3b s2 coupe resurrection

[andy10v]

Cylinder 1 coil plug

Pin 1 12v
Pin 2 earth continuity
Pin 3?
Pin 4 earth continuity

[twoqu]

The coolant and IAT!
Power and earth at coil plugs as well?

[andy10v]

I have 12v from the old coil feed.
I have earth at the old coil earth (plus and earth onto the cam cover)

[andy10v]

So we are now looking at sparks!
Wonder if you have somehow interchanged the two sensors connectors. Doubt whether that would stop it starting.
Start with power to the coils.

Yes, sorry

Which sensor connectors?

[twoqu]

Not sure how John's (or indeed others who have converted to COP) but I have seen it done by taking a power feed off the alternator to a relay and triggering via the original coils feed.

[andy10v]

Injectors ok, operator error

Steve was kind enough to have a chat with me on the phone, I did not operate the throttle when doing an output test Injectors click after the throttle has been opened.

So I would now appear to be missing spark, now checking the dizzy hall sensor wiring

brown/yellow wire has continuity to the intake manifold
red/black wire has 5V
green signal wire has continuity back to the ECU

[twoqu]

So we are now looking at sparks!
Wonder if you have somehow interchanged the two sensors connectors. Doubt whether that would stop it starting.
Start with power to the coils.

[andy10v]

A spare ABY ECU arrived today courtesy of Alex, still no start.

No fault codes except G28 engine speed sensor.

Output tests all work except injectors, no noise from them.

Coolant temp and IAT are at -49 in measuring blocks.

Span it with the MAF unplugged, pulled out plugs and they are wet and stink of fuel!

[andy10v]

I think what Andy means is using the post on the pillar to test continuity for the injector earths, through the chassis

[twoqu]

Ah! Good idea!
It does mean that the after run pump earth connection is a good candidate for ground in the engine bay!

[Error404]

I think what Andy means is using the post on the pillar to test continuity for the injector earths, through the chassis

[twoqu]

As I tried to explain above, the large brown ground cable that goes to the A pillar has nothing to do with the grounding for the ecu or its sensors, despite being in the loom! It is for the after run pump and relay as far as I can tell. It does not go back to any pin on the ecu connector.
If you need any info on the loom, let me know as its far easier to examine off the car than on, especially single handed.

[andy10v]

That is great info, thank you for taking the time to do that, I will double check continuity back to chassis.

I should be able to check ECU plug-chassis earth ring in footwell.

I will check the ecu matches your one.

I will hopefully get back at it tomorrow.

[twoqu]

Right not sure if any of this helps but...
Essentially the motronic loom has 5 earths/grounds. Only 4, the ones that go to the inlet manifold end up back at the ecu connector. The fifth which is a larger one goes to the A pillar. This appears to be connected to the after run pump and relay and not the ecu as such even though it is in the engine bay/Motronic loom.
So that leaves us with the 4 which go to Pins 10, 14, 19 & 24.
Pins 10 & 19 are on one ring terminal and Pins 14 & 24 are on the other. There is continuity between the shared pins which is to be expected as they share the same ring terminal!
In the wiring diagram its states that Pins 10 & 14 are connected at 17 earth point on inlet manifold. Pin 19 is connected to 138 earth connection (control unit) in Motronic wiring loom. Pin 24 to 84 earth connection engine block front right wiring loom. Which is a bit odd as we know that we know they are paired together!
This leads us to the ecu itself. It seems that various pins are interconnected in the ecu itself which helps to explain the grounds for the various sensor that terminate in Pins 30 and indeed 48. Pins 14, 19, 24, 30 & 48 all have continuity between each other. Pin 10 appears to have a connection but has a measurable resistance, at least on the ecu I probed!
So Pin 30 and Pin 48 would be grounded only if the ecu is fitted I think through the internal connection to one or more of the other grounds.
It does highlight that the ecu is entirely dependent on the engine for its grounding so the engine to chassis grounding is an important consideration!

[andy10v]

Ah, got you now.

I will check that tomorrow, I have run an extra ground strap from the IM to the chassis when I put the engine back in last year.