Remember, the ECU is a FUELING ECU, and has ZERO to do with spark or lack of.

Lack of spark generation will render that ECU unable to fire the Injectors, thats all. A Tacho style signal is sent TO the ECU Pin #18 FROM the Ignition system, and thats the only communication they have.

 

Thanks for clarifying.
much appreciated.

 

Hi Grant,
I did a series of test to find out where the missing is.
I will do couple more today.
Test 1 the batterie is fine.
Test 2 Will do today
Test 3 Voltage on main coil is at 11.80 volt
Test 4 Clarification - Must I ground the other wire of the testing device ?
Test 5 Distributor pick up reads 3.65K
Test 6 Will do today.

 

Hi I completed the electrical testing and found out that some wires were crisscrossed. All good now I have sparks going to the spark plugs..
However, when I start the engine, the fuel pump does not operate. I checked the voltage and there is no power going to the pump.
Would you know what could be the cause? Ignition switch? Is there a fuel pump relay?
thanks,

 

Goodo.

Yes, there is a Fuel Pump Relay. I dont know where it is on a Series car, Doug will know when he wakes up.

When you find it, look at the socket, there is an Orange wire. This goes to a timing thingy inside the ECU, and Earths that relay.
When testing, as you are doing, I ALWAYS earth that wire separately and this enables the fuel pump to run whenever the Ign is in the ON position, SO BE CAREFUL PLEASE.

The other thing you need to trace out is the Shielded wire. This runs from that AB14 Amp to Pin #18 of the ECU. They FAIL, often. When this happens, the ECU does NOT fire the Injectors, OR keep the pump running past the 2 second timer phase. It supplies a signal to the ECU that there is Ignition activation up front, so best we do our thing. NO signal, NO Injectors or Fuel Pump.

A simple Ohms test, ECU Pin #18 (ECU unplugged), and the other end at the AB14 Amp. If that is OK, its good to go.

 

OK I will try this today.
I checked the fuel pressure at both the pump and at the regulator. There is not much pressure at the regulator and the at the pump the pressure is about 15-20 lbs only. I suspect the pump needs to be changed. Does it make sense? thanks.

 

As much sense as COLD beer.

Those pumps are 130psi dead ended.
At the FPR, B bank, between the rail and the FPR, should be 41ish engine off. The RH FPR is NOT a pressure regulator and can be eliminated. I have a PDF on that if you want it. They can/do cause lots of odd running issues.

I would get a new one, NOT specific to Jag in any way. Standard 1/2" Inlet with a 5/16" Hi Pressure outlet. GM, Ford, Merc, BMW, etc, etc all used this pump.

NEW fuel filter. Then a spare fuel filter for 3 months time.

Check the fuel supply lines from each tank are clean and flow well by gravity. Fuel spillage will be taking place, so please take care.

 

Hi Grant, I change the fuel pump. Now it is reading over 60 lbs at the pump output.
I tried to start the car . There is spark going to the spark plug but the engine does not start. I checked a aprk plug and it is dry, no trace of gas on it. I suspect the the injector does not function.
I will do a Ohn check like you suggestes between the ECU pin 18 and the Amplifier. Which one is pin 18 on the ECU connector? do you have a diagram?
Couple of questions; pardon my ignorance as I am Fench, I dont undestand the meaning of the acronyms in your text: " At the FPR, B bank, between the rail and the FPR, should be 41ish engine off. The RH FOR is NOT a pressure regulator and can be eliminated. I have a PDF on that if you want it. They can/do cause lots of odd running issues.
​​​​​​​thanks,

 

OOPS, too much Aussie speak.

Ihave edited that FOR, to read FPR.

FPR = Fuel Pressure Regulator.
B Bank = LH side
A Bank = RH side.
Right Hand and Left Hand is ALWAYS noted as sitting in the car facing the front.
AB14 = Ignition Amplifier, bolted to the B Bank Inlet manifold, Black Box is another fitting description.

