Vauxhall injection tech question(s)

[JonP]

Hi,

 

Can any body help me with two queries regarding a boggo standard Vauxhall injection setup

 

1) What grades of fuel are referenced by the 'fuel quality' plug...coded A and B current set to B

ie is 'B' correct for 95 octane...if I select 'A' can I use 98 octane to any advantage.

 

2) The idle is fixed by the ECU...but the idle speed is fast, around 1100rpm according to the tacho.

It sounds fast too, so the tacho does not lie....my thought, engine temp sensor is knacked so the ECU thinks engine needs fast idle (and rich mixture?) all the time?

 

Thoughts please!

 

 

 

JonP

 

No longer Sevenless....!

[16vastra]

the a and b plug is not for fuel (knock sensor and ecu do that job) its for noise & emissions regs in norway or summat equally as daft

my cav gsi is set on A where the idle will be 50-100 faster and theres a bit more midrange, nothing drastic tho

you might have a stuck idle air control valve or an air leak causing slightly high idle

might be worth changing the ecu temp sensor yeah as they arent the most reliable things (bout 15 quid from www.autovaux.com) but it would need to be proper shafted for it to control idle speed when hot and you would get starting problems i imagine.

[JonP]

Many thanks 16V,

 

I thought it was strange to have an octane adjustment AND a knock sensor! Just swopped the plug round so the A is now adjacent to the latch mechanism and the idle has dropped by 100rpm as you predicted, so its around 1000 now which is probably within spec given the tachos are never that good. Off to buy some Optimax now!

 

Cheers

 

JonP 😬