Can someone explain to me the logic behind the idle speed?... (N/A Jap '92)

 

On cold mornings before the engine warms up there seems to be different idle speeds... circa 2000rpm, then down to something around 1500rpm, eventually settling out around 900rpm once warm... On warm days, or on returning to a still warm engine, the idle speed is around 900rpm...

 

Anyone of the resident experts care to explain whats supposed to be happening?? :)

 

Thanks in advance

Dave

Engine speed is increased by the ecu when cold to improve fuel atomisation - once everything is up to temperature the ecu lowers the revs. 900 is still too high though - you need to adjust your base idle setting ;)

Thanks.

 

700rpm seem reasonable.... how? Is the sytem adjusted by mechanical endstop somewhere or potentiometer somewhere?...

 

Dave

To set base idle - remove yellow connector from back of idle valve (rear pass side of plenum) and turn the screw on the side until the revs are ~700 rpm (think thats right for an NA?), reconnect the yellow connector and sorted ;)

My revs are pretty high when warm too. Any chance of pointing me to a diagram or something? no idea what idle valve or plenum is.

 

Cheers.

Plenum=big metal thing on top of the engine - kinda looks like a rib cage ;)

oh yeah I knew that! ;) So am I right in thinking I'll warm up the car then remove this yellow thing then turn a screw till the revs go down to 700?

 

Are the revs actually going down when I do this or is it just the reading on the revometer?

Yes, the revs should go down as you adjust the screw. You should also make sure the TPS is set right too as that can confuse things.

Tps?

Throttle position sensor - black box on side of passenger side TB ;)

Ok this could go on for a while but....

 

TB?

Throttle body maybe?

Yup - sorry ;) Just post so much I don't wanna wear my keyboard out with long words :rofl:

fair enough ;) How do I make sure th tps is set right then?

Voltmeter or conZult ;) You need to find someone to do it for you - preferably about 100 miles away ;):rofl:

datascan won't do it then?

Yeah course :)

cool I got that. Although the program seemes to have taken itself off my computer.

 

Ok thanks for all this I'll have a play over the weekend.

Voltmeter or conZult ;) You need to find someone to do it for you - preferably about 100 miles away ;):rofl:

PMSL :rofl: :rofl: :rofl:

Of all the post whores on here , I nominate Mr Andrew Duff for the award of best mix of facetious . insulting , humourous , provocative posts . But this is all well-balanced by the amount of solid and sound advice he offers in between his drink-sodden declarations ( allegedly ) , which of course appeal to me personally , in my role as a saviour of the fallen .

:tongue:

:duffer: :duffer: :duffer:

Alright , I`m not as sober as I was at , say 6pm...who is ffs ?

PMSL :rofl: :rofl: :rofl:

Of all the post whores on here , I nominate Mr Andrew Duff for the award of best mix of facetious . insulting , humourous , provocative posts . But this is all well-balanced by the amount of solid and sound advice he offers in between his drink-sodden declarations ( allegedly ) , which of course appeal to me personally , in my role as a saviour of the fallen .

:tongue:

:duffer: :duffer: :duffer:

 

faecetious ;)

 

So you sayin I'm a clever pisshead? :rofl:

faecetious ;)

 

So you sayin I'm a clever pisshead? :rofl:

One of the cleverest of all ! :smash:

One of the cleverest of all ! :smash:

You and Gazza ( the former footballer , as opposed to Gaz , the former Hellraiser ) :rofl: :rofl: :rofl:

lets not forget his mate ten bellies or however many bellies it was that he had. But yeah, fantastic excellent adviceAndy cheers. maybe now I'll be able to use data scan for something other than watching the dials go up and down as I depress the accelerator.

 

Oh yeah one final thing, I take it I check the tps before I do any adjusting of the idle revs?

You and Gazza ( the former footballer , as opposed to Gaz , the former Hellraiser ) :rofl: :rofl: :rofl:

 

Erm not sure how to take that. Glad you enjoyed your beer :rofl: I certainly enjoyed mine ;)

Alfo, yes. Its likely I'll be back in wolves at the weekend, you can bring it round and i'll sort if if you like.