I found a free processing program that is similar to MS Word. Libre. there is one other that I used in the past. But, it's name escapes me.


I opened Grants doc. in Libre with no problem. it offered the convert to PDF feature as well. I did that.


My daughter is stuck with MAC. She gets doc. documents and sends them to me. I convert them to PDF and send those, she can handle them.


W/O entering a MAC vs PC wrangle, she thinks only MAC is for the artistic. She definitley is talented in art. .


Me? A straight line is a major accomplishment on paper wood or any place else..


Carl..

 

Aubrey,

I found this link on the Series 2 V12. May be helpful.

JAGUAR V12 FUEL INJECTION 1975-1980 - D Jetronic / AJ6 Engineering

 

Ah, yes, Bob... I just found that too !
Between that, and what has been provided here... if I am able to grasp and retain all of it...
I will know EVERYTHING ! !
HEEE HEE !

 

I chuckle with you.

Side note. Check the rubber bushings on the throttle linkage where they make the 90 degree turn to the throttle body. Mine were disintegrated.

 

I think you've helped me find something big, ics.

I fiddled with the air temp sensor ohms in a recent thread. Seems ok.

Checked resistance of coolant temp sensor, cold engine, when just over 20C. 2,300 ohms. About right

The range....

At freezing - 5.9k
25C - 2k
60C - 600
80C - 300

So I warm the car up today. Figured I'd check it at another temperature. Around 75C with a laser thermometer. 1,990 ohms.

Argh.

The ECU thinks the engine coolant temp is 24C or 75F when it is really pushing 170F. More fuel than is required.

So I jump the CTS terminal with a wire. Ohms then zero in theory. Meaning (assuming) ECU thinks really really hot and then leaner fuel. Drops a few hundred in RPM, a little ragged, but smells lean, not rich.

Posting here as OP has nearly the same car and should go thru this exercise.

Mail order sensor is $25-ish. Local is $45-ish,

Thank you.

 

You guys are amazing !... I'm learning more here, with every post, than I've learned about cars in the last year !

 

Just an update...
When I've had time, I've tended to a few recommended checks.
Every time I start the engine, there's a new symptom. Fortunately, in most cases, one of the old symptoms disappears.
I HAVE managed to get the engine running on all 12... on occasion. Had it out on the highway, and was able to sustain 120 - 160 KMH.
Unfortunately, a VERY nasty new symptom showed up after that... making the car now, almost un-driveable.
OVER-FUELING at all times... even under full throttle, until it revs up some.... where it then dies off.
Setting fuel pressure regulators, exposed a concern, where the left bank won't hold more than maybe 15 PSI.
Bleeds off instantly after the switch is turned off.
Yeah... internal leak somewhere.
Has now fouled 4 spark plugs, but good.


At the moment...
The distributor rotor... specifically, the magnet.
This one will pick up and hold a 3/8" lock washer... but not much more.
Is that adequate ?


Gawd, I'm having fun

 

The magnet sounds okay to me, if she's firing then I wouldn't worry much.

The over-fuelling, I run a later system to you, and I'm afraid it's all I know, but I'll share what I do know... Firstly, the temp sensors, Have you checked their ohms readings when the engine as cool and when it is warm? It may also be an idea to check the readings back at the ECU (I'm afraid I don't know the pin numbers for yours) to see that there isn't any resistance or bad contacts within the circuit, as with the way things work, the higher the resistance the more the fuel, so we don't want any extra resistance.

Do you get smoke out the back? If so what colour? I've seen mine run without the CTS connected, LOTS of smoke, and without the ATS connected she could drink twice the fuel... And foul a few plugs while she was at it.

Speaking of fuel, I assume you've had the rail cleaned and possibly fitted a new filter? It may be a silly question, but are you sure you've lost 4 spark plugs and not 4 injectors? It doesn't take much to block 6 injectors, trust me I've been there...

 

Agree with Nathan on the magnet, that is sweet enough.

The FPR's are a needle and seat arrangement, and they get pitted over time. Non repairable. Most D Jetronic systems I have had, dont hold the rail pressure too long, never really caused much grief on mine. As long as the adjustments will allow the proper pressure to be set whilst the engine is actaully running works for mine.

They also stick, and with care, a thin blunt shaft shoved up the outlet snout and pushed, CAN, sometimes, free them up. OFF the car is the only way to do this.

I really would source a pair of new units.

Stuck injectors will give that bleed off, as will the "cold start" injectors.

I remove the 2 cold start injectors on all V12's and plug the rails etc as needed. They really are a PITA item.

The injector wiring loom in the bottom of the "V" is always a suspect, and it will/can internally short and hold banks of injectors open, and then overfuelling is in your face.

 

Yes, Nathan... flushed out pretty good.
4 spark plugs wet, to soaking wet.


