Mk3 Cavalier Owners Club | Vauxhall Cavalier Dot Com

Okay after picking my backside up off the floor from shock.

There are actually two looms in there.
Both look in need of a miracle to make either one of them usable.
(Thankfully I am defibrilator trained).

I have decided that I need to totally depopulate the proposed ECU plug of it's pins.

I took one look and thought - you are out of your depth here Rob...
But a brew and a sandwich soon calmed me down.

Just the task of removing 50 wires.
Only two have let go without a fight so far.
Belling out and labelling anything that doesn't move,

Repair any damaged wires and plugs.
I have found one of each so far.

And then assemble / reconfigure.
Before loom taping and posting back.

I am allowing until the end of March for this.
Fingers crossed.

Started nice and early today.
The hardest part was motivating myself to begin.

So here is what I had to start with...



Plus one damaged wire. Possibly caught on the bulkhead at some time or other during fitting, transfer, or removal of the loom from one of the three cars that it had previously been fitted to.



Quickly repaired and soldered.

I noticed that the casing had been broken at some point.



So this meant that all the pins needed to be removed.
Vauxhall have long since stopped using fully enclosed cable entries

My trusty 1.4mm jewellers screwdriver was not cutting the mustard...
So I had to modify one of my pin extraction tools.
This worked brilliantly.



The whole connector was stripped of pins in less than 15 minutes.



The three connectors that fit down by the central locking module and the fuel pump relay all looked okay.
So just a quick loom up to keep them tidy.

Only got this far -



Some research needed to identify which connector is which -
Two sensors have identical colour schemes.

Grey / black,
Grey / red
Brown / red

Get those two sensors clarified, and then we are on the home straight.
(UPDATE - I was mistaken, one sensor has brown/green for its ground shield. Confusion over.)

Only about ten or so wires to re-make, modify or repair.

About 6 ground wires, a diagnostic wire and a couple of sensor wires.

That is next Sunday accounted for...

Okey dokey...

So I finally compiled a full list of wire locations, based on the TIS technical documents.
The schematics are a bit confused.

So here is my list



And here is the loom sprawled out on my settee.















I am keen to get this finished, but trying to force myself to wait until Sunday.

That is gonna be bonkers! You really should Youtube this stuff Rob, you'd make a mint!

There is nothing to show really.

Only the smoke and sparks coming from my ears when I am working this stuff out.

Other than that, I am sure one loom looks just like any other.
The joy of this is seeing the various stages through to completion,
And hopefully being told in a month or two, that the car actually runs.

Aaghhhh!!

Why did Vauxhall use the same connectors for several sensors on the ECU loom.

As I do not have an X20XEV for reference, I am struggling to identify which connectors do what.
The lambda sensor is easy as it is the only one of that shape.

The coil and the MAF sensor use the same 4 pin connector - but I can tell those apart as the coil only has 3 wires.

The air intake temperature, coolant temperature and some others use the same 2 pin connector, but the plugs are different colours.
I sort of guess the blue plug is for the coolant temperature sensor.
The brown plug and the white plug.... hmmm.

Then there are the three pin connectors..
Crank sensor, hall sensor and Camshaft sensor.

My head hurts.

I had repaired all but two wires...
Threaded the loom into the connector housing,

And fitted 2/3rds of the pins before realising that something wasn't right.

Time to put the damn thing down until Sunday.

UPDATE -
I think that I need to separate some wires, and add another ground tag to one of them.

I also recognise the red 2-pin tank vent valve connector.
It is the same as on my C20NE.

I know I missed something in my list....
There are 14 connectors plus the injectors.

I'm starting to forget why you're doing this, what's wrong with just using the cavalier standard ecotec loom?

They are unable to find a suitable ECU - Simtec 56.0 or 56.1

Only Vectra-B Simtec 56.5 ECUs appear to be available these days. His old ECU had apparently died a death.

