I have an earlier post about installing a rebuilt engine and problems with both the ignition harness and the fuel injection harness. It has finally gotten cool enough to work on the car again.

With the ignition on, I am not getting power to the fuel pump.

I verified power to pin 86 (White Wire from Ignition Feed) of the Main Relay, pin 30 (Brown Battery Feed) of the Main Relay, and power to pin 87 (Pink and Black wires) of the Main Relay. I then verified power to pin 86 (Pink and Black wire) of the Pump Relay and power at pin 85 (Orange wire routed to Pin 15 of the EFI connector plug.

I verified power to Pin 30 (Brown Battery Feed) of the Pump Relay and at Pin 87 (Brown and Gray {Slate}) wire that feeds power to the fuel pump and to the Brown and Slate wires of the O2 Sensors. I am not getting power there. If I pull the Pump Relay and install a jumper across Pin 30 and Pin 87, the pump runs.

I pulled the cover off the Pump Relay Bosch 0332014 113 but did not see an issue with the contacts, I am going to install the relay with the cover removed tomorrow and verify that the relay closes. I suspect that the issue is at the EFI ECU. I pulled the connector and with the ignition on measured voltage at each pin as listed on the attached chart.I am not sure how to check the ECU. Perhaps someone on the forum can look at the voltages and suggest where to look next.

 

Before getting too far into the weeds......

Just to clarify.....

The most you should get from the pump when turning the key 'on' is about 2 seconds of operation. Then it stops.

Are you not getting this 2 second prime?

Does the pump operate with the key turned to 'start' ?

Cheers
DD

 

With Doug on this.

I ALWAYS earth that Orange wire, independent of the ECU when trouble shooting this. There have been a few over the years.

That removes the ECU Timer Earth Circuit from the Pump Relay, and that pump should RUN whenever the Ign Switch is in the ON position.

If that sorts the thing, then the ECU Timer Circuit is the issue. NOT common on the 16CU spec units, but it can/does happen.

 

Maybe this helps someone.
My 1989 V12 XJS ran fine until one day last week. I had loaded groceries into the trunk, got in car, it started. I backed up about 1foot and it died. Could not get it restarted and had to have it flat bedded back home. Thanks to Grant for all the great knowledge, I started checking the easy stuff. Still no start. Today I reread about the orange ground wire at the pump relay and went to check it. What I stumbled on was the White Wire connector on the EFI RELAY to the Orange/White Wire on the inertia switch had separated (apparently bumped while putting in the groceries). Reattached the connector and VAAVOOM - up and running.
-

 

Doug;

I climbed in the trunk and had the Mrs. turn the key. Doing so, I got the short prime you mentioned. I put a Noid Light on 1A injector connector and had her turn over the engine. Light flashed. I also had a light installed on A2 spark plug. I don't seem to be getting a spark though.

Grant; good tip about grounding the orange wire.

I will focus on getting spark. This is a Marelli ignition car.

 

I should have mentioned that pump ran with key in start.

 

Well, I am still fighting with this.

First up, I found that I had two wires crossed for Coil A (Marelli Ignition Digital Ignition Fig 30.1) which were the two WN wires. I swapped the connections at the connector and now have spark. I had repaired this harness and must have swapped the two wires during the repair.



I tried connecting the Orange wire at the pump relay socket to ground as suggested by Grant Francis, but the pump did not run with the ignition on. So, I checked the inertia Switch and found the red button popped up, so I pressed it down and now fuel pump runs with the orange wire connected directly to ground with the ignition on.

I can press the contacts closed on the pump relay with the relay cover removed and the pump runs, but having the MRS try to start the car, no injectors click and the Noid light that I have installed in the 1A injector connector does not flash. So, I am thinking there is a fuel injection issue (?).

I want to check the voltage from the white wire at pin 24 of the ignition ECU which goes to pin18 (Engine Speed Signal) of the fuel Injection ECU.Is that a simple voltage check?

I am open to suggestions on what to look at next.

 

I give it a shot I guess...

So, where you're at now, you've reconnected the orange wire to it's OE state and when you turn the key to ON (not started) you do get the 2sec prime - pump runs? If your partner cranks the engine (even though it doesn't start) does the pump run?

If you turn the key to ON (not started), everything as it should be, do all injectors CLICK for you IF you quickly turn the throttle cap (center of the VEE) to WoT? All injectors should/will give an audible click with this test.

One step at a time is best.

Above, what I thought you'd said (correct me) is that you do now have spark, a pump that runs rightly and injectors that flash a noid light - fire?

 

JayJagJay;

Thanks for your suggestions.

So I took the jumper wire off the orange wire that was connecting it to ground. I had the Mrs turn on the ignition and I did get the two second prime.

However, when cranking the engine, the pump did not run.I don't understand what changed from my reply to Doug on 9-23-21 at which time the pump ran while cranking the engine and now.

With the ignition on I turned the Throttle Turntable to full open. The injectors did not click. I used a mechanics stethascope pressed against 6B injector and then again against 4B injector just incase I did not hear the click. I did not seem to get a click..

I do have ignition spark.Once I fixed the wires having been swapped for the four pin connector for the A bank coil, that problem seemed to be resolved. I have one of those spark testers inline with 2A spark plug and wire. It flashes when turning over the engine.

I am not getting the noid light flash this time. I do not know what if anything changed between my reply to Doug and now, other than the inertia switch having been popped. I checked the Inertia Switch just to make sure that it had not popped again. It had not.

 

I'm sorry to say that what goes on with those relays, main and fuel, is still a bit of a mystery for me. I still have a lot to learn. Also how much some, if not all, of that comes into play with the ECU... I do have a couple of suggestions and hopefully someone will correct me if I blunder.

