If i disconnect the IVC with the engine running.......

[TouringMatt]

.........what should happen?

What does happen is......well.......nothing, as far as i can tell. No change in revs, idles the same, revs the same

It buzzes when the ignition is on but not convinced its working right

I've cleaned it out numerous times, does not seem to make a difference

Noticed if i unplug the hose to the fuel regulator it runs like a bitch at idle but seems to rev cleaner, draws a hell-of-a-lot of air too........

Sometimes i feel like giving up

Matt

[Andy335Touring]

That sounds normal to me as i think the IACV will just hold it's position when you remove the plug so the tick over will be the same ? Try disconecting it with the engine running and then turn on all your lights/heater fan/heated window/etc on and watch the revs drop as the altinator starts dragging on the engine. Normally the ECU will sense the drop in revs and tell the IACV to open to hold the revs.

IACV buzzing is normal to.

I've cleaned it out numerous times, does not seem to make a difference

Mine was the same as it was't gunged up enough to play up. What are you using to clean it with ?

Noticed if i unplug the hose to the fuel regulator it runs like a bitch at idle but seems to rev cleaner, draws a hell-of-a-lot of air too........

By disconecting the vac line you are causing a big air leak and the fuel reg will be upping the fuel pressure(more fuel,running rich) as it thinks the throttle is wide open as it hasn't got it's normal vac signal.

HTH

Andy

[Dan318-is]

im with genius ^

[TouringMatt]

Thanks for the explanation

I've been using Wynns Carb Cleaner, lovely stuff

I'll try the full electric load test and see what happens


Cheers
Matt

[Andy335Touring]

Carb/brake cleaner is the right stuf, you hear some folks using WD40 which isn't good

[Brianmoooore]

Early ICVs closed themselves when disconnected (stalled motor turning against a spring).
Later ICVs used a balanced arrangment between two sets of coils, and stay put when disconnected.

[TouringMatt]

Did some testing, started the engine and disconnected the IVC, then switched on as many electrical item as possible. Revs wents from 800 to 600.
Reconnected the IVC and the revs stayed as they were - thats not right is it?

Cheers
Matt

[Andy_magic]

When you say the idle stayed as it was do you mean 600 rpm.

The best way I have found to test ICV's is to run the engine with it connected and stick it in 1st gear and ease the clutch up to put some load on the engine, keep easing the clutch up a fraction at a time until there is obvious torque load on the engine, dip the clutch and the engine should breifly increase and then return to normal.

The ICV will not be able to compensate for an incorrectly set butterfly though. With the butterfly open too far the ICV can't slow the engine down enough, with it shut too far the ICV has to open too much to keep the engine idling.

I have seen many a car with the throttle butterfly opened up to sort out hunting idle, yes it sorts the idle out, kind of, but usually knocks the TPS out of adjustment.

The throttle butterfly gap should be 0.75mm and is measured by taking the AFM - TB runner boot off and look for a gap at the side of the thottle butterfly, set with feeler gauges and reset the TPS.

HTH

[TouringMatt]

Yeah, i plugged the IVC back in and the revs stayed at 600rpm

I've tried that 1st gear test, in fact i changed the ECU thinking it was the problem, so re-tried that test after fitting and the revs just dipped to about 500rpm, pushed the clutch in and the came back to around 800, no rise

It did this on both ECU's which to me ruled them out as the fault...

I actually checked the TPS/stop gap last night, at 0.2mm i could here the switch click, but at 0.4 i could not, so its that gap too small?

I did have the TPS off to repair it so it could possibly be out

I take it that 0.75mm is the stop screw gap, not the physical gap between the butterfly and the TB wall?

Cheers
Matt

[Andy_magic]

ooerr.

The 0.75mm is between the butterfly and the wall of the throttle body, I don't think there will be a clearance between the adjustment screw and the throttle lever whassitsname.

[TouringMatt]

Andy, im going to go set/check that gap in a bit, at 0.75mm, should the TPS be heard to click or not?

Matt

[Andy_magic]

Hi Matt,

I've checked my motronic setup guide and the gap shouldbe .5mm - .75mm, the TPS will need to be reset after the adjustment is done so that it clicks when just coming off closed throttle. Hope that helps

[TouringMatt]

Nice one mate

I'll let you know how it goes

Matt

[Andy_magic]

heres that guide I wrote.

http://mysite.wanadoo-members.co.uk/e30/motronic.pdf

Let me know if its any use, it's not pretty but it might help you out.

andy

[TouringMatt]

Im stuck!

I've set the butterfly to wall gap at 0.75mm and screwed the stop switch in ( is this right, because that means the butterfly never ever fully closes? ) but i cant get the TPS to click and its turned as far as it will go
I have to screw the stop screw out a few turns to get TPS to click



Matt

[Demlotcrew]

I would have never touched the butterfly!

See if you can find a new throttle body. You might also have a intake gasket leak or your AFM is playing up.

Andrew

[Andy_magic]

I don't really understand that comment demlot, care you elaborate?

The way I see it these cars were put together in the first place, so they should be able to taken apart and re built.

The throttle body adjustment, is just that, an adjustment, if it wasn't meant to be adjusted it wouldn't have an adjuster. Adjustment Adjustment

I'm guessing the guys car isn't a brand new one that has delivery milage only, it's probably had a few owners. If it isn't running right it needs everything checking out and every potential problem sorted.

The trouble is most people don't know as much about cars as they think (Not aimed at anyone on here, aimed at previous owners etc)

They twat about with adjustments for things like idle and it screws other things up, like TPS positions etc in a quest to get the car to idle blah blah.

By ruling out faults introduced by well meaning nofcukalls such as increased air gap in throttle bodies etc you have base, firm settings.

The 0.75mm gap as mentioned in my guide was taken from BMW literature, however it may not have been for UK cars as I sourced it on the internet. The general idea is that the butterfly doesn't shut tight against the wall of the throttle body.

If anyone would care to get the exact process as written by BMW for sorting out poor idle I'd be happy to host it.

But yes, you could go and buy another throttle body off a scrapper, will the gap be right, will the TPS be shot, will it need setting up, will it need a clean.

[Xhawk]

Im stuck!

I've set the butterfly to wall gap at 0.75mm and screwed the stop switch in ( is this right, because that means the butterfly never ever fully closes? ) but i cant get the TPS to click and its turned as far as it will go
I have to screw the stop screw out a few turns to get TPS to click



Matt

Well obviously u have to adjust the TPS, so that in the present stage of the TB, it clicks when u open the throttle.