Idle control valve



Please can somebody tell me where the idle contol valve is located and how to diagnose its faulty?

Ive got a high tickover of about 1400-1500 rpm and even with the adjustment screw all the way in i can only get it to drop to about 1200-1300rpm :roll:

cheers lads


New Member
My R is exactly the same.....

Winding the idle screw all the way in drops the idle from 1500 to 1300.

I presume therefore that the idle screw is working (i.e. it adjusts the idle!) - so I'm on the hunt for other causes.

I have been trying to fix this for ages.

What does your boost gauge read at idle? Does it show much Vacuum or not?

After prodding and checking all my boost pipes for leaks (didn't find any) and changing my BOV from a single piston Bailey to a dual-piston Forge my Vac at idle went from just under the zero on the gauge to about -0.6 on the standard gauge.

So I presume I solved a leak somewhere - but the idle stayed the same :(

I've checked the MAF connections are clean - but don't have a sensitive enuff multimeter to read in mV to check the output from it.

I'm gonna take my bleed valve out next to make sure that's not leaking.

Does your idle drop at all from a cold start to being warm.... when cold mine idle's at about 1800rpm then drops to 1500 or 1300 (depending on whether I have the idle screw all the way in!). This makes me presume that the auto-choke is switching off - which makes me presume that the engine temp sender to the ECU is functioning.

As always - check for leaks / split hoses and that the famous rubber bungs are in place. Also check the throttle cable is not over adjusted and has some free play when on the idle stop.

My next steps are gonna be:
1. Remove bleed valve and reconnect Boost Solenoid
2. Check throttle adjustment bars front and rear.
3. Check timing
4. Check Engine Temp Sensor resistance
5. Check MAF voltages
6. Dump it in the canal and claim the insurance!!! ;)

I think it's just a process of elimination but it can be long-winded and can end up being a dodgy ECU.

Just change one thing at a time otherwise you'll never know what caused it!

Anyone got any other suggestions?



New Member
yip - that's the point u reach.

I've been trying to eliminate things for AGES now and am frankly fed up with it. :cry:

What Vac reading are you getting at idle?

GeeTee 8)


New Member
It's a long and winding road then I'm afraid!!

Make a list of all the things it could be then start with the cheapest / easiest and work down the list :)

It can be useful to find someone with a normal idling car to swap bits over to eliminate them from time to time too..... damsite cheaper than replacing things as you go...

Maybe we should generate the absolute hit list of things to check to eliminate a high idle.... and how to check them - it's a fookin common problem...

Good Luck.



if your car is reving on to high always worth checking that one of the small rubber blankoffs on the throttlebodies has not came off there should be four.

drawing air is the most comon reason for high reving.


New Member
btw guys to set the base idle speed your supposed to either use consult..or disconnect the throttle position switch.! or as u turn the idle screw the ecu keeps compensating .. cheers


I had high idle problems pretty much from day one about 1300RPM with the screw all the way in. I found no problems with vac hoses, MAF, Timing etc etc. I then changed the distributor cap and rotor and the idle now sits at about 900RPM warm without fail. Not something I would have thought would make a difference. Sometimes i think these cars have a mind of their own.


New Member
my car suffered from high idle till i got my unichip and boost controller so this points the finger at the ignition timing cause mine has been fine ever since the bloke who fitted uni chip says that all pulsars are the same and suffer from this all the time .


New Member
I found three things that got my idle down

1. plenum bolts loose

2. ignition timing over advanced (ok on jap fuel not on ours !)

3. MAF connections dodgy

4. turn ignition off :p

ps I read once that the TPS only comes into play after 1300 rpm
because of the base map requirement for higher rpm fueling so may work may not...



New Member
the throttle switch sits at the N/S of the inlet manifold..theres a connector there...or easier to get at is the connector near to the standard dump valve.. if yr still stuck p.m me...


Mine used to idle 950 when warmed up every time, since advancing the timing its upto 1000 or 1200 rpm's can't really get it down, idle screw right in, MAF good, and ISCV all clean so will disconnect and reconnect TPs when running out of interest, but on mine i d say its down to the timing but it goes best that way so not too bothered with 1100rpm idleing. :lol: 8)


Still waiting on some shims!
You all might want to check one of the most common ones... There are 2 valves either side of the throttle body that should have rubber stoppers over the valves... Sometimes these can blow off...