Possibly a stupid question about Idle Stabilisation Valves

Post by **veedweeb** » 11 Jan 2007, 17:00

I've cleaned the ISV on my 2.1 DJ engine and it has improved the tickover, but it's still not right...

I called in at a local car spares place and was quoted £250 ish for a new idle control valve!! Yikes.

Is it the same thing?

And are they the same as the ones fitted to other cars? Golfs, for example. There are a lot of Golf ISVs on ebay, and they are a lot less than £250.

Post by **toomanytoys** » 11 Jan 2007, 17:48

clean it again and make sure there are no vac leaks on any of the joints on the mainfolds and vac lines.. even the intake rubbers..
Also make sure the dist cap and rotor are in good nick and free from damp inside..

Post by **andysimpson** » 11 Jan 2007, 17:53

Clean the throttle as well, the engine will then be less dependant on the idle control valve.

Post by **veedweeb** » 11 Jan 2007, 18:55

OK.. I'll give it a try. Carb cleaner's OK isn't it?

The dizzy cap and rotor are new so I know they're OK.

Thanks for the replies

Post by **tonytech** » 11 Jan 2007, 19:00

Have U bypassed the Idle stabilisation valve electronics?
T

Post by **veedweeb** » 11 Jan 2007, 19:33

Bypassed in what way? I unplugged it, but it wouldn't even start then.

Post by **tonytech** » 11 Jan 2007, 19:43

Unplug the 2 cables from the control unit (2" square block on the lefthand side of the engine bay) one is male the other female. Plug them together. Unplug the green wire below the package.

Many ISV problems are caused by this electronic package (most engines will idle quite happily without it)

T

Post by **veedweeb** » 11 Jan 2007, 19:52

Groovy!

I'll give that a try tomorrow. Thanks

Post by **Simon Baxter** » 11 Jan 2007, 20:40

There seems to be some confusion over idle air control valves and electronic idle stabiliser.
What Andy says, clean the throttle body out.
I can supply a OEM idle air control valve for about £150 if needed.
Also note that the 2.1's idle speed isn't controlled by the ECU but by the idle speed controller behind the right hand rear light.
Again though, common problems stem from temperature senders...

Post by **veedweeb** » 12 Jan 2007, 13:59

I managed to get a couple of hours free (Ah, the joys of working from home!)

I cleaned the throttle body, air mass meter, changed the air filter and cleaned the idle stab valve. I also tightened every hose and electrical connection I could find.

It's better, but still not right, so I decided to try disconnecting the Idle Control unit as suggested by Tonytech.

Behind the right hand rear light which I took to be the driver's side (RHD car) there is only the air filter intake thingy. Behind the other side is a largish complicated looking black box with a big connector (almost like a printer connector) - nothing that looked like it could be joined together.

Consulting the Haynes book as a last resort, it suggested that I should be looking in front of the coil. There are a couple of broken tabs there that look like something has been clumsily removed. Nearby, 2 green wires have been plugged together and a green and white wire is hanging loose. With the engine idling, separating the 2 green wires makes it cut out. So, it looks like a previous owner has bypassed the control unit and removed it!

So, how much are the control units then?

Post by **tonytech** » 12 Jan 2007, 15:37

No idea how much the control unit is. But as I stated above most vans will idle happily without it.

Can you describe what is 'not right about tickover'?
too fast ?
too slow?
Lumpy / erratic?

T

Post by **veedweeb** » 12 Jan 2007, 15:57

It'll idle at about 800rpm reasonably well now, after all I did today (there's an improvement in power too - must have been an air/vacuum leak somewhere).

When starting, even when the engine's warm, for a few seconds it hunts anywhere between 0 and 800 rpm. The same happens when revving the engine in neutral. The revs don't drop back to 800 straight away - coming off the accelerator and the revs will drop to almost cutting out, then hunt around until they settle at 800.

It means that when the engine's cold, at can cut out sometimes.

It's not a huge problem, just a bit annoying.

Post by **HarryMann** » 12 Jan 2007, 17:23

I have an idle control unit somewhere, the one that goes behind the RH rear tailight on Sycnro 2.1's anyway, takes some sort of block connector. Will dig it out this weekend and photo it for you... if its what you need you can have it FOC.

Funny, is it correct that some are mounted on the LH engine bay flitch panel and others behind the RH taillight or are these different units? We've had this conversation before here many times and never quite got to the bottom of it..

Post by **veedweeb** » 15 Jan 2007, 10:16

Wow, that'd be great Harry... Thank you

If you wouldn't mind taking a pic of it, I'd really appreciate it. I think it's completely missing from my car, so I don't even know what it looks like!

Post by **HarryMann** » 15 Jan 2007, 10:48

Right let me looksee today... be back this evening with a result hopefully.