Grant, when it's about - 24 degrees C, kinda need cold start injectors !
However, in an effort to diagnose this, I will do as you recommend... as well as the regulator trick.


In order to help eliminate a variable... regarding all the temp sensors ( excluding the one for the guage )... is there a method to connect / by-pass ? then in susch a way, that would make the computer think that the engine is hot ?

 

OK, my findings over the years.

The cold starts were fitted, deleted, refitted, etc by Jaguar throughout the V12 production. These 2 injectors fail mechanically, and/or electrically, and dribble fuel constantly. That is why I remove them totally from the system.

They only give a short spray of fuel at certain temps, and that is all. Once the beast is runnong the "ON" time for the injectors is extended to allow more fuel to flow to keep a cold engine running, simple enough.

This temp comes from the coolant temp sensor (CTS) on the LH stat backing.

Also the MAP sensor on the rad support panel supplies a prime fueling signal as well, mainly based on vacuam. They fail internally, and overfueling is rampant.

Bridging the terminals in the CTS plug will trick the ECU to HOT. The PreHE may be a fair mongrel to start like that.

My "cold start" procedure on ALL V12's is simple. ON the Ignition, press the throttle pedal to the floor and release, start the engine. This simple pressing actually "fires" the 12 injectors, and sprays fuel into the cylinders, just like the cold starts, but WAY more reliably. Also works for HOT shutdown restarts.

 

Will do as advised, Grant.
Thanks again, guys...


and


HAPPY NEW YEAR !

 

Gadget thinking!!!


Keep the cold start injectors, but, wire in a switch to energize them for a short spurt to enable a cold start. Very similar to the prime bulb on my 2 cycle engines. Unfortunately, that doesn't cure the leak issue. So, a solenoid switch to cut off fuel unless energized along with the manual prime?


But, all in all, Grant's technique of elimination and forcing a preliminary squirt of all 12 injectors seems the best.


Really old engines had primer cups for each cylinder!!!

Carl

 

Geez, Carl... add even MORE wires to this nightmare ? !


OK... I finally decided to quit fooling around. Do this step by step.
Removed both fuel pressure regulators. Bench tested them. The one from the left bank, works perfectly... set it to 31 PSI.
The one from the right bank... not so much. Stuck in a wide open position... nothing I could do to make it deliver more than about 6 PSI.
Looks like right now, I need a regulator. Not very happy with this car, so I prefer to not buy expensive new parts... just good old stuff will do here.


We have a Jag specialist place, about 250 miles from me. I'll contact them.

 

Its a Bosch regulator.

Used on all sorts of cars running the D Jetronic system. Merc, SAAB, BMW, Citroen, Volvo, etc. Some Fords ran a modified style of taht system, and the FPR is the same.

Look on ?bay, there are usually a few around, and get away from Jaguar specific for the D Jetronic system, as I said, lots of early EFI cars ran it.

 

OK, gentlemen... got a little closer... I think ?


As I mentioned before, this thing had more symptoms than parts.


Here is what is confirmed correct:


Ignition timing
Spark plug gap and function
Adequate plug wires
Adequate cap and rotor
Correctly operating ignition advance systems ( no retard )


Fuel pump... new
Fuel filters ( one before and after pump )
Cleaned fuel tank
Correctly operating return system
Fuel pressure regulators ( just installed one new one ) set to 30 PSI
No leaks, ect
Cold start injectors by-passed / disconnected from fuel system
Idle air control valve functioning properly
"accelerator" system functioning properly.
When engine is shut off, the fuel system retains pressure very well...
.... ( does not seem to bleed off past leaky injectors or the such )


Symptoms:


Upon cold start, the engine runs as new... for about 10 seconds.
Then, starts over fueling... BADLY, and stalls.
Must press accelerator to floor, to get it to barely start... then keep it revving. Decelerating the engine, will over fuel it VERY badly.
Warm up engine, by driving... get on the highway, up to speed ( 110-120 KMH )... really... not too bad. Accelerate from that speed, and this old girl shows it's "bad" side ! DAMN, at high speed, it IS noticeably faster than an HE engine !
Decelerate, and as it gets down near an idle in any gear, it simply stalls...
and is practically impossible to start.
some time later on the side of the highway...
I disable the fuel pump ( took wire off ).
Drove the car at about 40 KMH, for 6 KM, to home, like that
Guess my fist question would be, how does a fuel injected engine run without a fuel pump ? ! ! !


but that aside...
Observed:


At high speed cruise, there is no mis-fire, other than a slight hiccup occasionally... I believe from over fueling.
Under acceleration above 2500 RPM, there is no mis-fire at all. Very nice actually ( it was -22 C today )
If the temp sensor is disconnected, the engine basically will not run.
If the vacuum hose is taken off the MAP sensor / control, the engine will basically not run.
The engine cannot approach anything that resembles an idle... over fueling terribly.
Just to test, I backed off the adjuster bolts on the fuel pressure regulators.... all the way.
That DID help slightly.... but the engine won't accelerate much, and obviously can't reach any speed.
Still over fuels... and mis-fires.
The engine oil IS becoming fuel contaminated.


any ideas ? ! !