One idea is as much of a question as anything else. What I understood was that YES, you will get the 2 second prime at key turn BUT, that does not mean that the pump will run, injectors will fire and the plugs will spark when the starter cranks the motori UNLESS there is a signal that the engine is spinning coming from the sensors that sense the rotation,,,,

That (I think) has to to do with the 2 crank/fly wheel position sensors. Have they been looked at an made sure to be one, good!? and two, at the right distance from the front crank - right under the front crank pulley wheel... and (I know this was true on mine) the second sensor at the LH bottom of the bell housing is not damaged or melted, or mounted improperly? It can get dangerously close to the first curve in the downpipe/intermediate pipe connection, and can melt! etc...

I think if you use Google and the forum you can get specs to test these two sensors. Both plugs can be found under the hood,,,, one right in the area of the pig snout, front of LH cam cover area, near the LH fuel injector, near rail... The other plug usually hangs around on the LH side near the fire wall and balance pipe - back of engine. Test for continuity at least.

Hopefully someone will chime in with right resistance values for these two sensors.

 

To review, Car has been on jackstands for several months. Earlier on, after replacing the EFI harness with a used harness that I had traced each wire on before it was installed. Initially, I was getting injector pulses. I was not getting spark. I ended up repairing the ignition wiring harness (this is a Marelli ignition car). The harness had sucumbed to heat and while the wires were intact, most insullation had crumbled and fallen off allowing wires to cross short. I took the harness out and systimatically cut each wire one at a time and sliding heat shrink tubing over the wire and then adding a crimp connector which was then soldered and covered with heat shrink.

I had looked to replace the harness, but one was not available and to buy one was about $2,600 and I would have had to send the existing harness for them to use as a pattern.

I was still not getting spark and discovered that the two WN wires at the A Bank coil connector were reversed during the harness repair. I swapped the two wires and now have spark. Looking at Figure 30.1, both magnetic sensors (one reads the teeth on the flyweel during engine start and the other called TDC sensor reads the three fingers on the crank damper), rulling out the sensors as having anything to do with the EFI. W wire from pin 24 of the Ignition ECU sends a signatl /voltage to pin 18 of the EFI ECU according to Figure 25.1..

So, If I am getting the two second fuel pump prime, but not the pump running with the engine turning over, my thought is to check the white wire at pin 18 at the EFI ECU. My question is, what am I supposed to find? Is it simply voltage with the ignition on? Does the voltage pulse or change to tell the ECU engine speed? I have a spare EFI ECU and will install it to rule out something being wrong with the EFI ECU.

Suggestions?

 

You wrote:
"Looking at Figure 30.1, both magnetic sensors (one reads the teeth on the flyweel during engine start and the other called TDC sensor reads the three fingers on the crank damper), rulling out the sensors as having anything to do with the EFI."
I know nothing about Marelli engines; but are you sure that this is true?

 

When you crank the car over does you tach needle jump around!? It must. If not, indicator of a bad or mis gapped CPS...

 

Oh and, from your last post, I believe you need some sort of oscilloscope to get an accurate reading on what's known as the Dreaded White Wire aka DWW... Again, it is the signal from the CPS sensor which comes over this wire... It sends a wave-Y signal to the ECU. If pin 18 is the DWW feed that is. I'm not looking at a wiring chart at the moment.

If you were messing around with the loom on the LH side of the engine, between FI 4 and 5 in working on coil wiring it is possible that the DWW was disturbed...? Ground left off?

 

Didn't see this covered, but maybe simple like a pinched fuel line or hose or fuel filter backwards.

 

So, I examined the white shielded wire that connects between the Digital ignition harness near the throttle turntable and the EFI ECU. The wire is a shielded wire with the shield connected to ground. The wire insulation was cracked and a few of the strands were broken. If the wire was flexed it shorted to ground. I corrected that problem and then confirmed continuity from pin 18 of the EFI ECU and pin 24 of the Ignition ECU. With the ignition turned on, there is 0.17 vdc at pin 24 if the Ignition ECU and also 0.17 vdc at pin 18 of the EFI ECU.

So it appears that I now have connection between the ignition ECU and the EFI ECU. That said, when I attempt to start I am not getting injectors clicking and the Noid Light installed at in the injector harness at 1A is still not flashing.

Suggestions?

The photo shows the EFI ECU harness wire disconnected and showing the cracked insulation and the wire shielding.

 

What I think that I've come to understand is that the wire IS shielded over the long term because it's such a low voltage that all kinds of interference can be carried to the ignition* (edit - meant FI) ECU... BUT temporarily, for testing purposes, a length of thin wire can be run directly (well, around and outside of the car) from the connector to the ECU completely cutting out the shielded wire. In this, you can see if the shielded wire is the problem... Repeat, I think... Just make sure that it's a "clean" connection.

 

There is a 'plug' on the positive battery cable with two connector wires. Make sure they are both cleaned and firmly seated. If not, the pump won't work. At least that was my experience.

 

I started reviewing again "So ya got a HE V12 that won't start'. I had a spare Power Resister pack and unplugged the connectorfrom the existing Power Resistor and plugged it into the spare Power Resistor. I had the Mrs. crank the engine, but still no injectors clicked. I tried rotating the throttle capstan to open with the ignition on and still no click. I have a spare TPS and a spare CTS and will swap each out tomorrow one by one.

 

A thought.......

The EFI ECU, pins 16, 17, 34, 35 "Injector Grounds"....

Are these pins showing ground? The wires to these pins ground at point "G6", RH side of the trunk

Cheers
DD