Look at the fuel rail, there is a short hose incorporated in a metal line, that runs from the rail outlet TO the Inlet of the B Bank FPR. This is the place that actual fuel pressure is taken. It means that hose will be sacrificed, and a simple EFI Spec hose with clamps is the normal replacement.

BUT

You have pressure, and spark, so I would leave that alone for now.
Same with the RH (A Bank) FPR. Lets get it running first, then do the upgrades, less things to worry about.

Some attachments to assist.
There are more, and when I return home (lunch date with wife is a priority), I will sort them and attach.

Keep asking if not sure, thats the name of the game with a V12.

 

Morning from Ontario Canada Grant!
Ok I worked on the car yesterday and here's what I did:

• I put fresh gas in the gas thank.
• Checked the resistance on the amplifier, ok.
• Re-checked the spark plug lead to ensure they are in the right firing order.
• I did a continuity test amplifier and pin 18 all good there!
• Put a new fuel pump
• checked the gas pressure at the fuel rail 35 - 40 lbs ish
• I put the engine on the "on" position and rotated manually the throttle capstan, and as soon as I started to rotate, I hear the Injectors “click”.
• I checked couple of spark plugs, good spark when cranking.
• When I put the ignition on I hear the fuel pump run for a few second then stop. Pump relay is working.
• Reseted the inertia switch.
• I put a short piece of wire to bypassed the CTS (in case it is not working) when I cranked the motor.
• I cranked the engine for 5 or 6 second twice but no start.
• I removed couple of spark plugs and they were dry. no trace of fuel on them.
• I noticed that when I press on the gas pedal when I crank, I hear small back fire nothing strong though.

I have not yet chean the power resistor which I will do today. Can it prevent the injector from working?

Looks like everything is up the snuff except the injectors do not let the gas go through. I know I am getting there though and I am encouraged.

Lastly, I notice couple of vaccum hose not connected and two inlet without hose ( see pics)
Thanks again so much for your help!

 

OK. you have done a lot.

That 1st snap looks like a fuel hose, maybe the return hose, as the next snap shows the fuel cooler without hoses, so I will assume that unit has been by-passed, common enough thing. There should be a fuel hose from that B Bank FPR Outlet running to a fuel pipe spigot poking out of the bulkhead, just below the brake booster on a LHD car. I reckon its there, or you would have fuel on the ground.

That resistor pack plug and socket can stop the Injectors from firing, BUT, you have the clicks on throttle opening, so I would deem that OK for now. Cleaning it will do NO harm of course.

My next suggestion is to get some Starting Fluid, Ether, whatever, and spray into each aircleaner snorkel, as someone cranks that engine. If it "farts" then you have stuck Injectors, BUT, all 12, very unlikely.

Just because I did this. I WARN all that will listen:
NEVER attempt to start a V12 with the air filter covers and elements removed. A known problem V12 CAN and WILL belch flames out of the throttle bodies. NOT good for the paint nearby, or your underwear.

Something else to check, just as a "make sure" item. Prime the fuel system, turn OFF the IGN, loosen the clamp on that return hose, either at the FPR, or the spigot under the booster. It should have fuel in it under NO pressure. If its dry, let us know, there are other things at play.

This is the Aussie Starter Fluid, no, its not pretend, that is what it is called, and it works well.

 

Forgot the attachments I promised.

The EFI schematics are A) Australian etc cars, 2) USA cars. Not sure what spec you guys got. Not much difference in the big scheme of things.

Many more write ups on all sorts if you want them

 

And don't forget lost eyebrows!
NOT only V-12 will do that, also the Lowly Mercan V8!
(Wasn't me, but Oldest Brother had some explaining to do when he came in Singed!)
We don't mess with such weak sister stuff on the farm.

It WILL start, even at 7:1!

