GTSBoy

Probably not. A workshop grade scantool is my go to for proper Consult interrogation. Any workshop grade tool should do it. Just go to a workshop.

Well, yes, every CU on the bus is available via the Consult port, but whether the scanner you are using is capable of talking to the TCU, the ABS/TCS modules, etc etc, is what is at question here. Many of them are only for engine codes. So, if you have one of those, you won't know if the ABS is having a bitch.

That's now. R chassis Skylines come from a time when the tolerance in the ADRs was a bit more....slack. My car, on 235/35-17, which is damn near the exact same size as the original 205/55-16, is pretty much bang on correct indicated speed across the whole legal range. That's demonstrated with constant speed run over 5km, and GPS speed. It's just the luck of the draw. My particular speedo head has to be the thing that is "calibrated" that way, because everything else (the diff ratio, the gearbox and the speedo drive**) are all same same as most other Skylines. **OK, so the speedo drive is a Navara unit to drive the R32's cable, not the electronic unit than an R33/4 would normally have with teh same gear on it. Otherwise, I applaud your OCD tendencies, and I would do the same if I needed to.

Does the scanner do all the CUs in the car, or only the ECU?

Correct. Um. I dunno. I haven't cared enough about the way that the NA cars work to know for sure. But..... The 33/34 turbo manual cars have an electronic speed sensor in the gearbox that outputs a +/- (ie, sawtooth AC) voltage signal. That is connected to the speedo. The speedo then outputs a 0-5v square wave (ie, PWM) signal that the ECU (and any other CU on the bus) sees. The speed sensor is NOT directly connected to the ECU. So here's the problem. Your new ECU expects to see the PWM signal, but must somehow be getting a direct signal from the diff speed sensor. Which would suggest that the wiring of the NA car is not the same as the turbo cars. I think you will need to spend some time with (hopefully the wiring diagram for the car) and a multimeter to see what is connected to what. Then, presuming I am correct**, you would then want to separate the ECU speed signal input from the rest of the car's wiring, and probably either buy a speed signal converter, or build one using an arduino (or similar). That would take in the speed sensor signal and output a scaled (and suitably rearranged) signal for the ECU. ** We shouldn't presume that I am correct here, because there might be something else crazy going on. I don't think you could convert the speedo to be fed from the gearbox sensor, because the pulse rate from that sensor is probably different to the diff sensor and then the speedo would read wrongly. And this also wouldn't fix the ECU's problem either, because the ECU doesn't want to see the gearbox signal direct either (assuming that they are all on the same wiring, for some odd NA related reason, see above caveat!) Does this help? Probably not. Can you make it work? Almost certainly. With the above work. You should buy a handheld oscilloscope from Aliexpress so that you can view these signals directly. Connect up the probes and drive the car. Show photos of the screen when drving at known speeds and connected to different places, and we'll see what we can learn about it.

There is no difference between a 17x8 and an 18x8. The total diameter of the tyre needs to remain +/- the same (so you don't mess up the gearing, speedo reading, and clearance when turning front wheels..... so you just need to use a lower profile tyre on th 18 than you do on the 17. /rocket surgery.

I thought the same to start with. But then I thought it was one of those LCAs where the end of the ARB goes through a bushing in the LCA itself, instead of having an end link.

Yeah - I mean, go the other way. Smaller range. Not larger.

And, when measuring and getting <2 ohms, perhaps chose the next larger range than that, rather than something with a k in it!

'sif the ARB does anything on an Astra anyway!

Shouldn't need a "base map" for anything other than guidance to ignition tuning. You just need the engine capacity right, the injector size right, and something, almost anything, for a VE map. On an NA engine, fuelling is almost completely a function of load signal & rpm. It should run and drive with a completely flat fuel map. It will be too lean under load, but that's easily fixed. We used to tune all ECUs without any base map. There were no such things (until someone had tuned a near stock engine on one, and then they had a "base map".

Wanna rewrite all of that in, say, 2 or 3 separate sentences, so that we can read it?

It's almost certainly a reluctor generating an "AC" waveform. No, ECUs don't generally read those - they're usually set up for PWM square wave 0-5v stuff.

If it (the code) wasn't still current, it should have gone away by itself by now. No, nothing it 10/10. But it is quite likely. Everything else to do with the ignition could still be responsible (which is wires and connectors). The car is an old piece of shit now, so all the wires and connectors are also old pieces of shit.

Remember kids - if you can't afford to buy 2 GTRs......

No. I think it might be the AFM. Hence the use of the terms "swaptronics", which implies the use of swapping out electronics for the purpose of diagnosis. It's about the only way to prove that a small/niggling/whatever problem with an AFM or a CAS or similar is actually caused by that AFM/CAS/whatever. A known good item swapped in that still gives the same problem is likely to be caused somewhere else. They're all the same. Spraying AFMs with cleaner is an each way bet between cleaning it and f**king it.

A wise man once told me, "Anything you enjoyed wasting was not wasted".

Have you done 10x restarts since it came on?

Time for some swaptronics.

Just put skinny tyres on it.

Keeping in mind that for most people this is a week to month long job!

This coupled with 6-9 speed autos with ridiculously short gearing is why these modern shitbox cars always seem so fast off the line. If it wasn't for those things, Raptors would not seem fast. The problem we have is there is a driveability gap between a more gentle take off and a wheelspinning sideways launch. The difference between ankle flex required to achieve one and ankle flex required to achieve the other is about 0.5°.

Virtual valve adjustment popping into and out of existence in the quantum foam caused by blowby in the oil.

Hydraulic lifters.

Buy whichever one makes you happiest when you sit in it. After all, that's where you'll be experiencing it.