BH_SLO32

Spot on!

The light blue wire with the white stripe is the power feed for the heater and light brown wire with white stripe is the heater earth wire (pin115). The shielded wire (quote "One of the wires have like, 2 different wires surrounding the central wire.. ") is the ECU signal wire (pin29). The light blue wire should have about batt voltage when you turn the ignition on. The light blue wire with white stripe should be connected to one of the white wires and the other white wire connected to the light brown wire with white stripe. It shouldn’t really matter which white wire you use as they both connect to the 2 sides of a resister (according to the wiring diagram). I confirmed continuity and a resistance of about 4 ohms. The heater is used to bring the O2 sensor up to temp quickly which is useful on cold starts. The O2 sensor should work without these 2 wires connected. The remaining black wire should be connected to the shielded wire as this is signal wire for the ECU. It is important you connect this wire if nothing else. Hope this helps. Ben

I assume you mean you can't operate the passenger window by the passenger switch. Can you operate the window by the driver side control? If you can, it will simply be a matter of removing the passenger switch and cleaning up the contacts. Fixed this problem more than once. Hope this helps

Waldo, Who did the hi-flow? Do you have the specs from the company? Cheers

Most electronic boost controllers have an overboost safety function where it will lower the pressure once it exceeds a preset value. Have a good look at the boost controller settings in the first instance. Hope this helps.

Who wired up the RB20? What fuel pump do you have? Is it hard to start all the time or only when its cold? If the standard injectors are used there will be no resistor pack as the RB20s have high impedance injectors (as opposed to the GTRs with low impedance and hence the resister pack). `

My Bro-in-law had a generic aftermarket O2 sensor in his 32 and had an intermittent idle problem where the revs would drop and then pickup (if it didn't stall). I spent ages trying to identify the problem and he even purchased another new generic O2 sensor and still had the same problem. I eventually found it to be the source of problem when I could rectify the low idle revs by disconnecting the sensor. Plug it back in and the revs dropped. Replaced it with a factory item and hasn't missed a beat since.

Good news, I believe I found a solution. I purchased a Jaycar “Speedo Corrector” kit and “Digital Tachometer” kit and did some testing in my R32 with RB25. The information provided with the digital Tacho confirmed my suspicions about the required tacho drive signal. The digital tacho can be manually calibrated for 1-12 cyclinder 4 stroke engines. Traditionally the tacho has been driven off the switched side of the ignition coil (primary side) with a pulse generated when any cylinder fires which on a 4 cyl 4 stroke engine is 2 pulses/rev and for a 6 cylinder 4 stroke engine is 3 pulses. Newer cars equipped with an ECU may drive the tacho with a low voltage signal as is the case with most skylines. The number of pulses per revolution has obviously not changed confirming my earlier suspicions that the Silvia tacho is looking for a different frequency signal (to suit a 4 cylinder engine – 2 pulses per rev not 3). I tied into the ECU tacho drive wire and connected the digital tacho which when set for a 6 cylinder engine gave the same reading as my R32 analogue tacho. I then changed the setup to a 4 cylinder input which when idling at 900rpm gave a reading of between 1200 and 1300rpm on the digital tacho (the digital tacho changes in 100rpm increments). At about 3000rpm on the R32 tacho the digital tacho had a reading of about 4600rpm. The speedo corrector kit can be used to correct a pulsed digital signal from a speed sensor to compensate for any speed inaccuracies generated by diff or gearbox changes etc. This would be ideal for R33 owners who convert from an auto to a manual. The unit can also be used to correct tacho pulsed signals. The unit is very flexible as it will adjust the output signal from the unit between 1% to 99% of the input signal with changes in 1% increments possible. It can adjust either up or down. In the case of the Silvia tacho, the drive signal needs to be adjusted to approximately 2/3 of the signal coming from the ECU. To test I set the digital tacho to receive a 4 cyl input and connected the corrector unit in between the ECU and digital tacho. I then proceeded to adjust the corrector unit until the digital tacho read the same as the R32 analogue tacho. I compared between idle and approx 5000rpm. The speedo corrector kit can be purchased from Jaycar for about $45. The kit number is KC5380 (have a look on the Jaycar website). As mentioned in my earlier thread if there is someone in Brisy who would like to trial run the unit then I’d be happy to install my unit in their car. Hope this helps.

