Thread: Low idle

The stepper should always aim for about 650-700RPM and it sounds like its working if the idle with Ac on is higher.

I suggest you clean around the throttle blade and the oil vent outlet into the throttle area with carb cleaner. Also clean the stepper cone and its seat.

If that doesn't work next step is to set the Kerb idle at about 550RPM, To do this block off each end of the stepper bypass hose ie the stub on the throttle body and the stub on the stepper housing, and loosen the grub screw you will see on the top of the throttle body. This is a bypass.

It should fix it just by cleaning and make sure you clean the throttle blade itself as well as the throat in the vicinity.
Gee an easy one!
Regards Philip A

Originally Posted by PhilipA

The stepper should always aim for about 650-700RPM and it sounds like its working if the idle with Ac on is higher.

I suggest you clean around the throttle blade and the oil vent outlet into the throttle area with carb cleaner. Also clean the stepper cone and its seat.

If that doesn't work next step is to set the Kerb idle at about 550RPM, To do this block off each end of the stepper bypass hose ie the stub on the throttle body and the stub on the stepper housing, and loosen the grub screw you will see on the top of the throttle body. This is a bypass.

It should fix it just by cleaning and make sure you clean the throttle blade itself as well as the throat in the vicinity.
Gee an easy one!
Regards Philip A

Thanks Philip,

I'll give it a crack tonight if I get some time.... I haven't broken the car for nearly two weeks, so I better do some more tinkering

seeya,
Shane L.

Ok, I whipped the housing off that contains the idle stepper motor so I could see what I was doing. Just like everything else under the bonnet of this car, it looks clean and like it's been apart in the near past and checked. Everything looks checked and replaced, wiring, hoses, radiator .... It one of the things that stands out when you lift the bonnet.



I just gave it a quick wire brush with a soft stainless steel brush and sprayed down the guts of the drive with some silicon spray. Note: the washer broke up as soon as I unscrewed it. fortunatly my bag of leftover orings and gasket has a slightly thicker version in the exact size (it'll be fine the stepper motor should just drive the drive out a fraction further).





Note: the metal tag sitting out on the housing that has chopped up the last seal. I just ran a file over it to level it.

It does seem to idle much more nicely now. I guess we'll see next time it's good and hot if it's made any difference though.

OK , but the main reason for slow idle is that the throttle plate gets dirty and therefore reduces the amount of air that passes it when it is just cracked, so make sure you clean it also.
Regards Philip A

This is one thing that's annoyed me since the first time I lifted the bonnet:





This looks absolutely ****house.... It'll be the gas fitter that did this. You can clearly see the intake leaks at the air cleaner connector and where that breather hose attaches.









How could the gas fitter allow this to leave his shop like this. Anyone that sees it is going to say "whatever you do don't use XXXXX for gas conversions".

I'll need to move the air cleaner and sensor 1/4" further forward so the rubber flexible bit fits in there with the gas mixer ring.... I'll need to somehow fix up that ****ty hole slashed in there for the breather too. (I'll get my uncle to checkout how the rest of the gas has been done just to be on the safe side when I next see him. He retired about 2years ago, but specialised in gas conversions for about 15years prior to that).

shouldn't there be a rubber seal between the sensor and air cleaner housing ?

[img]



Wow ... Look how HUGE the intake restriction is from the gas

That would have to make a big difference to both gas and petrol performance The weird bit is it seem to run really nicely .... I would have thought that would kill performance.

Has any tried a BLOS carby to get rid of the huge inlet restriction ?

http://www.aussiefrogs.com/forum/red...2F320994547616

seeya,
Shane L.

So the low idle is on petrol or gas?

If on gas the stepper will have not have the same effect unless there is a feed in to the petrol ECU.

It will still raise idle for aircon as it opens a set step for aircon on, but probably won't control idle as it cannot change fuel/gas input only air and that depends on how well the gas is calibrated.

In the gas case you will have to open up the air bypass , then probably your aircon step will be too high.LOL
Ah the beauty of gas.
Regards Philip A
And look at the dirt in the intake! There should be an oring between the MAF and aircleaner. Boy what a crap job.

Originally Posted by PhilipA

So the low idle is on petrol or gas?

If on gas the stepper will have not have the same effect unless there is a feed in to the petrol ECU.

It will still raise idle for aircon as it opens a set step for aircon on, but probably won't control idle as it cannot change fuel/gas input only air and that depends on how well the gas is calibrated.

In the gas case you will have to open up the air bypass , then probably your aircon step will be too high.LOL
Ah the beauty of gas.
Regards Philip A
And look at the dirt in the intake! There should be an oring between the MAF and aircleaner. Boy what a crap job.

Pretty sure it's both petrol and gas. I'll have to check. It's only done a few thousand kms since the gas was fitted (see how it's all shiny and brand new) ... Next job is to clean the throttle butterfly (I'm pretty sure I can see it shiny in the piccies above ) ... to be honest though, I can't believe this is all 280,000kms old. Everything is remarkably clean. Someone has fixed this up in the distant past (distant time past I'd say, but not a lot of miles ago).

seeya,
Shane L.
PS: I don't reckon that'll be dirt there.... look how HUGE the breather hose is ... surely that can't be right, shouldn't it have a metering orifice at the end of it ? ... it'll be crankcase fumes/oil residue