Hi all, I've got a spare ecu allegedly from an RB5, which runs fine in my 2000 classic/ GC8 wagon, and with *plenty* more midrange punch.
However it won't idle properly, revs sit at 1200 or so whether warm or cold, and it hunts slightly ie up to 1300/ down to 1100.

This looks like an air leak problem to me, are there any major differences with the RB5 induction or idle-air setup that might cause this?

The car is bog standard 2000MY, nothing changed (at the moment...)

Martin

 

and I've only been a member for 6 years, lurker or what?!

 

have you tried resetting the ecu?

look in Help pages on my website Jolly Green Monster - ECU Mapping on how to reset it.

I don't believe there to be a difference that would effect idle.

If you refit the standard ecu does it idle fine?

Simon

 

yes all works fine if I go back to the std ecu. I assumed resetting wouldn't do much since the RB5 ecu has been on my garage shelf for 6 months!

I'll give it a try and report back...

thx
martin

 

if the original ecu was fine.. you fit the rb5 one and it is playing up it could be that the original ecu learned to a failing maf for example.. the rb5 ecu is then fitted and in a reset state..

if you refit the original now and it runs fine then something else is occurring

Simon

 

other possibility is fuel pressure - was RB5 any different to standard?

 

nope same.