I ran out of beer, its an Aussie thing sometimes, and I dont really count them, and just finished after ALL DAY changing the serpentine belt on the X Type. STUPID layout for a service item.

I would rather do V12 HE spark plugs, than do that belt again.

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

They fire twice per 4 stroke cycle based on the pulse from the trigger board ends.

 

Ok, so last night I unplugged all injector-connectors to check them one-by-one and each one has a clear "click" when turning the throttle a bit... at first I thought I found the problem as not all of them clicked (only 2A,4A,6A,1B,3B,5B) but after turning the engine 1A,3A,5A,2B,4B,6B clicked and the others didn't. So to me it seems the trigger unit also determines which injectors to activate when turning the throttle.
Just to be more sure I kept the connectors unplugged and unplugged the multiconnector to the amplifier, measured everything and got zero ohms from injector connector to amplifier connector and infinite ohm between the connectors of the injectors, so unfortunately all seems to be perfect

 

That is strange to me.

The throttle switch test fires all 12 at each click in all the PreHE and HE that I have owned, and maintained.

By "turning the engine", by how much?, as I am trying to establish why that would do anything in relation to the trigger board,or wake up the other 2 batches, and kill the 1st lot. Something is missing here, and I can think of nothing I have ever had do that.

The trigger board is only activated by the "passing" of the magnet over each end as it rotates. A static magnet does nothing,

The trigger board fires the Injectors (all 12) as the heel passes over each end of that board, 2 triggers for 2 rotations of the crankshaft that completes the cycle, and that is the pulse that the ECU uses to keep the fuel pump running, and signalling the Amp to do the firing, by completing the earth circuit for whatever miliseconds is deemed by the MAP for fuel requirements.

I am now thinking the EFI loom has been compromised during storage.

 

"By "turning the engine", by how much?"
..dunno really, just had the starter on for a second, hoping it would turn the engine enough. First time it did, second time it didn't, third time it did (tried a couple of times to prove to myself that it indeed switched based on position of the rotor.. which now seems should not matter )

"The trigger board fires the Injectors (all 12) as the heel passes over each end of that board"
... really? I thought it fired in two groups based on the seperate two connections/wires from the trigger board to the ECU and the two wires from the ECU to the amplifier, and also the separation within the amplifier (according to the schematic I have).

what I'm fearing... if now only 6 injectors get triggered at a time and the mixture is already to rich, having all 12 triggered will probably make it worse. But since I have nothing left to measure I'm gonna measure the EFI loom tonight. already established that most is ok (measured the values for the map sensor and the temp sensor both at ECU and sensor side), but never measured between amplifier or trigger board and ECU, although I guess the trigger board connection should be ok, was one of the first things I checked, everytime I hovered the heel of the rotor over either parts the fuelpump would start pumping for a bit..

Don't think I have mentioned this before, this concerns a preHE, lucas D-jetronic system.

 

I agree with the batch of 6 as the ends of the trigger board are activated by the passing of the rotor heel.

The TPS opening fires all 12, as the wipers move over the segmants. The orientation of the trigger board/rotor heel has no bearing on this.
This firing of all 12 by the TPS is used to richen the mixture with a "squirt", as the driver opens the throttle during the driving cycle, thus preventing (reducing) a lean burn backfire when accelerating, as the MAP takes too long, by milliseconds, to do this.

I know its a PreHE, just saying the HE, P Digital, is very similar in so many ways.

 

Yesterday I measured the leads from amplifier and trigger board to ECU, no shortcircuits and all 0 Ohm front to back... Tonight I will simply disconnect every connector I can find and measure from connector to ECU, but it bugs me that I just can't make any sense of all of this. Why would my ECU (or the other two, tried them as well) fire only 6? I mean, there must be something telling the ECU (wrongly) it should only trigger 6 instead of 12. In case of short circuit or leakage, I would think 1 group would always or never fire, not alternating... would this affect the mixture during normal or idle operation?

Out of curiosity... under normal operation (not touching the tps) are all 12 fired at a time or only 6?

 

I am as confused as you, and the Amp and Loom is just continually sneeking into the equation.

