XJS ( X27 ) 1975 - 1996 3.6 4.0 5.3 6.0

Making a new Injector Harness for the H.E

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Old Dec 10, 2016 | 08:12 PM
  #141  
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Originally Posted by Grant Francis
That large split conduit on top of the LH inlet manifold is where that coax is located, again from memory.

It travels around the back of the engine, probably more closer to the heater tap than the oil sender, but still in that general area.

Not sure if I sent you this Pin Out earlier, so here it is again if so.

Attachment 140052
Grant just read your print out.

That last paragraph is interesting. That RH intake manifold earth....that is where I cut off that redundant cable. There is about 3 other earths there. 2 are a larger gauge...one smaller. The smaller one looks debatable....mmmmm.

Need to get home!
 
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Old Dec 11, 2016 | 02:57 AM
  #142  
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Ok....just got home.

Back to the garage. Got the lad to crank the engine whilst I earthed out an old spark plug. YES. I had a spark. Not sure if it was fat and blue. It was kinda medium sized and white...I dunno the rotor is spinning and we have spark so that is good right? Hard to gauge it as I am not sure what a good spark looks like coming out of a spark plug (first timer me)

Well now to get onto the stuff mentioned today. Ie. This coax cable for the tacho, those earths on the RH intake manifold and any other suspect stuff near the firewall/oil sender area.

To be continued....
 
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Old Dec 11, 2016 | 03:44 AM
  #143  
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Goodo on that spark, that is more than enough to fire that engine.

That coax has NOTHING to do with the tacho, it is used to supply a "tacho style" signal to pin #18 of the ECU.

I want you to check something simple and easy. Look at the CTS (Coolant Temp Sensor), that is in the back section of the LH thermostat housing. It has a plug on it the same as the injectors, It has 2 wires, and they can become erratic, broken, etc, so the signal to the ECU is lost or fuzzy. Example: A running V12, grest, unplug the CTS = DEAD V12, its that simple and critical.
 
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Old Dec 11, 2016 | 03:50 AM
  #144  
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Ok I will check that right now... just came back from the garage.

I don't think my beast has this "coax" cable at all. If you look a the pics coming from the Amp they are all regular single core wires:



And no Coax cable in the harness laying over the LH intake manifold:


I looked in that firewall area too...nothing.
Weird...
 
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Old Dec 11, 2016 | 03:57 AM
  #145  
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Nevermind...i found the coax.....the green wire coming from the amp is spliced into a coax....checking it now.....

Checked the CTS with the Bosch style plug on the LH side. Looks good. Traced out the crimps. Good also.
 
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Old Dec 11, 2016 | 04:03 AM
  #146  
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Found broken coax wire! This is getting exciting.....

stay tuned
 
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Old Dec 11, 2016 | 04:10 AM
  #147  
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Hi Bro

Nearly There

You and the Wizard have 'Cracked it'.........!
 
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Old Dec 11, 2016 | 04:48 AM
  #148  
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Nah false alarm..

I must of broken that coax when I pulled off the tape to inspect it.:



Nevermind. The P.O used a lug but I have decided to solder it directly. Green wire to coax centre conductor:





I finished it off by wrapping some self amalgamating tape around it and put it back in the flexible conduit.

There is one other splice of that coax near the firewall but it passes the tug test and it has been heatshrunk. Seems ok.

Also checked my Coolant Temp Sensor. Plug end and wires. She seems apples:






mmm.....
 
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Old Dec 11, 2016 | 04:58 AM
  #149  
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What is the mmm Wire Bro?
 
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Old Dec 11, 2016 | 05:11 AM
  #150  
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that is just me thinking.....


Guys real silly question:

I am sitting in the car looking out the window. My right hand side is "A" bank correct?

"A" bank is closest to where the EFI harness plugs into the connector going back to the ECU correct?

Just making sure I haven't mixed up A and B banks.....cause that would be very silly of me!
 

