ECU missing 12 wires...

[NewKleer]

Ive found the wiring job done on my rb25 silvia wasnt the best, heres a list of the wires the ecu is missing. perhaps they may relate to fuel consumption problems?

5, 14, 15 (DT1, DT2, DT3 signals from Auto) - not needed as manual car

17 - Injection pulse (Ti monitor) signal

19 - Power steering oil pressure SW signal

21 - RX Receive (consult)

22 - TX Transmit (consult)

25 - Boost control solenoid sig

31 - CLK (consult + anything else?)

33 - Exhaust temp warning lamp

44 - Neutral SW

47 - CHK (consult)

53 - Vehicle speed sensor

56 - Throttle opening output signal

57 - Exhaust temperature sensor signal

104 - Fuel pump terminal power control output signal

now the problem is finding these wires and getting them hooked up. are there any i should leave? any that seem desperately serious? aside from fuel consumption, had i never checked the ecu i wouldnt have realise so many are missing.

[cameron]

17 - Injection pulse (Ti monitor) signal

19 - Power steering oil pressure SW signal

21 - RX Receive (consult)

22 - TX Transmit (consult)

25 - Boost control solenoid sig

31 - CLK (consult + anything else?)

33 - Exhaust temp warning lamp

44 - Neutral SW

47 - CHK (consult)

53 - Vehicle speed sensor

56 - Throttle opening output signal

57 - Exhaust temperature sensor signal

104 - Fuel pump terminal power control output signal

QUOTE]

Doesnt wire 53 destroy the speed cut ?

That carnt be good with thoes conncetions missing ...:bonk:

Maby another ecu harness ?

[NewKleer]

yer the 53 one probably doesnt matter

the harness says something like "r33 5mt series 2" or something. main problem with harness is that its missing the pins to put on the wires to insert into hardness - can u get these elsewhere?

the ecu has this on it. i didnt see any leds on the back near the screw:

P5 (barcode here)

Nissan 23710 21V02

MEC-R522 | A1 | 4516

Hitachi Ltd, Tokyo Japan

Made in Japan

on the side (or the plastic film on back near screw, forget) it had:

MEC-R522 | A1 | 0016

what ecu is this? normal r33 s2 manual ecu?

[blind_elk]

The most common cause of high fuel consumption is located at the end of your right leg.

You don't need any of the "consult" wires (21 22 31 47) - they are for the Nissan diagnostic tool.

You don't need 53 - 180kph limiter

Probably don't need 104, unless your car has the hardware associated with this wire.

You can probably get away without 19

56 is an output - I know it's for the ATTESSA system in 4WD models. Also for Auto Trans. You probably don't need it.

Not sure about the "engine temp warning" wires - but I'm running an aftermarket ECU without this function, and it seems to go OK.

[predator]

some of those may be related to cold start cycle though, which may harm fuel economy.

one of the main causes of bad fuel economy is generally a ****ed O2 sensor, but it wouldn't suprise me if 56, 57, and 104 also are used by the ECU to regulate things.

[paulr33]

bad fuel economy, you should check the 02 sensor and its wire to the ecu.

the oxygen sensor is the same part thats used in the ford ea falcon, around $120 part and should be replaced after 40,000kms according to nissan service manual, when its dead it doesnt give correct feedback to the ecu regarding fuel and lean mixtures. the single purpose of the 02 sensor is to tell the ecu to save fuel and nothing more

the boost sensor wire is only required if you are using the factory rb25 boost solenoid. if you are using the rb25 stock boost solenoid youll be stuck in 5psi until you connect this wire to the ecu (will goto 7psi over 4500rpm) or you can constant ground the wire on the solenoid and it will be in 7psi mode all the time

[NewKleer]

btw ive replaced the o2 sensor with that el ford one, and it did bugger all for fuel economy (from ~17l/100kms to 15-16L/100kms). i want to get consult happening so that can help diagnose further, but it wouldnt have anything to do with fuel economy. i hardly push the car at all, so can rule out the right foot from the equation. will have a longish drive on the weekend down to wollongong so that may help checking out consumption on longer drives.

im running 10psi with bleed valve, not sure what that means in regards to boost sensor. im assuming im using the factor boost solenoid...

does my ecu seem like the normal one?

[k43]

hey buddie ive done that conversion before and just now im doin a rb20 conversion wich is heaps silimilar those things that are missing shouldnt be the problem. and 10psi boost wouldnt be the stock boost solanoid. who done the tuning on your car that could be the problem with the fuel consumption.

[NewKleer]

u cant really "tune" the car at all, just ensure everything is operating correctly. ill be taking to a dyno, probably after i get consult working and can check any other things.

on a seperate issue, i seem to have gone from 1 noisy exhaust lifter to add another 2 noisy intake lifters D:

[NewKleer]

i talked to mark at hills motorsport and he said something along the lines of the speed sensor for the r32 gearbox i have, is interfacing fine with the s13 dash, just it wont interface with the ecu due to being sine vs square waves, and id need some converter that might cost a lot.