resetting ECU on Vn

[vnbelina]

hi guys i was wondering how to reset the ecu on a vn. the reason is i have noticed my idel be very rougn and thoruht if i reset the ecu the idel will be redone. if this is possile once i reset the ECU do i turn the car on and give is high revs or just let it idel to fix the problem
cheers

[jack.mc]

From memory you disconnect the battery for a few minutes, then rev to 3 grand for 10 secs. Or leave the battery disconnected for ages does the same thing i think

[sircruisealotVS]

either disconnect both battery terminals or remove engine fuse...then take it for a spin for all the sensors to send new info to the ecu.
this wont neccessarily fix your rough idle problem though.

[mouce]

Uh...why disconnect BOTH terminals? Just the earth will do fine.

Leave it disconnected for 30 seconds (minimum) reconnect, and rev and hold 3000rpm for 10 seconds.

This resets the IACV, and because the battery has been disconnected all the error codes from the ECU are wiped too.

NOTE: if you have a cold engine when you do this, wire it all up, start it up and let it idle for a couple of minutes, disconnect, reconnect 30 secs later THEN rev it. That way you aren't revving a cold engine.

[vnbelina]

cheers guys very helpful t
thanks

[sircruisealotVS]

Uh...why disconnect BOTH terminals? Just the earth will do fine.

uh..because its dangerous to only take one off...do you really want a loose current that cant be earthed running around.

[sp001in]

uh..because its dangerous to only take one off...do you really want a loose current that cant be earthed running around.

what the **** are your talking about current from ****ing where? the magic current fairy??? not earth means no earth. dah

[defa]

i am with sp001in. either one you take off will incomplete the circuit and there is now power

[sircruisealotVS]

current from where you say....well if you took you head out of your ass you'd know a battery carries a surface charge...even when the negative is taken off the terminal.
and if your screwing around within your engine bay and you have an incomplete circuit because you've taken the negative off..then there's nothing to filter the surface charge off the battery and keep it from jumping to anything that may come in contact with the positive terminal.
this is when potentially dangerous surges can happen.
it pays to play it safe.

[coolkenny]

i reckon u should leave the earth(or negative) post on and disconnect the positive, ( or both ) for resetting the ecu

[samuels]

Uh...why disconnect BOTH terminals? Just the earth will do fine.

Leave it disconnected for 30 seconds (minimum) reconnect, and rev and hold 3000rpm for 10 seconds.

This resets the IACV, and because the battery has been disconnected all the error codes from the ECU are wiped too.

NOTE: if you have a cold engine when you do this, wire it all up, start it up and let it idle for a couple of minutes, disconnect, reconnect 30 secs later THEN rev it. That way you aren't revving a cold engine.

i don't know how many times i have said this,you DO NOT rev your motor for 10 secs...it's just not nessacary....especially a cold motor.once power has gone from ECU,upon reconnecting it,start car NORMALLY the ECU automatically detects any variables and adjusts accordingly.

[samuels]

what the **** are your talking about current from ****ing where? the magic current fairy??? not earth means no earth. dah

technically still has current flowing thru...,thats why they say disconnect A battery lead AND engine comp fuse when resetting ECU... to avoid damage to ECU

[mouce]

i don't know how many times i have said this,you DO NOT rev your motor for 10 secs...it's just not nessacary....especially a cold motor.once power has gone from ECU,upon reconnecting it,start car NORMALLY the ECU automatically detects any variables and adjusts accordingly.

If you read the post properly I actually explain how to get around reving a cold engine. And yes it's true that the ECU will detect everything, including an idle air control valve that is still settling into a new position, so it doesn't get a true 'fix' on idle. In the code which is hardwired into the ECU there is a trigger engine speed at which point it readjusts the IACV into the best position.

If you don't need to rev your engine then congratulations to you, but I, and most other VN/VP owners follow what Holden recommend, and what the Gregory's manual recommends as well. I know that in my one, and the other ones that I've worked on, that idle is much worse than normal (and that's saying something), if they do not have the IACV reset the way that Holden recommend.