 

Hi Grant, tonight I will prime the systyem and check the reurn fuel line to ensure gas is in fact going to the fuel rail.
If eveyrthing is good I will apply a bit of start fluid in the air intake when cranking the engine.
I will also check the current on qn injector to ensure they are working.

I was wondering if the ignition could bde at fault here, I remember i had a car and the current was going to the spark plug when the ignition was ON but on the starting position, no current was going to them. I replace the switch nd the car started. Could it be similar here?
I ll keep you in the loop.

 

in the mean time last week end I did a lot of work in the interior of the car:
changed the dash
replace the swunvisor clips
fix the rear door mechanism on the RL
Repaired the center console holder the gear shift and ashtray. Ther guys painted it brown it look soo bad.
replace the wiper fuse




clean the interior
replace burnt lights
etc.

 

The red really looks great.

Jeff H.

 

Very nice wood on that dash! Well done!
(';')

 

Hi Grant,
tried with Engine starter tonigh. No luck, couple of back fire only.
I checked the spark plugs, still dry as the Sahara.
Question: When I trun the ignition ON and check the power on the injector lead, both prongs have power. Is this normal? Should only one wire has power? I thought there was a negative and a positive on these? Please explain.
The manual said that the timing is 18 degree BTDC at 3000 RPM. However, what is the timing when the engine is not running? 10 BTDC?
Assuming it is 10BTDC, Does it mean that the rotor is point right at the lead of piston 1A on the distributor cap?
Still hanging in there, thanks for your patience.
Please confirm,
thanks,
JP

 

JP.

Unplug any Injector, Volt test the plug, that should give you volts on one. With the loom plugged in, 12v on both is "normal", and the ECU, and its associated bits, switches the Earth to activate them.

AND

Volt meter on the WHITE wire of the coil, IGN to ON =12v approx, go to start position, volts should NOT drop anymore than 1-2ish. The electrical section of the switch may well be dropping the volts at Start, very common now.

PDF attached.

Timing:

I set all mine at 10BTDC, static. So close in the real world.

At that static, the rotor should be pointing at the #1 cap post, dead centre??, NEVER looked. BUT the pointy tip of the metal star wheel would be dead centre of the pick up probe at that position.

Another PDF attached.

ALSO:

When the engine is cranking, place your hand on ANY Injector. Do you "feel" it clicking?. I say "feel" as there is a lot of noise going on in start position, and you would be flat out "Hearing" that click.
My reasons are simple. That shielded wire you tested may still be at play, coz, as I said, if that shielded wire does not instruct the ECU there is activity, the Injectors stay dead. Same with the CTS that you have bridged.

MORE, coffee has kicked in.

Ign ON, fuel rail primed, open the throttle 3 times, you hear the clicks, as mentioned before, return to idle position, go for start, and see if it farts, or runs a few seconds. Every time you open the throttle with Ign ON, the Injectors squirt fuel into the beast, and then spark makes it go Bang. If that gives no joy, then there is either:
Spark loss, Ignition switch issue
Injectors jammed, all 12, NAH.
VERY old spark plugs, that cannot handle the Compression pressure restrictions. NGK BPR6EF is what I use.

You mention some backfiring?, does this sound like its in the exhaust, or the Inlet? If its Inlet, then the timing is possibly out of whack.

We will win, worry not.

 

Hi Grant,
Stupid me!! I mixed up Bank A and Bank B in my distributor leads. I fix them all up. No more inlet fart and it seems that the motor wants to start as it giggles when I crank it, expacially when I depress the gas pedal. I also have a smell of gas/fume after I crank the engine

• I Volt meter the WHITE wire of the coil, IGN to ON and I got 12.65 volts
• I checked the timing as per instruction and the rotor points to the #1A cap post at 10BTDC, and the pointy tip of the metal star wheel is aligned with pick up probe at that position.
• I still have to check the Injectors when the engine is cranking. I do hear it clearly when it the ignitionis ON and I rotate the throttle rotary disc.

I l keep working on it again tonight after work. Coming along a bit at the time..