them all out at once, as schematics for Vac hose layout are basically non existent, and vague at best, if found.

Check the 24 nuts that secure the Inlet manifolds to the heads. They can loosen, and vac leaks will occur. NOT stupid tight, just nice and firm.

The 90deg rubber elbow stupidity on top of the AAV is a classic leaker, so get a NEW one before you start on that sucker.

The attachments run through the system. If there is something unclear, ask, and we will sort it simply.

 

Thanks Grant we will be patient and check them one at the time. Cheers

 

I am not familiar with the V12 EFI system, but on the straight 6 version the fuel pump only runs either when cranking or when the AFM detects airflow through to the throttle body. If you take off the air filter and manually open the flap in the AFM, that should energise the relay and make the pump run.

 

The fuel pump circuit (and fuel injection system) is substantially different on the V12, Andy

Cheers
DD

 

This is Excellent advice no matter what you're working on!
Even if it's only a common, ordinary old, run-of-the-mill Chevy 350 which are Well documented!
(I can tell you how I know that, but I was young and stupid then)
(';')

 

YUP whenever I swap spark plug wires, it is one at a time.

1. well, not aways. I swapped all of them in my LT1 powered XJ. It is really fun. Done from down under. And all eith pass through ocluded space. Done by feel!! Yahoo, i got them right it fired right up.

Decadesago circa 58. I fired up my buildt from scratch using junk parts. T speedster. it ran on three??? On a hunch,I swapeed two and three!!!. All four nowlll why: i have a fuzzy hunchl. More than merel in the wrong places....

 

We have all been there! It is a V12 rite of passage!

 

Hi Grant, as thing were going well as I started the Jag for the first time. Yesterday I adjusted the throttle vavle to 0.0002 inch as per recommended, and today the car won t even start. When I turn the ignition, the fuel pump does not turn anymore, and the injector dont click anymore. I ran a wire to the fuel line and the pump is working well and the pressure going to the injector is at 36 psi so that is not a fuel pump issue. I checked the main relay which is supposed to send power to the fuel pump and other place. There is a "click" inside but when I check with a light the other prong, there is no power going to any of them and no power going to the fuel pump. Can the main relay be faulty? I read that the main relay send signal to both the injectors and fuel pump via the ECU. I am looking at buying couple of main relays
Do you have suggestion as to how to disgnose these relays? Do you have the part number of these two relays? I think there one the last digit is 113. Is this the main of the fuel relay?
thanks again..

 

JP

The Main Relay "Turns on" many things. Mainly the ECU and the Fuel Pump Relay.
The Main relay is a standard Cube 5 pin relay, with a Diode. The MAIN thing to watch for is the relay has 2 X #87 terminals, NO, repeat NO 87a pr 87b, as they will reek more havoc than needed. I dont use Diode relays, and I am happy with MY decision, your car, your call.

The Fuel Pump relay is also a standard Cube 5 pin relay, or even a 4 pin, as the centre #87 is not connected on that Black Socket.

When inserting those relays PAY ATTENTION to the Socket wires, as they are known to :
"push out" as the relay is pushed IN, OOPS.

Find the Inertia Switch, inside the car. Ours are on the RH "A" Pillar, near the drivers Right knee. They can cause issues. Soooooo, for now, simply join the 2 wires, until the car is sorted, then fiddle with that sucker.

Also, the Pump relay Orange wire. Splice a new wire into it and Earth that wire. This by-passes the ECU Pump Relay Earth Circuit (known issue on some), and for this sorting procedure, a good idea in my opinion. The ECU "may" be having Timer circuit earth issues, and frustrating you.

Dont know Part numbers, never purchased a Jaguar relay in 55 years, always Bosch, Narva, etc. I can supply those numbers later if you need, as I will look them up.