 

OK, my take on it as I see it.

No fuel pump no running, as there simply is no reserve of fuel for any EFI system. Maybe 3 - 5 seconds tops.

Out on a limb, so watch out.

Under the LH side of the car is the metal fuel return line. These can/do get crushed, usually bt tyre fitters. This WILL cause overfueling at low revs, due to 80% +/- of the fuel being retuned to the tank. Higher revs, less return, less issues.

The FPR's that you have set, I am assuming have been done ON the engine, with the engine running??, however, I doubt this is the case due to the overfuelling issue??.

Bench setting them is usually way off, due to the supply pressure being no where near the fuel pumps supply pressure and the usage of the injectors, etc.

The fact you wound them all the way out and it ran better, sort of, still has me thinking the return is restricted, and that will cause a back up of pressure. I had a HE in Tasmania doing that, and he found the LH pipe crushed at the front jacking point. Fitted a hose repair section, good as new.

The throttle switch on the PreHE is a strange item, and age is now not its friend. Some respond well to cleaning, and then the time consuming effort of resetting them generally pays off.

The wires of that switch INSIDE the rubber cover do break. The PreHE is driveable in that situation, but depending on which signal wire is AWOL, the quality of the drive is random.

That throttle switch plug DOES fall out of the switch and rest inside the rubber cover, and you will never see it obviously.

I use 2 fuel pressure gauges on the 2 fuel rails, and if the engine is a non-runner, use the prime feature to base set them, it is a balancing act, and must be done proper, then when its a runner, trim adjust them, usually to 29psi, sometimes less.

OR, remove that dual rail nonsense, steal a HE rail, and the LH HE FPR, and convert it. Simply enough, and then you got a vac modulated FPR, and none of this FPR balancing rubbish.

OR, use the HE rail, AND your new PreHE FPR on the LH side (outlet) and manually adjust it to 29psi. This what I use on my HE engines.

 

Yes, isn't that CRAZY ? ! ! ... Should have got that drive on video.


Agreed.. it REALLY IS pointing at a restricted return. Something I neglected to mention above... I've isolated to use the right tank only ( eliminate variables ), and replaced the seized return valve inside the wheel well. Confirmed that it functioned, and watched the fuel flow through it.
On your advice, I'm going to make one more test on that. I am going to disconnect the return hose from each regulator. connect a hose to each, and have it dump into a separate container.
Would be very gratifying if this helps.


oh, about the "bench test" on the regulator...
I simply get in the trunk ( under the boot lid ! ), and connect the hose from the fuel pump outlet, through the regulator. too easy


I'll do the "test", and get back.

 

Test results:


Set fuel pressure regulators ( installed on car ) to about 27 PSI.
The return hoses / tubes from each, to the fuel tank, are disconnected... and instead, a hose / rube is connected to the exit of each regulator... and allowed to drain into containers outside of the car's system.


Start it up


No difference.


Should mention.. I have opened up that throttle switch. It's flawless. Injectors cycle as they should. Wires / connections fine.


Is it possible for the vacuum operated "MAP" sensor, to be providing such a ridiculous signal... making the mixture so rich, as if the engine was at full throttle ? ... and would this rich condition be so bad, that the engine would have to be held over 3000 RPM, just to keep it sort of running ? ( the exhaust smoke is indescribable )

 

That MAP can reek havoc.

It is basically a brass double bellows, much like a weather Barometer, and teh bellows crack with age.

Main issues I have had with them is the resultant vac leak, and the stumble off idle as you accelerate.

Some have an Allen key adjuster under the end plastic cap. The threads of that are very coarse, so tiny movements makes a big difference. The adjuster is exactly the same as the fuel mixture screw on the carbies of earlier cars. If you move it, say 1/4 turn, and nothing changes with the engine, best guess is its toast.

Vac test it, using your mouth, if it holds vac, it would be deemed OK. That is the test I used when looking for one at the wreckers many years ago for ours, and found one on a Citroen, and it look NEW, so I nicked it.

Next would be the injectors out and tested by the specialsists. They may be "dribbling".

Also try the bridging of the Coolant Temp Sensor plug with a paper clip, and see if the smoke reduces. Whilst you are at that point, make sure the ATS and the CTS plugs are plugged onto the correct sensor. They look the same, and the wires are the same length, and even I have mixed them up in the early days.