Idle-control valve?

[dazza]

You don't need an ICV, your problem is the tune forg

If you don't have an ICV then your idle will be dependant on 2 things, 1 is the idle function on the ecu (fuel, ignition) and 2 is the little screw on the TB which should adjust your idle?

So yes I imagine at least "some" air needs to get through the TB regardless

[Captiva Fan]

Originally posted by dazza
You don't need an ICV, your problem is the tune forg

Smurfy; ask something the right way, and you'll eventually hear what you want to hear.
Tune is much easier to fix than addition of extra hardware. :D

[dazza]

It's something that should be considered to add later IMO just to make the car run a little nicer cold and under electrical load it's defintely not somethign you need

[Ben Wilson]

Originally posted by Forg
What if you're not using an ICV?
Or is that not an option?

Fit a choke??

[Charlie]

You'll certainly need the tb cracked open if you're not getting air in any other way forg, doesn't just idle on nothing :p
Without the icv you 'may' find you'd have to set the idle higher than you'd like for normal driving, so that it's ok with a cold engine at night with the air con on.
________
IOLITE REVIEW

[Zac]

What about that big plastic knob/air bypass that resides under the throttle body on the K-Jetronic setup? Got that?

[gtst4]

Got this from another forum, but check the PCV valve is working correctly.

[Captiva Fan]

Yeah, the valves to the PCV system are all fine; there's nothing fancy there 'cos it's a 1980 car. I'll have to look for knobs, it's actually an LH-Jet throttle-body, but I vaguely recally there's still asjustable knobage of some description.

[Ben Wilson]

Without some sort of idle control, it either won't run happily whenever it is cold or it will idle at around 2000. Could there be some sort of passive water temp control in the TB like old 4AG's used to have?

[Captiva Fan]

There's at least one bloke in the US who's got an injected B230FT in a 242, and he hasn't got an idle air control valve installed; but he hasn't got aircon either. B21E's apparently had a switch on the TB that operates with the aircon to get around that issue; I may have to look into it. Also, my cam's probably a tad more aggressive than the majority of turbo Ovlovs, and I expect that'll make it less happy to idle smoothly as well.

[Com_VC]

Originally posted by Forg
I thought some cars just idled by having the TB not shutting completely when at idle?

I thought that it would have to be fully closed when at idle? I know thats the case with my VK EFI setup. If it's not fully closed maybe look at the throttle cable setup.

Also that pic that zac posted is an auxilary air valve, basically allows the engine to idle while cold. It is not ecu related. Should just be connected to switched 12v. Do you have anything like this?

[dazza]

How is the engine going to get air at idle if the tb is fully closed?

There's no other ways in unlike a VK

[Captiva Fan]

More on this, and remembering that the ECU tune is completely UTS; I can't get the car to start without the throttle being open a smidge (which makes sense), but once the throttle is open even a teensy bit I suspect it's open enough for the engine to suck in enough air & even create a teensy bit of boost (it's not going into positive boost, but it's getting close to 0 psi) ... that's feeding the engine, and the only reason it's not going past 3000rpm is, I believe without necessarily being right, because that's where I set the rev-limit in the computer.

Does that extra info give anyone who's already commented any more idea? It seems to me like maybe I do need some form of idle-control valve; but frankly, I have no idea of where to physically fit it! [The ECU can control it, I'm more worried about where it mounts]


Strange thing is that the amount of fuel going in doesn't appear to be horribly high, despite the absolute guesswork. There's only a teensy bit of colour to the smoke coming outta the exhaust. And the sound makes me smile a bit too, it's very metallic in the way BMW straight-sixes & 911's are, & has quite a noticeable turbo whistle ...

[denmaster]

Forg,

You don't need an idle valve to have the car idle fine. Idle valves are normally used for
a) cold starting
b) compensation with other load inducing devices e.g. a/c, slushbox engaging D.

Like everyone says, get it tuned

--lg

[Captiva Fan]

I'll re-use this thread 'cos it's relevant ...

The "surging" problem is a big hole I've left in the manifold, uncovered!! I'll fix it soon,
however,
I'm going back to this idle air control valve thing. The computer will run a pulse-width modulated one, and apparently it'll make the car run much better when cold.
I'm also told that a lot of cars run them.

Now, where do I _buy_ one? I need something that can connect to hoses, rather than screwing into a hole in the manifold that I don't have. Two wreckers just blinked when I asked for one, and the third guy was Just Jap who said to get something locally 'cos they charge import-parts prices. And I don't know what I'm looking for ... I mean, anything can have air hoses going in & out and a couple of wires ...