The dangerous black knob

Jack91 · 11-06-2009, 07:40 PM

Hi all,

The AU (factory gas ex taxi) had a rough idle so thought Ill clean the throttle body, sure enough it was filthy as and when I was there I thought Id turn (what I thought it was) the idle up. So the car ran ok after wards then went to start it 4 hours later and wouldnt go just kept cranking, FINALLY got it going and it was stalling and just not idling by itself, then I turned it off and heard a KABOOM sounded like I blew the exhaust clean off the block. Anyway, so I dont really remember which way I turned the knob or how many times but I got it going better than it was but its still worse than it was before I screwed around with it. Is there anyway to fix my screwup? And you dont have to tell me how stupid it was, I know now.

Edit - In fact its worse now than it was the 1st time I screwed with it.

Also, because it ahd a rough idle when it was cold is this the culpprit for this too? Or is that some other problem?

XR Lita · 11-06-2009, 08:46 PM

Put up a pic of the little knob. If it is the one I am thinking of, I have played with the one on my car, and it did nothing

chrispie123 · 11-06-2009, 08:47 PM

the black knob on the iac isnt actually a knob its just a housing for a little filter i thought

Mr Hardware · 11-06-2009, 09:40 PM

DavoEF, is this your first time owning an LPG car?

Jack91 · 12-06-2009, 07:58 AM

Yes..

Jack91 · 12-06-2009, 04:22 PM

Ok, problem is now semi-fixed, it was the same deal this morning, not starting, stalling etc so I turned the knob a few turns back and it started and idled fine. But... Then when I went to start it about 8 hours later, same deal with not starting or idleing. So turned it back the other way and fired straight away and idled beautifully. This is so bloody confusing. If I stop it when its idling good and then start it straight away or withing a few minutes its still pretty good, but doesnt like sitting for a few hours. Anyone have ANY ideas?

lofty · 12-06-2009, 04:59 PM

Quote:

Originally Posted by DAVO_EF

Anyone have ANY ideas?

Yep. Like the man said, post a pic of the 'dangerous knob'. The one on the car.

Mr Hardware · 12-06-2009, 07:27 PM

Davo,
Mate there's a few things you need to know to avoid this situation again.
1. I, along with others, are pretty darn sure the knob you are referring to is not an idle screw and you can turn it to your hearts content and it will not change a thing.
2. Do not flood an LPG car and have it backfire on you. You're going the right way for a smashed airbox very soon.
And mate, do us all a favour, and post some bloody pics hey? Put us out of our misery...

The problem you have is most likely not even related to the 'black knob' or the throttle body at all. Chances are your idle jet or whatever it is on your gas converter is starting to bugger up. I'd be taking the car to an LPG mechanic stat for a good bloody overhaul of the converter.

GS608 · 13-06-2009, 07:28 AM

this black knob?

Jack91 · 13-06-2009, 05:30 PM

Yep that one

Jack91 · 13-06-2009, 05:31 PM

It may not be related to that knob, just seems weird that I start the car and wont idle, then turn the knob a few times and it idles.

Jack91 · 13-06-2009, 05:32 PM

And yes I know it doesnt actually adjust the idle, as I said before I thought that it did before I turned it and nothing happened. Obviousely it has something to do with gas flow or it wouldnt make any difference.

JMO · 13-06-2009, 06:57 PM

There is a sort of filter under the black knob as has been said. Maybe that's dirty or clogged and turning moves the blockage??? Don't know how exactly it effects the ISC. Just an idea

Jack91 · 13-06-2009, 07:32 PM

Thats an idea. I missed that post. Im not too keen on pulling the whole t/b apart though. Ive heard that t/b cleaner doesnt work too well with all the little seals and such but should I give it a try?

StealthAu · 13-06-2009, 08:13 PM

I don't really understand why there would be a filter under the black knob. The isc works by bypassing air from one side of the tb butterfly to the other, remove intake pipe and open butterfly and you can see the two holes in the tb which the isc controls flow of.
Maybe try removing the isc and giving it a decent clean

bodes-sh · 13-06-2009, 10:15 PM

you can pull the top off that little black knob, just make sure you don't lose the little filter that's in there. i still can't see how that is affecting it either, but last time i checked mine it did have a bit of dust on it, so it must suck a bit of air in through there.

POELWYK · 14-06-2009, 09:12 PM

Take it to a Gas joint thats what i did and found out my coil pack was gorn so replaced good as new now