If you have a multimeter I can guide you through some basic fault finding? Cheers

The R33 alternators have a larger eyelet connector for the alternator output (B+) compared to the R32's. Simply means you will need to remove the R32 eyelet connector and use a larger one. I think the field wiring is the same although not 100% sure. I believe they share the same rating (80 amps). Cheers

I have encountered the problem several times and find it occurs with Rb20's and Rb25's that have been sitting for a while allowing all oil to drain from the head. When you start the motors again it appears entrapped air below the hydraulic lifter (Rb26's only have solid lifters and shims) or a slow feed of oil results in a noisy lifter. I have typically found that a gentle drive and susbsequent movement of the car always rectifies the problem. Hope this helps. Cheers

Michael, I diagnosed a similar problem on my brother-in-laws R32 and it turned out to be the non-factory O2 sensor. I would suggest next time the idle starts to drop disconnect the O2 sensor and see if the idle rises again. This was a very frustrating problem that took no end of time to find thanks to its intermittent nature and every time I wanted it to play up it didn't - typical! Hope this helps. Cheers

Predator, If you need any assitance with the Rb25 conversion including wiring the new computer, don't hesitate to ask. I'd be happy to assist. I live at Springwood. Cheers, Ben

My own experiences as follows. I have a series 2 R33 RB25DET which in a previous life had an auto strapped to the back and the auto spigot protruded out the front of the crank as shown in the attached photo. As the internal end of the spigot was flush with the crank recess the use of a bearing puller and packed grease had absolutely no effect. Reluctantly and as a very LAST resort I welded a nut to the protruding part of the spigot and wound a bolt into the end of the crank and popped it out. For manual spigots packing grease into the end of the crank and using a 14mm socket works a treat. Cheers

Gents, You have raised my curiosity and I'm keen to find an answer. Given your tachos are actually working I suspect all you need to do is either find an appropriate frequency divider which you connect between the ECU tacho signal output and the tacho itself or install the tacho from an R32. Given the previous motors were 4 cylinders it stands to reason that you need 2/3rd of the current frequency output by the RB ECU ie divide the 6 cylinder freq by 1.5 (6/4) (eg. 4600rpm = 3066rpm). If I had the diagnostics for the any of the 4 cylinder motors I could confirm. I did a bit of a search on the net last night and found plenty of very flash (and expensive) frequency dividers but was looking for something a little more basic. Jaycar sell a digital speedo corrector kit ($45) which allows you to adjust the square waveform of a digital speedo signal (freq only I think) which will probably be suitable for adjusting the tacho signal (also square wave output). If I get the time on the weekend I pop into Jaycar and have a look at the kit. If I think it is suitable I'll purchase the kit and do some testing on my R32 and let you know how it goes. If I get it working I'd be happy to install one in any of cars owned by members in the Brisbane area. Hope this helps. PS Anyone searched the NissanSilvia forum or contacted Tokyo Toys (they specialise in RB conversions for Silvias)? Cheers,

[Also, just about the ECU cutting when you accelerate, it would use the compressor if you have a steady constant throttle right? Yes, the ECU uses the TPS signal and engine revs in the logic to determine when to switch off the compressor. Cheers

I've had a look at the wiring diagram for the R32's and I would actually suggest the 2 wire plug is for the "Active Full Auto AC" and there is no reference to any form of overheat protection. The AC system in the R32s has an auto amplifier which from what I can determine performs some very basic logic functions thanks to monitoring of a number of sensors like intake air temp sensor, fresh air sensor, engine temperature sensor (not the same as the ECU temp sensor) etc. It appears to control the compressor via the additional 2 wires (1 wire is a feed from the amplifier and the other is an earth). From what I have read the cefiros don't have a digital AC system in which case you shouldn't need to connect the other 2 wires. I disconnected the 2 wire plug on the compressor in my R32 and the compressor kicked in fine when I operated the AC in manual mode. Hope this helps. Cheers

Jaik, Sounds like you have found your problem - the pressure switch. The pressure switch will not doubt be used to ensure the compressor operates only when adequate gas pressure is available and protects it if the system pressure is insufficient. I say this because it is a switch and therefore doesn't "monitor" pressure but rather requires a minimum pressure to close. It sounds like thermo fan has some crook bearings and consequently is drawing a high current which no doubt has blown the fuse for the fan (in the engine bay for the R32's). I also suspect the thermo fan is driven purely by the temperature switch in the bottom of the radiator as per the R32 GTS-T and is independent of the AC system. Pin 9 on the ECU is the AC cut signal which will switch off the compressor when you accelerate. Cheers,

