The good news is that the XJS has one of the easiest to change fuel pumps I've ever seen.

 

I am back working on the car. I received my new TPS, Fuel Pump and Filter.
For now, I am going to disable the fuel pump circuit by removing the fuel pump relay until I resolve the Injector pulse issue.
*Installed the new TPS and I have it set at 0.34v (Closed Throttle) finally. Still no injector clicking when turning the throttle to WOT. Does the WOT switch have any role to play in this exercise?
I have removed all of the home made injector harness from the injectors and checked each trio of injectors.
I tested each injector trio individually
At the resistor pack plug, I have the following:
When I briefly tap a ground source to >>
O/U wire, I get Injectors A- 2,4 and 6 to click.
O/W wire I get Injectors A - 1,3 and 5 to click.
O/S wire I get Injectors B - 1,3 and 5 to click.
O/G wire I get Injectors B - 2, 4 and 6 to click.
Tomorrow, I am going to revisit the DWW from the Amp back to Pin 18.
I have a piece of speaker wire tapped into Pin 18. Using my newly acquired not familiar with Oscilloscope I am seeing a voltage spike at Pin 18.
I am still learning how to set up the Oscilloscope properly to get a reading I can save. Presently, I just have it set on automatic and when I crank the engine I see a voltage spike on the Oscilloscope screen. I have to learn how to set the trigger, duration and peak voltage. The instruction manual is not very user friendly.


speaker wire attached through a drilled hole to ECU connector

I will also revisit the TPS/CTS/ATS wiring. On my car there is no solder blob near 5B.
The wires to the CTS and ATS come off the TPS plug

one of the Y/B and Y/K wires at the TPS connector go to the CTS and ATS respectively.
The CTS U/O and the ATS R/U wires go directly into the main harness to the ECU

 

Seems to me that the throttle must be opened rather quickly to get the click from the injectors; that's how I recall mine operating

I don't think so, no. I think it's purely a TPS function. The TPS detects not only how far the throttle is open but, more significantly, how quickly it is opened. The idea is to increase pulse width when the throttle is opened so as to prevent any hesitation. This function is akin to the accelerator pump seen on many old carburetors.

The injector click with key on, engine off is, I think, an anomaly of the circuit...albeit a useful one. I don't think it occurs with the engine running....as the injectors are already opening and closing like crazy.

Cheers
DD

 

Thank you Doug.
The thing is when I turn it to WOT the most obvious click I hear is coming from the WOT switch. As per all of the posts I have read, they all say I should hear the injectors click all at once when the throttle is quickly turned to WOT. That is not happening here. Based on what you are saying, Can I remove the WOT switch from it's location so that it will not click when I turn the throttle to WOT? Or not.
My injectors are in good shape as I had them serviced by SD Faircloth (Jaguar Injector Service).
Based on all of the tests I have performed, I will surmise that the electrical harness is good. What is missing is the ECU sending the ground to the injectors.
I have in my possession 3 ECUs. The original 6cu and 2 16cu on loan from members of the forum. What I do not know is whether the loaner ECUs are any good.
The members who loaned me their ECUs could not verify whether they were working or not, so I do not know what I am working with.
I will get on with it today and report back.

 

You will have TWO WoT devices: the microswigch on the capstan, and the vacuum switch on the rear of the QA bank. either or both can be removed for your testing purposes with no danger. This is the vacuum switch:



Just a thought: have you cleaned up the earths (grounds) on the frame under the carpet just alongside the battery?

 

Greg: Thanks for that info. Yes, I have cleaned and cleaned again every single ground point I could find on the car and added an additional ground from the engine to the chassis.
All 7 (including the DWW braid) of the ground circuits at the side of the battery(G6) and at the ECU connector check out OK.
I installed a new CTS and I am going to revisit the CTS/ATS circuits back to the ECU connector today.

 

Sanchez
I have the factory workshop manual, hard copy. It covers both the pre HE and the HE engines. I have just read the PRE HE section and it has a great many very detailed tests for no start. One of which (pre HE remember) is that a failed thermotime switch will cause no start. Now I have NO idea if the HE has a similar system; but it DOES have some sort of thermotime switch which on US spec cars activates on cold startup for about 50 seconds (on the Rest of the World cars for 15 minutes). Now, maybe, just maybe, if this fails on an HE the same no-start could occur? Repeat, I have no idea if true or not, but worth a quick test.
On the HE engine, on the A bank water rail REAR water manifold, underneath the inlet manifold, hard to see but there, you should find a temperature switch:

This can be disabled by just removing the two connectors. Then trying to start. I am not, repeat NOT hopeful, but why not try it.

