CG13 Mystery Non-Start Issue

Hi all, I have a CG13 from a 99 micra in my mini (pretty much the full micra harness too, incuding NATS, but with all the non-engine bits cut off), been working brilliantly for a few months. But a couple of days ago I tried to neaten up the wiring a little (not removing anything, just tucking it away a bit) which did involve taking the ECU off and back on again, as well as disconnecting the battery for a while. Since then it wont start, it has spark, and there's fuel in the rail. The ECCS relay is turning on, and there is power to ECU pin 46 (I believe the injector supply, but could be wrong). Code reader doesn't display any errors, the light on the ECU stays on all the time. Instinctively it feels like a NATS issue, but it doesn't start at all, unlike the usual second or two then die that the immobiliser gives. Really not sure what else to check, was hoping someone on here with lots more experience than me might be able to help!

Thanks in advance,
Tom

does it run with a drop of fuel down the t/b tom ?

frank said:

does it run with a drop of fuel down the t/b tom ?

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Hi Frank, thanks for the reply, it does indeed, fires straight up

if there is a live to the injectors then it does look like a nats problem then eh

urgh, bloody NATS! have you ever seen it play up like this without an error code showing? Wondering if something has forgotten its code or something while the battery was disconnected. Is there a reset or resync sort of procedure? Thanks

probably best to fit a pre nats ecu and swap the pinouts mate
cas and fuelpump wires iirc

It couldn't be a dodgy earth or a broken connection or wire as it was working before? I've not played with NATS so don't know how it plays up though.

checked all the ECU earths and the NATS transponder earth, all good. Really wanted to keep the immobiliser if I could, and it was running just fine! though if it does this a lot (and these issues do seem common...) it might be best to bin it

still, if I've no choice, Frank, what year does NATS start getting fitted? or at least an easier to bypass version of NATS. Also will a 1.0 ECU work for a 1.3? as there seem to be more of these around. Thanks!

the first 2 or 3 years were pre nats or nats1 tom (same oblong ecu)
and i ran 1.0 ecu,s on my 4 x 1.3 k11,s

Right, in a rare occurrence for these, its not NATS! swapped to a pre-nats ecu, swapped all the pins, and its exactly the same. Suspected the cam sensor, but its earths and 12v feeds are ok, and the signal has continuity to the ECU. The ECU to injector wires are all ok, and there's 12v on the injector feeds, which seems to pulse a bit when actually cranking the engine. Still feels like I must have knocked or dislodged something while I was fiddling, but I cant see anything obvious. Any thoughts on what else could be causing this? I'd really appreciate the help!

have you tried a noid test on the injector wires tom ?
a 12v feed, but no earth signals from the ecu is usually nats

If you still have both keys and standard ignition you can reset with the keys.
fit key 1 and turn on for10 seconds or so, remove and repeat with key 2 within 10 second.
resets NATS and should be good to go.

Does this need doing on a pre-nats ECU? As I've now swapped the ECU to the older pre-94 ones, with the same symptoms.

Did you also swap the pins on the ecu connector? The pre nats has some pins on another place (Fuel pump and ignition if i remember correctly)

I ended up going for a Fusion ecu as I was cutting out so much Including the ignition switch. But the key shuffle kept it going until I swapped it out.

yep, swapped the pins over as per the diagrams (cam sensor, fuel pump and a 12v feed), fuel pump is working correctly etc. Is there anything else anyone knows of that might stop the injectors firing? bad ground somewhere?

since it was only since you altered the wiring tom, it may be 1 of the earth wires ?
the sensors have their own earths to avoid any "noise" eh

the prenats earths are different too iirc (pinout swap)

sensor earth is my current theory Frank, (great minds!) I'm suspecting the cam sensor, since the ecu reader is showing the TPS and MAF sensors giving sensible (to me anyway) values. Planning to strip away to the shield and see if its grounded. On the earth front, the diagrams look the same to me, but does the pre-nats ecu needs its outer case earthing maybe?

Thanks for the help all!

if it still runs with a drop of petrol with the prenats oblong ecu tom ? then maybe not the cas

yep, quite right Frank, CAS shielding is connected to earth, and the car still runs with fuel down the TB, so back to square one. I'm fairly certain that either the ECU cant connect the injectors to ground, or its getting a bad signal from somewhere and so its not opening them at the right time. Think it might be time to multimeter every ECU connection through to its end

have you definitely got fuel pressure mate ? if a noid light works ok it can only be that

I'll admit I did have to do some googling to figure out what a noid light was, dont have a proper one, but shoving a micra sidelight bulb holder on some wires in the injector plug gives a pulse at about the frequency you'd expect. Although it was a little faint, so maybe not much current there? I plugged in a spare injector, and I couldn't see or hear it operating. Fuel pressure could be an issue, I dont have a gauge, might have to invest, could the regulator have stuck open? I tried giving it a little tap with a screwdriver and it didnt seem to change anything.

fuelpipes on backwards is a common non-start problem