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Old Dec 11, 2016 | 05:35 AM
  #151  
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Originally Posted by paulyling
that is just me thinking.....


Guys real silly question:

I am sitting in the car looking out the window. My right hand side is "A" bank correct?

"A" bank is closest to where the EFI harness plugs into the connector going back to the ECU correct?

Just making sure I haven't mixed up A and B banks.....cause that would be very silly of me!
Yes Bro

That is correct, as you look out the Window 'A' Bank is on the Right Hand Side
 
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Old Dec 11, 2016 | 05:59 AM
  #152  
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Hi Bro

If you've got some time on your hands and or are out of ideas, it might be worth checking the FPR (Fuel Pressure Regulator) on 'B' Bank.

Make sure the King Wire is off the Dizzy as before and all the Spark plugs are in the engine.

If that No1 Injector is still in the Pickle Jar that is OK no need to put that back for the moment.

Then undo the Pipe that goes into the FPR on 'B' Bank and put some rag around it loosely, so you can see whats going on, then Turn the Key.

Petrol should come shooting out of there like a Fire Hose, in a sort of WTF was that! kind of way, hence the need for rag to contain it.

But if it just dribbles out, then me thinks that's your problem.

As long as there is nothing to spark and no Barbies anywhere near, your Car reassuringly shouldn't burn to the ground on this occasion.

But if everything is working OK that Stream of Petrol coming out should be powerful enough to shoot right over the other side of the Car.

Again hence the need for some rag to contain it and don't let it go in the Vee.

A blanket and Fire Extinguisher Optional if that will make you feel better?
 
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Old Dec 11, 2016 | 06:03 AM
  #153  
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Whew! Well I am glad I don't have that X in that category then..

Just thought I'd check though. I have looked at that thing so bloody much I am going googly eye'd

Like Grant said it is probably something silly. I'll be surprised if it is anything I haven't touched though.

At least we have narrowed it down to the symptom: The injectors will not squirt upon crank.

And...I know the ignition is working as I have spark.
 
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Old Dec 11, 2016 | 06:18 AM
  #154  
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OK, nearly time for beauty sleep.

Out on a limb a tad here.

Refit that injector.

Refit that coil HT lead.

Tuen ON the ignition, and press the accelerator twice, and then continue to turn the key to "start". The engine should fire on the fuel you just squirted into it with the accelerator.

If it runs and dies, you have lost the injector pulse signal to pin #18 of the ECU, OR, the CTS is not supplying a signal.

If it continues to run, drink whatever is handy.

Ya got one hour before I shut down, and come back tomorrow.
 
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Old Dec 11, 2016 | 06:19 AM
  #155  
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Hi Bro

You need proper fuel pressure to make those Injectors Squirt, that was one of the problems I had with my Car.

As soon as I swapped the FPR for the one on my Parts Car, I certainly noticed the difference straight away.

But then I found my Injectors were blocked but that was understandable after standing for such a long time.
 
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Old Dec 11, 2016 | 06:33 AM
  #156  
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No go....Starts then dies. Crap

Sorry got to sleep now too.....fresh slate tomorrow...

Thanks for everybody's help today.
 
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Old Dec 11, 2016 | 08:03 AM
  #157  
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Bro

Just a thought in case you can't get to sleep (Lol)

Are you still using the Old ECU or the New one?

You ordered that New ECU for a reason (I believe you said the Car was cutting out?) Do you see where we're going with this.

Well unless you bought it for a 'Bookend' then there may not be a better time to try it out than now, because it seems the Old one has got some sort of problem that may even have got worse by now.

Who knows the New one may have 'The Goose' running straight out of the Box, with the added advantage that you won't have to go through this Agony anytime soon all over again if it works.

Just wondering what the 'Woz' may think about that.
 
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Old Dec 11, 2016 | 09:48 AM
  #158  
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Question for Grant: OK, so are we at the point where we are sure that, for whatever reason, the ECU is not getting the signal to fire the injectors when the car is being cranked?
If so, could this be that the starter relay has gone home and is not telling the ECU to fire the injectors while cranking?


