jiffo

First photo is called the Air Regulator by Nissan. It's simply a cold start/fast idle 12V bi-metallic strip valve which allows idle air to by-pass the throttle plate and flow directly to the plenum, thus increasing idle speed. Engine bay heat will eventually close the valve irrespective of the 12V supply. It's one bit of gear I always block on my Rb's as I find the AAC can do everything I need. If you trace your idle air pipe work, you'll find a tee where the idle circuit splits with one circuit running to the AAC and the other circuit running under the plenum to the Air Reg. (brown plug) Your car also has the idle bump up activated by the aircon. A simple solenoid valve by-passing the AAC and allowing idle air directly to the plenum, thus increasing idle speed. (The solenoid with the purple plug)

No idler on the Toyota JZ engines, although they have a much more heavy duty tensioner system. BUT…..they run a proper cam and crank angle sensor, not like the thing Nissan runs from the exhaust cam. I have a theory that Nissan only fitted an idler as they were experiencing too much timing scatter. Fitting the extra pulley halves the belt harmonic to a level acceptable for most RPM applications. If you're not using an idler, I'd investigate fitting a JZ tensioner instead of the fixed Nissan design PLUS look into a Ross or similar crank trigger setup.

Back to the mechanic. He's stuffed something but without knowing how much he removed, it's all just a guess. Do hope he knew to bleed the cooling system……...

Yes when it's time to replace all those vacuum and coolant hoses, (lots !!!) perhaps service the brake and clutch boosters while you're at it, I think it's engine out. With engine out, turbos are actually accessible too. Rb26 is just crazy complicated and the R32 with hydraulic HICAS, the worst.

The hoses make it impossible to get at, let alone see anything. Truly a horrible mess Mr Nissan.

Probably just the boost solenoid wiring. (Pin 25) Looks like all the difficult stuff has already been done.

Apparently it's not pouring oil out everywhere so probably has the speedo cable still there but just cut off. Should be a keeper plate with a 10mm head setscrew holding that in place. Once the keeper is removed, the cable drive unit will pull out from the extension housing. Do a tooth count on the pinion so you'll have an idea if the speedo is out. R32 should have had 4.3 diff as would the S13 so things should be OK. Push your electronic unit in and fit the keeper plate. Connect up the plug, hope for the best. Your 20 ecu will need a speed signal, wiring been done?

2-thermos plus the aircon fan……..clearance fail.

That's more like it, John. Mine was previously an auto and they have different diameter sender to the manual, hence the machining required on mine. Found out much later that I could have bought an electronic sender to suit the manual box from Adelaide Jap Motorsport.

Not big enough gear. Use a 14lb sledge hammer on the back to absorb the shock. Then your 4lb (min) to do the hit. One good hit will work better than dozens of girly taps.

Are you sure about the mechanical speedo? My S13 had an electronic speedo, as shown in the workshop manual. I had to get an electronic sender machined to fit the Rb20 box.

I see, that's not so hard then. As a temporary measure I'd cut the hose at the burned part and sleeve it with a piece of steel tube/hose clamps until you can buy a suitable replacement. The hose has to take heat and boost so tape won't cut it.

So you're saying the hose end is open to atmosphere? Under idle conditions, the throttle plate is effectively closed and the engine draws air via that black hose. The AAC valve and the air reg are part of that system, which ends by connection to the plenum. This means with an open hose, when idling the engine is eating unfiltered air and when under boost conditions, boost is escaping. It's not too difficult to connect that hose to the "J" pipe as originally intended.

What has been done to the black pipe that connects to that nipple? That pipe connects (via the AAC and air reg) to the plenum so I doubt the engine would run unless the pipe has been blocked.

That's the idle air circuit, AAC and air reg connect here.

Sure you haven't left a rag in the pipework? Most 20 owners have done the cheap 25 turbo upgrade and they go pretty well, my S13/Rb20 certainly did. Noticed a big difference when I swapped back to the 20 turbo. Keep checking.

Auto electricians are expensive as they would have firstly done a trade course and then studied the basics used in modern cars trucks, campers you name it. They'll have a working knowledge of engine management, charging systems, aircon and so on. You can't expect to understand all this without proper training and Youtube, Google etc will only bury you with useless info. For your situation, (a re-power) I suggest you study the wiring diagrams of both vehicles so there's no surprises when you tackle the job. Ask questions on their forums and soon you'll have that required knowledge.

Is this the model?

As you've pretty well ruled out the clutch, I'm thinking it's a worn box. The k's quoted may not be true so try a test and report back. Drive the car in 2nd and hold the stick hard into gear. Accelerate/back off a few times and feel how much the stick moves against your hand. Do this in 3rd, difficult trying 1st as the car accelerates too quickly but give it a try. With a worn box, you get excess end float in the main shaft. You'll feel this through the stick as the shaft tries to move forwards/backwards due to the thrust from the helical gears. You can reach a stage where the shaft moves too far and even though the synchro has worked, the result is tooth on tooth so you simply can't select the gear. You may find selecting 2nd is a no-go and 3rd is OK but with a crunch. (2nd has gone tooth-on-tooth while 3rd has moved too far away for correct synchronisation)

Moderately difficult to access.

I wouldn't panic until the battery is fully charged, these cars are very sensitive to low battery voltage. See if the fault occurs once she's fully charged.

Yes not that difficult, but I found breaking other items was the worst part, boot release for example. So whenever I'm working on/under/around the dash, out come the front seats first thing. Then unbolt the boot release as the handle is flimsy plastic and if you accidentally sit on it, she'll break. Toss in a few bags of rags to lie on and I'm ready to go.

Pin 43 will receive a 12V positive input to the ecu, when the IGN key is turned to the start position. I'm not understanding your problems, thread has wandered a bit since the initial question so perhaps you could give us an update of where you're at now.

Pin 43. Start signal to starter solenoid. (when IGN key is turned to the start position)

You got a start signal? Timer gets re-set at each start signal.