Anyway - I think I finally have it sorted.

Just missing one wire from the inlet solenoid valve.
I am assuming it is batch-grounded with other modules via a single pin on the Cavalier...

But - Y19 Inlet Solenoid Valve is shorted via it's own pin (53) on the Vectra-B.

So a few more checks to do.

UPDATE / CORRECTION.
There is no inlet solenoid valve (Y19) on the Cavalier.
That is that solved.
Hopefully it will not trigger the engine light on the Vectra-B ECU.
It is an electronic valve like the EGR, not a sensor.

The loom is finished.

What a total cow to get the ECU connector cover back on.
50-odd wires take up a lot of space.



The sensor loom plastic conduit was just crumbly, so I used some conduit from the donor loom to replace the crusty original one.



All bagged up, and boxed, and ready to go...

Nicely done, happy with it? Or will it be more of a relief when fitted and working?

It is a relief that it is finally done.
Albeit two weeks earlier than expected.

It pickled my skull a few times decyphering between models, and Simtec versions.

Oddly - although the looms were both from a Cavalier, the colours matched the Vectra-B schematics.

I will be 100% happy if the car starts and runs...
With or without the 1110 diagnostic trouble code for the missing Y19 Intake solenoid valve.

Beyond the wiring, it is in the lap of the gods...
I have done my bit, to what I hope and think is correct.

The last of the calibra ecotecs are similar, I think they ran out of parts and started using vectra parts.

The report so far is.

No start, but it is cranking fine.
Immobiliser is working fine - EML no longer flashes.
Getting fuel.

So it sounds like the ignition side of things.

I believe he is considering a new coil pack and crank angle impulse sensor.

But yes, it seems like the loom itself is working fine.

Okay - update to this so far.

He is getting spark,
And fuel to the injector rail.
But it appears that the injectors are not firing.

The engine fires and runs briefly with easy-start...
So it is a fuelling issue.

Now then, I assume Crank Angle sensor controls the sparks, so that must be okay.

So what controls injector timing?

Camshaft Position / Hall Sensor
and / or
Knock Sensor.

Although further thought suggests that the knock sensor retards the ignition to reduce pinking.

Can I consider the issue to be the Cam position sensor?

Knock sensor only retards the iginition.

The cam sensor is supposed to control it, but not stop it working, if the cam signal is there then it times the injectors, and without it then they just fire whenever accoding to the engine speed. Or thats how the older motronic ecus worked.

Are you getting 12v at the injectors?
The second relay of the fuel pump relay powers the injectors.

I am still discussing remotely.

I have told him to check for voltage to the common live terminals of the injectors - red/blue wires.

And also check for a triggered ground on the ECU controlled ground pins.
These wires are all brown with a coloured stripe.

A small 12volt LED should work for testing purposes.

He is away this weekend, so probably nothing now until next weekend.

Lord knows what Siemens Simtec do... they are a law unto themselves.

Bosch Motronic do at least seem to stick to a set pattern or formula.

I don't know if it's relevant because I don't know the age of the donor engine or loom, or anything about electronics for that matter

The x20xev's for cavaliers required a camshaft sensor modification consisting of a sensor with a differently shaped plug and trailing wires for soldering to the original plug wiring. I couldn't tell from the pics if this had been done or if it was a later loom.

From what I understand, the loom has been used successfully on two previous cars,
(Owned by the same couple).
but it is definitely NOT third time lucky in this instance.

At the moment things have gone quiet...
But I know that his wife will message me as soon as they get the car going....
Or they scrap it out of frustration

I thought the reaon for the plug was it changed to a different type and they stopped making the old

Yes the plug changed,
So they allow you to cut and shut the wires.

I wonder what they do about the screening, especially as the join is usually made at the rear of the plastic cable conduit.

I know the crank angle sensor was very vulnerable to electrical noise, so I would expect the Camshaft / Hall sensor and Knock sensor to be just as easily affected.