StuartTheFish

But like I say, I really wouldn't think it's the speed sensor itself at fault, since the speedo works.

The power steering will work at first, since it assumes you're parked, so just gives full assistance. But after a while it realises you aren't, and then goes into failsafe mode.

In that case, pass. :( It'd be one hell of a coincidence if it does turn out to be both clusters with the exact same fault. Whereabouts are you? I'm in Harrogate if you fancy a road trip?

Yeah, and do the same from the clocks to the ecu too, since you said it couldn't see the signal either.

Have one probe at whatever pin it is from the cluster, and the other probe on the relevant pin at the ecu and then hicas control unit. Then see if it still beeps.

If there's no continuity, then you will see resistance. It's continuity you need to be checking for, so you want NO resistance. ;)

Don't know, someone in an earlier post said the chimes stop with a UK speedo anyway, and I've got a UK speedo so never had to look into it. I guess you could just unplug it, the chimes would come from that top box in the first picture.

You don't disable the converter, you physically remove it, then join a couple of wires back up. Take the tape off and it should become clear.

The converter is the smaller one on the bottom right of your first picture. And as said, the zedworld cluster also has a converter hanging off it.

You'd need an oscilloscope to do that I think, to monitor the pulses. But if you've tried a different cluster already, then it shouldn't have an issue there. One hell of a coincidence if that is the issue!

Unless I've read the diagram wrong on that page, it appears to be pin 6, in the larger wiring plug. It shows the layout of the plug in the middle of the diagram.

Page 67 fella. :)

Here you go, not sure what page it'll be on, but it seems to include wiring diagrams: http://300zx-twinturbo.com/cgi-bin/manual.cgi?list=st&dir=&config=&refresh=&direction=forward&scale=0&cycle=off&slide=29&design=default&total=98 Fingers crossed it covers both hydraulic and electronic versions of the hicas. What version do you have by the way?

I'm not sure, but there is a z32 hicas manual knocking about online somewhere in pdf format, so I'll have a look and post the link once I find it.

The hicas light being on once the rack has been removed is normal of course, but the control unit still controls the speed sensitive power steering. Maybe you've disturbed the wiring in the passenger footwell when changing the ecu? Trace the speed signal wire back from the ecu and hicas control unit, and see if you can find a break in the area.

Unless it passes through one unit to get to the other anyway. If that was the case then it could also be a fault with the first of the control units. Like I say, I've not looked at any wiring diagrams to find out, since I don't have any.

If both clocks both do the same thing, then it's not likely them at fault. It's not the gearbox sensor or wiring from it to the clocks, since the speedo works anyway. It'll be a broken wire from the cluster to the ecu and hicas.

No problem mate. The only other thing it could be I think is a loose connection or broken wire in the loom somewhere, and given that neither the hicas or engine control unit are seeing the speed, instead of just one, I'd assume the issue is before it splits and goes in two different directions. That's assuming it does actually split, and it's not passing through one to get to the other. I wouldn't know without looking at the wiring diagrams.

If it's already a UK speedo then fair enough. And yeah the board on the back of the speedo. Not the printed sheet thing on the back of the cluster, but the actual board on the back of just that one gauge. You need to open up the cluster and remove the speedo to be able to get at it.

There's your problem then, now you have to find out why. If your speedo has been converted with a chip, remove it and see if the speed signal returns. Then fit a UK spec speedo so this hopefully doesn't happen again, since converter chips are known to go faulty. If it turns out its the speedo itself at fault, replace it. Or if you're good enough with a soldering iron, look for any dry solder connections and apply fresh solder to them. Could also be a broken wire somewhere in the dash loom, but not as likely as a chip or speedo fault. It's not a faulty sensor, or wiring from it to the cluster, since your speedo is still showing you what speed you're travelling.

Check with consult that the ecu is always getting a speed signal. If it is, then it's an issue with the wiring to the hicas/power steering control unit. If the ecu also struggles to get a speed signal, it could be a faulty speedo or converter chip, since the speed signal goes from the speedo to the various control units. These cars have speed sensitive power steering, where the faster you go, the lower the assistance becomes. If it can't tell what speed you're doing, it'll drop into failsafe mode and apply next to no assistance. That's why it's fine at first, until it decides there's a problem and simply stops doing it.

Can't say I know about the windows 8 issues, but try ecutalk instead of consult free. It works for the ecu, and does datalogging.

As I suggested on Facebook just now, what about using a spirit level to see how far out it is, and then adjust it to get the bubble closer to the middle if needed? That's if you have room to get a spirit level in there of course. Could use your mobile on the top of the wheel even, and use an app.

Good stuff, happy to help. :)

I've got no idea why my phone autocorrected to say breaking instead of braking, well now I look stupid. :(