Points for Paul :
1) Have you cleaned up that earth wire where it was earthed via that self tapper through the plastic cable clip and ensured the earth is directly against the bare metal of the body?
2) There are two wires that emerge from the bottom of the dizzy and go to one side of a rubber plug connector in the bottom of the V. The other side of the rubber plug takes the two wires to the plug in the SIDE of the ignition amp and these wires tell the amp that the dizzy is turning and when to switch the coil. Test for continuity. Carefully prise the two sides of the rubber plug apart (not that easy) and clean and check the wires are not broken.
3) Inside the coil the rotor arm can only fit one way. BUT carefully check that the star wheel (the 12 pointed graphite looking thing) is intact, dry of oil, clean, and has an even and close gap to the pickup thingy it turns past. This is the bit that makes the coil switching signal to the amp (using HALL effect) that goes through the two wires that emerge from the bottom.
If a blank is drawn after Grant's further suggestions:
3) Can you get hold of a spare ignition amp?
4) Can you test the shielded wire for continuity from the amp connector to the ECU plug pin?
Greg
 

Last edited by Greg in France; Dec 11, 2016 at 10:08 AM.
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Old Dec 11, 2016 | 01:13 PM
  #159  
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I would suspect the start relay is good, it puts 12v on pin 26 when the key is turned this I suspect would tell the ECU to provide the priming pulse.

Jaguar may do it differently but all the ECU's I've worked on need a tach signal to tell the ECU that the engine is cranking, other wise how does the ECU know to fire the injectors once every engine cycle, the only tach pulse is from the shielded wire.
 
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Old Dec 11, 2016 | 03:25 PM
  #160  
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Guys thanks so much for the help overnight. I am awake now...just.

O.B I have been thinking the same thing for the last few days about the 16C. Could it be that through all this my 6Cu has finally died? My only concern if it is a wiring error on my part I didn't want to risk cooking the new 16CU...then I would be left with none....so that is why I kinda wanted to find out definitively what it was first. Still.....

Greg. Thank you so much. As per below:

1) Have you cleaned up that earth wire where it was earthed via that self tapper through the plastic cable clip and ensured the earth is directly against the bare metal of the body? Yes. I moved it to a known earth closer to my radiator. It had other earths going to it and makes contact with the chassis better. I am still convinced this is a redundant wire however it is there just in case.
2) There are two wires that emerge from the bottom of the dizzy and go to one side of a rubber plug connector in the bottom of the V. The other side of the rubber plug takes the two wires to the plug in the SIDE of the ignition amp and these wires tell the amp that the dizzy is turning and when to switch the coil. Test for continuity. Carefully prise the two sides of the rubber plug apart (not that easy) and clean and check the wires are not broken. Will check shortly...
3) Inside the coil the rotor arm can only fit one way. BUT carefully check that the star wheel (the 12 pointed graphite looking thing) is intact, dry of oil, clean, and has an even and close gap to the pickup thingy it turns past. This is the bit that makes the coil switching signal to the amp (using HALL effect) that goes through the two wires that emerge from the bottom
Will check today...

Greg, if this hall effect coil was damaged or misplaced, or even the wires damaged, this wouldn't effect my sparking would it? It is just that yesterday I was getting a spark ok via the plugs. In other words if this was in any way affected could I still possibly get spark at the plugs?

Just have the dizzy cap off in this picture before I took the rotor off a few months ago for reference:

Thank you for confirming that Warrjon. This start relay is on the RH side of the engine bay correct? Heading back towards the firewall where the ECU harness disappears? (Just for future reference)
The pressure is on now. Kids home for school holidays. I have things on during the week and I leave Sunday morning for

Crap I don't want to go to work for a month without this sorted. Hope I can get it this week.
 

Last edited by paulyling; Dec 11, 2016 at 03:34 PM.
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