I'm not out for a fight, I'm just going on what I've found.

[samuels]

If you read the post properly I actually explain how to get around reving a cold engine. And yes it's true that the ECU will detect everything, including an idle air control valve that is still settling into a new position, so it doesn't get a true 'fix' on idle. In the code which is hardwired into the ECU there is a trigger engine speed at which point it readjusts the IACV into the best position.

If you don't need to rev your engine then congratulations to you, but I, and most other VN/VP owners follow what Holden recommend, and what the Gregory's manual recommends as well. I know that in my one, and the other ones that I've worked on, that idle is much worse than normal (and that's saying something), if they do not have the IACV reset the way that Holden recommend.

I'm not out for a fight, I'm just going on what I've found.

well congratulations yourself...just for your scrap book holden don't recommend that you rev at 3000 rpm,and iv'e never seen a technician YET do it
PS ... i'm not out for a fight either...

[mouce]

well congratulations yourself...just for your scrap book holden don't recommend that you rev at 3000 rpm,and iv'e never seen a technician YET do it
PS ... i'm not out for a fight either...

Okay, I'll keep that in mind. Cheers. It's just that the Holden tech that I speak to occasionally has said that it's recommended that it gets done. I guess it's like all information that comes out of Holden, there's a few different versions of what is 'recommended practice'. I often wonder about how many fights would start if you got a room full of Holden Techs and asked a simple question. none of them seem to say the same thing to two people

[greenfoam]

I've changed memcals thousands of times in mine and never had to rev it to 3000 rpms for 10 seconds yet, it just runs a bit wonky for a few seconds and then it's ok, the IAC must reset doing other things besides being reved

[Emackulation]

Interesting theory Foamie. If any1 has needed to rest his ecu sensors n stuff it would be The Foam cuz he is always changin memcals for diferent applications. But me myself found that after i started my motor when i just put in a new gearbox it was running SHIT and even stalled, then kicked her ova again revved to 3k n she was perfect again.

[samuels]

Interesting theory Foamie. If any1 has needed to rest his ecu sensors n stuff it would be The Foam cuz he is always changin memcals for diferent applications. But me myself found that after i started my motor when i just put in a new gearbox it was running SHIT and even stalled, then kicked her ova again revved to 3k n she was perfect again.

maybe thats because you didn't give it time to re-set...a run around the block usually does the trick...but anyrate you did what you probably was told,but theres absolutely no need to rev your motor to 3000RPM...doesn't sound to pretty with no load on engine,and customers don't like it if they are around (revving their car @3000RPM aimlessly

[Emackulation]

It stalled, thats how rough it was running haha. I had to floor it just to keep the engine running lool.then turned her off and back on again she was good. hehe.

[stocky]

i reckon u should leave the earth(or negative) post on and disconnect the positive, ( or both ) for resetting the ecu

leave the negative on and pull the positive off? are you nuts?

[mouce]

It stalled, thats how rough it was running haha. I had to floor it just to keep the engine running lool.then turned her off and back on again she was good. hehe.

WOW, I've never had mine run that rough before a reset. That's gotta be a fairly extreme case.

Next time I may try just letting it find its own settings again. I'll drive it around for a bit and see how it comes up. Hey...I'll try anything once.

[Emackulation]

Hey...I'll try anything once.

Except guy on guy i hope....

[mouce]

Except guy on guy i hope....

Yeah...okay...fair call.

That's something I've been offered, but I did decline that one. Didn't even think about it. Girl on girl...well...

[VNPOWER]

It stalled, thats how rough it was running haha. I had to floor it just to keep the engine running lool.then turned her off and back on again she was good. hehe.

I had the same problem when i took my throttlebody off, the car was running really bad, stalled a few times, did this until i kept it at 3000rpm for 10seconds then it was all good.

[Doctor Bob]

after powering down the ecm, the revs need to be over 2000 for 10 seconds to reset the IAC, these are both variables that can be set in the memcal.

Rob