More importantly the Manual has several pages of detailed tests on the PRE HE system, including the no-start condition and absolutely loads of tests. If you would like it, I will make pdf copies of these PRE HE tests, as they will, in any event, give you a good diagnostic path to follow, even if some of the actual test are not relevant.
One test mentioned, is to test for the incoming signal to the power resistor (the thing on the rear of the front right headlight nacelle). It is possible that the ECU is switching, but that the signal is not getting down the loom, for example.
Greg

 

Thank you Greg. I would appreciate the PDF files you offered. One can never have too much information.
Based on my interpretation of the schematic I have, the ECU sends power to the resistor pack through the KS (pin11),KG (pin 29),KU (pin12) and KW (pin 30) wires. this power then goes through the resistor pack and exits on the OS,OG,OU and OW wires.
However, there is also a set of OS,OG,OU and OW wires coming from the ECU that sends power to the injector circuit after the resistor pack. See schematic attached
Which wires are the ECU signal wires you mentioned in your post?

 

In this case, where in the electrical system might one TEST to see where the signal from the ECU, TPS or the resistor pack is failing to make it to the injectors - or to eachother? I would imagine that when the throttle is quickly turned to WoT and its signal is sensed by the ECU (if it ever reaches the ECU) the ECU then sends its out going "FI click" signal to the ???? resistor pack,,, which then signals the injectors?

I'm trying to follow along here.

To me, the fact that the very predictable "click" is not clicking is important evidence that there is something going on between the ECU and the cigarette box resistor pack or from the TPS and the ECU...and it's connection points.

Will/should there be a click independent of the DWW?

I apologize if my suggestions are off the mark but it's what came to mind.

As Doug said it's purely a signal from the TPS that triggers the ECU to click all them injectors at once - its not all them other switches and gizmos. It a direct line of communication from the TPS to the ECU. Either the ECU isn't getting the signal, not reacting to the signal OR all that is working rightly and the corresponding signal from the ECU (from which pin(s) on the ECU???) isn't making it up to the resistor pack. Or, it is making to the resistor pack and the resistor pack isn't delivering it to the injectors?

I'm that dude standing in the side who's just learning,,, and,,,, lol,,,, maybe interrupting.

 

A very good point Jay. And very well taken. Nothing is off the mark. It is cloudy and rainy down here so it a good time to research and ponder. Right now I am just researching stuff. The workshop manuals are not very clear and I am depending on those who have done this stuff to bring some clarity to the situation.
Me, not knowing exactly how things are theoretically supposed to work, leaves me grasping for straws.
I have checked every single circuit from the engine bay to the ECU harness and they all check out OK.
What I am unable to do is verify what is happening at the ECU when the engine is cranking because I do not have an assistant to do the cranking while I perform tests to see whether the ECU is responding to the inputs it is receiving.

 

I think we were writing a post at the same time this morning...

From your diagram,,, unless BOTH pathways are failing, the one(s) from the ECU that goes thru the resistor pack AND the ones that by pass it (I'm guessing the bypass might be the WoT "click" circuit) the thing that's left is the injector harness? It seems highly unlikely (unless something has went south in the ECU) that both pathways are failing...

Mine is a 1990. Don't know the differences. But my car has a harness/loom that terminates as a single plug that is plugged into the top/bottom of the resistor and another that comes out that goes directly to the FI harness. I'll be very interested to know where and how them other 4 wires are integrated into the FI harness/loom...

I think you are about to solve this...

 

Sanchez
Attached the PRE HE injection testing routines. However I have some points and questions:
You must find a helper so you can listen to and test things while cranking etc.
The HE system is NOT the same as the Pre HE; but, the HE was a later more reliable more digital development FROM the pre HE, and they are both Bosch systems (even though made by Lucas under license). Therefore I will be surprised if the test routines are not very similar, even if the values of Ohms etc are a bit different. Reading the attached it sounded very familiar,as you will see. i have a feeling that the power resistor on the pre HE was incorporated with the amplifier somehow, there hardware there is different. But the description of its workings seem basically the same. I think that the test routines if followed wil establish what the fault is, even on the HE system.

