rb20det starting problems...

[kwazza11]

ahhhhhhhh dont say that!!
fwaaaarrrrrrrrrrrrrrrrrrrrrrrrrrrrrr!!!!!!!!

ok now youve got me worried doesnt the ecu have an ignition relay already?

[kwazza11]

but wait then why would my fuel pump work than just stop like that? it was working a few days ago, i'd get fuel spurting out the line when i put it on ignition

[kwazza11]

ok so i have to put positive to the pump from the ignition switch through a relay and positive to the relay and the earth to the ecu pin #18 to switch the relay and give power to the pump yeah?

[kwazza11]

and does this mean i've wired an ignition feed directly to the ecu fuel relay earth pin?! there was 2 white wires on that r31 body loom connector! one was silver wire instead of the usual copper. thats the one i wired in to pin #18, #2 on that fastrotor diagram of the r31 main body loom you posted on my last thread, the one next to the speed sensor wire

[tandy ass]

Originally posted by kwazza11
ok so i have to put positive to the pump from the ignition switch through a relay and positive to the relay and the earth to the ecu pin #18 to switch the relay and give power to the pump yeah?

OK if you've wired pin 18 to a relay then you'll most likely be OK

If you wired the ignition wire to pin 18 then you'll have problems.

Pin 18 is what is called a "current sink output" which means it has a transistor inside the ECU which goes open circuit when its switched off and short circuit to ground when its switched on. If you have 12 volts on one side of the coil of a relay and the other side of the coil to this input, you will be fine, so long as you've ensured that the relay is diode protected for back-EMF and the diode's Anode is pointing to the ECU and Cathode is pointing to the 12v supply. If there's no diode it could possibly damage the ECU from the back-EMF, I dont know if it will but rumours exist that it can. If you get the diode the wrong way, its effectively like you've put the 12v straight on pin 18.

[kwazza11]

well thats the question i guess, i wired up the r31 (rb30e) "fuel pump cable shield wire" to pin 18 but looking at the factory wiring diagrams for the r31 i cant really tell if the sender is a relay or the circuit for the fuel sender.

[kwazza11]

well regardless i'll do that tomorrow. dick smiths would have diodes right?
i'll wire in a relay and fingers crossed everything works.
just to clarify:
i take ignition feed off the back of the switch and feed it through the relay to which wire on the fuel pump?

theres a green(?) wire from the fuse box to the fuel pump, i take it this is the old rb30e's power supply straight off the battery. theres a black and a white from the sender to the body loom connector by the ecu. the black looks like it connects to an earth circuit and the white to pin 44 on the rb30e ecu. so does the white wire provide a signal to tell the ECU the fuel pumps on, or does this wire get earthed through the ecu like the r32.... but then if that was the case it'd be working! ahhhhhh
jesus the more i think about this the more i get confused!

[tandy ass]

I dont remember... All I remember was the fuel pump wire was a single wire which had two conductors, an inner and an outer... it was a year ago when I did it....

[kwazza11]

ok i had a look today and appears that the r31 DOES earth through the ecu. because when i earth the white wire out when theres ignition power the fuel pump whirs into life!
but i also checked the resistance from pin 18 when ignition is on and it doesnt change at all!
could me earthing pin 30 have something to do with this?

resistance from pin 18 is 15.2 kiloohms and doesnt change on ignition. could i have fried something making this resistance? or is this how it earths

[kwazza11]

on ignition the white wire from the fuel pump has 12 volts, but i guess it has to be earthed to switch a relay to turn the fuel pump on. SO this means either the 12v from that wire has done something to the ECU or the ecu is finding a problem from a sensor and not letting the fuel pump provide the engine with fuel!

[kwazza11]

Things i've wired up in the past few days that could cause my ecu to not want to give me fuel:

ECU pin #30 = roughly translated (throttle sensor and engine sensor) ground. i earthed to chassis.

ECU pin # 44 = neutral switch. wired to neutral switch on 5 speed. also earthed black wire from neutral switch to chassis

ECU pin # 53 = car speed sensor. wired from old rb30e signal

could any of these affect the ecu turning on the fuel pump?

[tandy ass]

Follow this diagram:

http://members.optushome.com.au/piss...r33english.jpg

The ONLY wires that should be connected to the chassis are pins 116, 108, 107, 10, 20, 50, 60. Maybe pin 30 but the diagram doesn't say. If the loom is wired that way then it is so, the diagram leads me to believe it is that way.

Neutral switch - Dont wire in.

Speed sensor - Dont wire in.

Wire ignition +12v to one side of the coil of a relay. The other side of the coil goes to the ECU. This means the ECU does NOT switch the fuel pump on/off directly, it switches the relay which switches the fuel pump.

Wire the +12v ignition wire to the fuel pump +ve wire directly. Ground one side of the NO (Normally Open) contacts of the relay and the other pin to the wire going to the fuel pump negative.

[kwazza11]

ok update on things. i wired up the fuel pump the way you said bozz and it started... well almost, it started but wouldnt idle and would stall straight away! if any throttle was applied it'd cut out instantly!
so i thought about it awhile, and thought i'd try unplugging the AFM and she starts and idles and boosts! so i'm guessing a gimpy AFM so i'll get that changed over.

one last problem though, it seems to have pre-ignition or something as it runs for 5-10 seconds after the key is turned off!
surely these engines dont have inbuilt turbotimers?

[tandy ass]

If it runs for 5-10 seconds after you turn it off, I'm led to believe that somethings been wired a bit incorrectly with the ignition circuit, perhaps the ECU still has power after you turn the ignition switch off but it switches the fuel pump off so the engine will run till it loses fuel pressure.

Pin 58 should be connected to the battery (via a 15 amp fuse of course)

Pins 45, 49, 58, 59, 109 should only have 12 volts on them when the ignition switch is on the "ON" and "START" positions, all other positions these pins should not have 12v on them.

Check that and report back

[kwazza11]

woooohoooo!
just took it for a spin and im pretty damn happy!
god damn the wastegate is noisy when theres no exhaust :p

replaced the AFM and put clamps on the cooler piping.
one thing i noticed while i was at the importers (went to a different one than i got the engine from) is that i didnt get an overboost sensor (?) with the engine. is this necissary? can i use its fitting in the plenum for a boost gauge? as i'd really like to know whats going on inside the engine.
also my turbo outlet pipe was different.. 50mm opening instead of the 60-65mm one on thier rb20det! there were a few other small differences i cant remember.
could they have given me a nics rb20det with a few r32 bits and pieces??
what are the differences between these engines? i'd like to know if these guys ripped me off.

i think your right about the ignition power staying on there bozz. i'll test it tomorrow after work as its already dark and i dont have any portable lights...