"Normal" running engine would fire 12, as each end of the board is activated.

TOO hot for the next 3 days, but somewhere in my MANY piles of scribes, in one of my sheds, I seem to remember a Bosch D Jetronic Training Manual, from when I did schooling on this system back in the late 60's ish. If not the manual, hopefully my hand written notes from the classroom.

I found the L Jetronic today, but useless for what we are playing with. It will be there, I am sure, just 40+ years of hoarding is rather daunting at times.

This will give the principle of the system., and trouble shooting etc etc.

Something bizzare has taken up residence during storage.

 

maybe a very late thought, but I was just thinking... since the MAP sensor is vacuum driven, and to my knowledge (which might be completely wrong) the vacuum in the manifold is high with the butterflies closed, and low when full open.. right? so a very low vacuum would cause a rich mixture? so in case I have a leak somewhere (but would not know where, I tested the tubes, maybe a crack in the manifold somewhere) the mixture would also be too rich?
Then again, with the butterflies full open (only way to have it run aside from removing the balance pipe) the engine runs at 1000RPM max, sounding like it has a lack of fuel, while in that case the vacuum would also be close to 0, so it should deliver sufficient fuel...

I just don't know really going mad...

 

"Something bizzare has taken up residence during storage."

 

Your thoughts are true.

This and the P Digital work on

Hi vac = less fuel, such as idle, cruise and over run.
Lo vac, = More fuel, such as accelerate.

This 1000 or so "flat out" is worrying, and that is the sleepless nights.

I have dealt with, and sorted many strange V12's, and the 1/2 engines, and this is really one out of the box.

Air/vac leaks, ok, but on the D Jetronic, give high idle, not able to be reduced by the idle adjustment on the AAV. Most common is the 90deg hoses under each throttle body.

When its running at this 1000, does it sound like its on 12 cylinders?, or sound troubled, as in labouring?

Is there Black smoke out the tailpipes?

 

ok, going to check the 90deg hoses... on the other hand... if these are leaking it would give the engine more air, which it seems to need at idle? just too bizar.

at full throttle, 1000RPM, engine perfectly stable so seems to be on all 12, also judging from the exhausts, both pressure and sound are very stable, my xjs (which runs great, but is '89 so no obvious interchangeable parts) is less stable in that respect.
The enginge does sound troubled but in the sense that to me it doesn't get enough fuel, it seems very lean. This was actually my first presumption that it wasn't getting any fuel and running way too lean. At 1000RPM it has no power what so ever. it won't climb my drive way, which is nearly level. I'm quite sure that on a flat, level surface (where it will crawl), I could stop it by just standing in front of it. Also the engine runs hot very fast, so all points towards being to lean at full throtle, yet rich when iddle...

No black smoke or any other color...

 

I agree on the hoses, but a quick feel will do no harm.

No black smoke, troubled, getting hot quickly.

This will sound silly, but whet teh heck,

The plug leads in the cap, are in the correct posts. I do not mean firing order as such, but the start point, 1A is in the 1A cap post.

These will run with the leads one post out, and not very well, and troubled, AND get hot quick. Also, NO revs.

This drawing is the factory setting, but if someone has been playing with the distributor, highly unikely, it could be one tooth out, but again, not from sitting in storage.

TDC Compression stroke of 1A., should have the rotor pointing "roughly" at 1B spark plug in the head. Some Blue caps cast into the cap at the correct post, teh older Green caps do not.

If you need a walk through to find TDC of 1A, let me know I will do a Doco for you. It is NOT hard, just fiddly. PreHE is way easier than HE, winner.



The Black DOT on the dist cap is the 1A marker.

 

I really hoped this would be it, as I did remove it to check on the triggerboard, so one hop error could have easily been made,but unfortunately, 1A is at the spot you have in your image. And indeed my cap has a "1" embossed at that post. Since storage the only thing that happened to that can is the removal in my quest to find the problem, so no funny business.