One important point: on the HE, at least, a wire goes from the starter relay (RHS rear of engine bay under a plastic cover) to PIN26 of the ECU. This tells the ECU that the starter is operating so fire the injectors. Check that this wire IS carrying 12v to pin 26 when the engine is cranking.

The questions:

1. as you are sure you have spark, does the engine fire on ether squirted into the throttle bodies?
2. is the fuel system back together and fuel in the tank (assuming the new pump has been fitted)?
3. have you undone one of the front two injectors, leaving it connected to the rail, and looked to see what happens when (a) you crank and (b) you make the injectors click by earthing whatever it is that makes then click?

I think all this is important to check before doing anything else. Because if you can somehow make the injectors click, fuel SHOULD come out of the injectors, and if it does not why not!!
Keep at it, we will all know loads more about the injection system by the time you are successful.

 

The system will not load my PDF, will try later

 

@Jay: New home made harness. It has been tested and tested to see if I screwed up somewhere. but no, the injector harness is as good as gold.
My car also has 2 plugs. (1) 8 wire plug going to the Resistor pack and (2) 8 wire plug going to the Injector harness. They both come from the ECU
@Greg:
Yes. I have 12v from the starter relay to Pin 26.
Yes the engine fires up when I squirt ether into the intake. Using the Oscilloscope I see a pulse at Pin 18
No. I have not installed the new fuel pump as yet.
Prior to the fuel pump failing, I had performed the injector test which you had recommended in an earlier post. No injector activity while cranking: fuel sprays through the injector when I create a ground path for the injector. I tested both injectors 1A and 1B. I thought I posted these results but looking through my posts, I apparently did not. Sorry.
I will try to get one of my sons to come over for a few hours. they live 3-4 hours drive away on a good day.
Looking forward to seeing the PDF.

 

Sanchez
They are uploaded on post 213

 

Thanks Greg. Appreciate it.

 

Hello all:
1) I decided to revisit the TPS circuit today and found some green crud way inside the TPS plug coming from the main loom. I had cleaned this before but apparently I did not do a good job (I am now questioning my ability to clean stuff lol). This time I used a drill bit with some wet/dry and was able to clean it properly this time. When I was doing my tests I had only partially connected the TPS pigtail to the harness so I was getting a reading. Pushing the plug all the way together I was losing the signal. Now it's all good.
Result: When I goose the throttle I hear all the injectors clicking. I used my stethoscope to check each injector individually and they all click.

2) I am now very sure that I have a pulse going to Pin 18 from the AB14. I connected my Oscilloscope to the jumper I have connected to Pin 18 and here is a screen shot of what I see on the scope. The spike scrolls continuously across the screen while cranking the engine.

screenshot of scope

I also checked the Fuel Injector harness and the Resistor Pack harness.
Fuel Injector harness has 12v on all 8 pins with Key 'on'
Resistor Pack:
Resistance Reading between 5.7-5.9 ohms. 12v on all 8 pins with key 'on'. Is this what I should be seeing at the plug?

Voltage readings

 

Oh shoot! Awesome, Bro!
start that thang, lol
This is why EVERYTIME when things aren't working for me I NEVER allow my self to say that this and that all checked out with this system and that system - and is okay, lol... I just don't anymore. Tooooo many self inflicted left hooks, lol...some version of GREEN crud, hahaha

This is good!

 

Jay: I think I am getting closer and closer to the finish line.
What I would like someone to tell me is what they see at the Resistor Pack with the key 'ON'
The FI circuit is good. 12v into the injector and 12v out.
My thinking is that the ECU ground signal goes through the Resistor Pack, so if everything is good from the ECU I should see a pulse on the orange wires at the resistor when the ECU provides the ground path to open the injectors but my thoughts have been wrong in the past.

 

V12 GURUS: A couple of questions.
1) What does the TPS WOT test verify?
a) that the injector harness is good.
b) that the ECU is responding to input from the TPS.
c) that the ECU is capable of sending a signal to the injectors.
d) all of the above.
e) none of the above.

If the answer is D, What is my next step?
Does the WOT test bypass the Power resistor?