Jaik, Isolating the problem is a process of elimination. I suggest you start by checking that power is available at the AC relay as follows. With the key switched to the ACC position you should see approximately battery voltage at either pin 3 or 5. To identify which is pin 3 or 5 remove the relay and turn it upside down. The pins are printed near each terminal. This is the main power feed to the compressor. Next check that approximately batt voltage is present at pin 1 or 2 when the key is turned to the IGN/ON position. This is the trigger wire feed for the relay and is earthed by pin 9 on the ECU. The power feed passes through the pressure switch before terminating at pin 9 on the ECU. The pressure switch should be closed if adequate gas pressure is present otherwise it will open and interrupt the power feed to pin 9 on the ECU. With the key in the IGN position and the AC off, check that power is present at pin 9 (approx batt voltage). If no power is present check that power is present at the pressure switch. If the pressure switch is open power will only be present on one side of the switch implying that there is a low gas pressure or the switch is faulty. If power is present at pin 9 when the AC is switched off, press the AC button and check the voltage at pin 9 drops to approximately 0 volts. This implies that the ECU is earthing pin 9 and activating the AC relay. When the AC relay is switched by the ECU you should hear the AC relay clicking. Now if power is available to pin 3 or 5 as discussed earlier, triggering the relay will allow power to be present at the AC compressor IF there is no physical break in the wire feeding the compressor. If you still don't have power present at the compressor do a continuity check of the wire between pin 3 or 5 of the AC relay and the compressor. If continuity is established and the resistance is low (less than 5 ohms) then further checks will be required which I will discuss separately if required. I don't think you will reach this point without finding a fault earlier in the fault finding process. I haven't discussed the function of pin 46 yet as I suspect it not an issue with the ECU. If you reach a stumbling block along the way give me shout and I assist further. Hope this helps Cheers, Ben

That is correct, throttle body only. Grigor also raised some good points especially about the insulating washers, don't drop them or you could be searching for them for a while. Cheers

I recently fitted some Nismo 555cc injectors to my RB25. Initial attempts to undo the fuel rail bolts without removing anything proved fruitless and I found it was MUCH easier once I removed the throttle body. Access to the fuel rail bolt below the throttle body and the fuel injector plugs is much better. A word of caution, once the fuel rail is free and the injectors are clear, be careful not to hit the end of the fuel injectors on any hard objects as the pintel caps break easily (as I discovered with injector 6). Obviously the same applies when installing the new injectors. I think you will struggle to slide the fuel rail out the front of the engine if the throttle body is in place. Incidentally I am assuming the motor is in the car. Removing the injectors from the fuel rail is easiest done by placing 2 flat head screwdrivers in the slot on either side of the injector and carefully leveraging against something placed under the screwdrivers. Once the injectors are installed (with new O-rings!) you can re-install the fuel rail. I recommend buying a new metal gasket for the throttle body (about $30 from Nissan). Hope this helps. Cheers

I would say the water level dropped sufficiently as to leave the temp sensor exposed to air (ie not submerged in hot water). Cheers

The R34 GTT ECU is quite different to the series 1 or 2 R33 ECU. Differences include a number of additional sensors (eg. boost sensor, cannister purge solenoid) and a variety of additional load sensing signals from things like stop lamp switch, rear defogger relay etc. I suspect the additional load sensing signals have an input into the idle logic. The tacho drive signal is also different to the R33. Hope this helps. Cheers,

Pin 53 on the ECU plug. It should be a yellow wire with green stripe (from memory). Hope that helps. Cheers

I have undertaken the same conversion as BHDave and modified the RB25 loom to make it a 'plug'n'play' loom (ie graft the RB20 body loom plugs into the RB25 loom). In my opinion this is the neatest approach as you can utilise the VCT and boost solenoid which only the RB25 ECU will control. I concur with BHDave's comments re the RB25 gearbox issues and furthermore can add that a new speedo drive will be required and the speedo cable shortened in order to finish the job neatly. I made a custom mount for the RB25 gearbox - refer member gallery. You should consider what power you wish to ultimately achieve with the motor before forking out good money on an RB25 gearbox if the RB20 box will suffice. If you would like some assistance modifying the looms or would prefer someone else to do it, I would be happy to help. I have just finished a loom for another member who is currently putting an RB25DET in his RB20DE Cefiro. Hope this helps. Cheers