Idle control valve

90man · 24-05-12, 05:10 PM

As the title does anyone have an idle control valve for a 2.3NG , just finished some messing about with my 90SE, ive fitted new hydraulic lifters, cam belt, water pump, fuel metering head complete with fuel lines and injectors, set it all up and she fired into life instantly, got the timing light on it and adjusted . Took her out for a blast and she runs real good,

but the idle is all over the place , other than that im pleased with the outcome so she,s back in favour again, next is straight through exhaust with a resonator on the end for that good old 5cyl synphony

msh · 24-05-12, 05:17 PM

So what's the problem with idle?

90man · 24-05-12, 05:22 PM

Quote:

Originally Posted by msh

So what's the problem with idle?

Car drives real good but pull up to a junction and she stalls , fires right up , thenext junction it may be revving at 2,000 rpm its all over the place its not a sticking throttle as ive checked it all

msh · 24-05-12, 05:33 PM

Well, ISV can't cause a stall on NG engine, at least when engine is adjusted correctly, because by default when engine is warm, ECU is using ISV to decrease revs - should be around 850 rpm with ISV connected and around 1k with ISV disconnected

I'm currently slowly fighting the fight to get my NG idling properly, might be pot, but ECU isn't supposed to keep the revs up at the first place... And 2k rpm at another traffic light - is your throttle rest point properly adjusted? Maybe idle switch sometimes doesn't work? My former 3A engine kept revs up to 2k with switches disconnected, NG does it less pronounced, probably because of my adjustment problems.

In any case - ISV could be tested by removing it and simply applying voltage to it from battery and it should move sharply. If it does not, it could be taken apart and cleaned and greased, but it's very precise work. If you still want to find another one - it's the same on 3A/6A/9A/ACE/NG/NF/AAR and also 2.8/2.9 12v VW VR6 engines.

P.S. If you remove it and try to blow air through it - yes, it's normal that you can blow a bit air through it.

BIGGYIN · 24-05-12, 05:51 PM

I read somewhere(?),to put 9 volts across the ISV.(12 volts,can damage them)

I had a similar problem,with my ISV.(KV engine)
Every so often,it would stall at lights and junctions.Also,sometimes the idle would hold at 1200.
I soaked and cleaned out the ISV and it made no difference.(Also tried another 2 ISV's.)
I cured it,by renewing the ISV sender and spade connector.
Don't know about an NG?But on the KV it's on the bottom of the hose(near cylinder head.),that goes from the rad to the cylinder head.
Mine now ticks over,spot on 850.

(and it only cost me,about £6 from GSF.)

martinws · 24-05-12, 05:57 PM

I have an ISV for a KV engine and one from a ABY. They are different but they will both do other cars as well. Try all of the above and drop me a PM if you still want one.

msh · 24-05-12, 06:05 PM

You're not going to apply the voltage for longer than a second and there isn't more convenient power source than battery. In case of engines with KE3-jetronic or more sophisticated engine managements, ISVs are operated by PWM, dunno about that simple ISV control module of K-jet engines.
It's a shame that in this case idle control isn't as simple as of K-jet engines, and it's done on purpose - so that when something is broken, it could be felt

For KV-like engines that control module is simply opening more or less ISV according to temperature, while on KE3-jetronic/KE-motronic it's a whole different story...

Temp sender could be tested and maybe contacts cleaned, but otherwise it's not worth to change it outright, unless other driveability problems are experienced, because with faulty temp sender there would be starting and running problems.

msh · 24-05-12, 06:11 PM

Quote:

Originally Posted by martinws

I have an ISV for a KV engine and one from a ABY. They are different but they will both do other cars as well. Try all of the above and drop me a PM if you still want one.

It's not worth to try that KV ISV, I haven't seen ABY ISV but I'm doubting that it would be worth to try that either. ECU is programmed to use one exact ISV. For example, what could be when incorrect ISV is fitted - I once had ISV from SD engine [the same like on B5 1.8T engine, with three contacts] fitted on my 3A engine - I used to apply throttle while braking because unless I did so, engine usually stalled - after that small throttle application ECU kept idle somehow, and also threw out fault code about ISV. When I fitted the correct ISV - no problems.

24-05-12, 05:51 PM	#5
BIGGYIN 4 ring whore! Classic Audi Club Member Join Date: Mar 2009 Location: Merseyside Posts: 7,976	I read somewhere(?),to put 9 volts across the ISV.(12 volts,can damage them) I had a similar problem,with my ISV.(KV engine) Every so often,it would stall at lights and junctions.Also,sometimes the idle would hold at 1200. I soaked and cleaned out the ISV and it made no difference.(Also tried another 2 ISV's.) I cured it,by renewing the ISV sender and spade connector. Don't know about an NG?But on the KV it's on the bottom of the hose(near cylinder head.),that goes from the rad to the cylinder head. Mine now ticks over,spot on 850.(and it only cost me,about £6 from GSF.) __________________ q90 B2 Type 85 - q90 B2 Type 85-PROJECT-ABY 20vt KARL. Injection is nice but I'd rather be blown

24-05-12, 05:17 PM	#2
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	So what's the problem with idle?

24-05-12, 05:33 PM	#4
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	Well, ISV can't cause a stall on NG engine, at least when engine is adjusted correctly, because by default when engine is warm, ECU is using ISV to decrease revs - should be around 850 rpm with ISV connected and around 1k with ISV disconnected I'm currently slowly fighting the fight to get my NG idling properly, might be pot, but ECU isn't supposed to keep the revs up at the first place... And 2k rpm at another traffic light - is your throttle rest point properly adjusted? Maybe idle switch sometimes doesn't work? My former 3A engine kept revs up to 2k with switches disconnected, NG does it less pronounced, probably because of my adjustment problems. In any case - ISV could be tested by removing it and simply applying voltage to it from battery and it should move sharply. If it does not, it could be taken apart and cleaned and greased, but it's very precise work. If you still want to find another one - it's the same on 3A/6A/9A/ACE/NG/NF/AAR and also 2.8/2.9 12v VW VR6 engines. P.S. If you remove it and try to blow air through it - yes, it's normal that you can blow a bit air through it.

24-05-12, 05:57 PM	#6
martinws Grown up member Classic Audi Club Member Join Date: Sep 2009 Location: Johnstone Posts: 723	I have an ISV for a KV engine and one from a ABY. They are different but they will both do other cars as well. Try all of the above and drop me a PM if you still want one.

24-05-12, 06:05 PM	#7
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	You're not going to apply the voltage for longer than a second and there isn't more convenient power source than battery. In case of engines with KE3-jetronic or more sophisticated engine managements, ISVs are operated by PWM, dunno about that simple ISV control module of K-jet engines. It's a shame that in this case idle control isn't as simple as of K-jet engines, and it's done on purpose - so that when something is broken, it could be felt For KV-like engines that control module is simply opening more or less ISV according to temperature, while on KE3-jetronic/KE-motronic it's a whole different story... Temp sender could be tested and maybe contacts cleaned, but otherwise it's not worth to change it outright, unless other driveability problems are experienced, because with faulty temp sender there would be starting and running problems.