Would you know how to test the hall effect switches? most troubleshooting documents I have state to test between 12-21 and 12-22, where at one position of the engine where the connection between the one combination should be 0 ohms, and the other infinate, and after turning that should be inverted. for me both are always infinite, which might make sense since for me these are hall switches, not reed. I read somewhere that the magnet in the heel might loose it's strenght, so maybe it only triggers only one switch, which might confuse the ECU? maybe that would also explain my findings earlier when only part of the injectors get triggered when turning the throttle? ... probably just shooting blanks, but I'm completely lost (as probably already clear )

 

BUGGA.

My testing of either board is basic at best.

The Hall style:

Ign ON, Engine OFF,
Wave my maget over one end of the board, CLICK.
Wave it over the other end, CLICK.

Job done.

I have never done an Ohms etc on any of them.

I have not tested the Injectors that are CLICKING with each end of the board.
If I get a CLICK, it is good to go.
I do not rotate the engine to do this test, it is carried out wherever it last stopped.

The TPS test is the same, and I know from the S2 V12, that all 12 fire with that test, as a very long time ago I was looking for a dead injector, which was 1B. That car now has 640000kms on it, and only stops when the key is turned to OFF. It had a 3 wire, then I converted to 4 wire and a Crane XR700 Ignition system back in 1994.

 

Better men than I have been trying to help so far, but here is my 2cents worth. Go back to basics. Rig up a couple of small squeeze bottles with tiny nozzles that can jet fuel into the intake manifolds. Disconnect fuel pump and see if engine will run and rev using this crude fuel injection method (and respond to the throttle movement). If it does OK, then reconnect fuel pump and do the same. The result will tell you what the engine is not liking , too little or too much fuel.
A couple of years ago my sons Kawasaki 500 twin motorcycle stopped running due to dirty fuel (he ran it dry) I cleaned the carbs three times and could not get the thing to rev over 3000rpm. The problem was that I was always testing without the air filter. I discovered this when I jut held my hands over the intakes to simulate a bit of intake resistance - it revved up straight away. So back to basics to determine the cause.

 

hm... that is worth giving a try.. .but I'm thinking of triggering the coldstart injectors for this... that should also work I guess? ofcourse in this case the fuelpump must be operative, but if my feeling is correct and at full throttle it's running too lean then it should rev-up when I apply power to them.. Anybody knows if the coldstart injectors are 12V? => judging from the diagram it is, so I'll give it a go!

 

OK,

Went looking for that Bosch stuff from my schooling days. 43C in that shed today, gotta LUV Spring Downunder.

Found the generic booklet, "so-so" helpful with the very basic stuff, not the Yellow one I want/need.

Found the Lever Arch file (400+ pages I wrote from the class, and the mice have gotten to it, and then time has faded the scribe to bearly readable. NOT happy.

There is another, Yellow, book somehwere, and I will keep going tomorrow. I ran out of liuid fuel for me.

I am going through the Lever Arch, and restoring what I can, and maybe? it will shed some light. Beer truck is on its way (AKA daughter).

 

" Beer truck is on its way (AKA daughter)."
all hail the daughter!

 

"so all points towards being to lean at full throtle, yet rich when iddle... "
Doing some more thinking... I actually think it's always running way to lean, can you comment on this:
- MAPs makes sure there that the lower the vacuum, the longer the injector stay open
- I disconnect the balance pipe, so no vacuum, so long opening of the injector
- the disconnected balance pipes provide a lot of air, but not as much as full open butter flies (right?)
=> so actually the the low vacuum makes sure it provides max fuel, but with limited air, and at this point the engine runs smooth.

thinking further:
- my injectors fire in two groups of 6, tested this again this weekend just to make sure..
=> since all 12 injectors should fire every time, which it doesn't, the engine only gets half the intended fuel (right?)

Now if only I could figure out why the injector groups alternate rather than firing all at once...

 

These might help.

It is what I have reconstructed so far from that huge paper file, and memory.

The Throttle Switch needs to be checked.

The fact you have pulse on that switch when returning to idle from the count test is wrong, and indicates the "direction" thingy inside that switch is not doing what it should.

The Idle setting is a slightly richer setting, just for idle. The wipers etc inside that switch may respond favourably to a simple clean?