VR6 idle screw location

[BarberG60 10]

I've been told there is a screw to adjust the idle speed of my 92 Corrado VR6. I can't find it anywhere. I understand its on the throttle body.

 

Need to sort my idle issue out as its permanently idling at 1300 rpm.

 

Thanks

[fla 9]

Check for any air leaks first. Adjusting the screw on a vr is not really recommended.

[fendervg 30]

Unless it's been touched before it won't be the idle screw. The VR should regulate its idle using the various sensor signals to the ECU. As above - check for air leaks.

[robrado974 1]

Have you replaced the sender to the ECU ? . The sender had gone on my car . There was no fast idle on start up . When it was tested it was reading 74 d , all the time , therefore sending the wrong signal . As above check for splits in the hoses .

[seanl82 23]

As above. There isn't an idle screw on the VR as such. It's just the throttle damper which you can wind in or out if required.

[BarberG60 10]

I have changed the blue temp sensor for a new genuine part .Any other sensors I should look at?

 

I have checked for air leaks and can't seen to find any .I've even bought another airbox as the old one has been seriously butchered about .Sounds great though.

[fendervg 30]

The VR6 is managed by the ECU, which takes input signals from at least 6 or more different sensors - some spring to mind:

- Blue temp sensor for coolant temp

- Crankshaft position sensor

- Camshaft position sensor (Hall Sender)

- Signal from Mass Airflow Unit (behind airbox)

- O2 sensor in catalytic converter

- Temp sender in exhaust/catalytic converter

- Throttle position sensor

etc. I'm sure I've missed a few. Did you scan the car for faults?

[Jim Bowen 1]

I've also heard that if it can't get a reading from a sensor it will default to a high idle setting instead.

[BarberG60 10]

Looks like I'll be looking at checking some more sensors then.

I'll leave the idle screw alone, thanks for the advice

[robrado974 1]

If your going to change the temp to ECU sender , which I think could be your problem , you may as well change all four of them . They should come with new 'o' rings and circlips .

[BarberG60 10]

If your going to change the temp to ECU sender , which I think could be your problem , you may as well change all four of them . They should come with new 'o' rings and circlips .

 

Wove fitted a new genuine blue sensor which I thought was the temp to ecu one?

[fendervg 30]

Blue sender is the coolant temperature to ECU signal. Not sure what is meant by four - there are three in the thermostat housing, one for the dash temp gauge and fans, the blue ECU one and a separate radiator fan controller one. Other temp sensors are on the inlet manifold, catalytic converter and on the radiator itself.

[robrado974 1]

Sorry yeah , when I said four , I meant to say three in the block and the rad sender .

[BarberG60 10]

I can't find any air leaks, checked breather hoses etc.

I disconnected the isv and the idle stayed exactely the same, high at around 1300 rpm. Am I right in saying the engine should splitter and die when the isv is disconnected?

[fendervg 30]

Not always in my experience - you should however see a change in engine note and possibly cut out when you disconnect the MAF sensor wiring.

[Kevin Bacon 5]

Sounds like the throttle stop might have been adjusted. You need to plug in VAG-COM really and see what the throttle position is at idle is. Should be around 14 degrees.

[fendervg 30]

Good advice from Kev there - you really need to get VCDS or VAG.COM hooked up to the car, scan for fault codes and take some readings.

[BarberG60 10]

Very sound advice guys, thanks. However, there is no obd port fitted .The car is an early 92 VR6. There are two wires/connectors under the gearstick surround.

I appreciate it is not wise to adjust the throttle stop without checking it, but is there a visual way to see if it has been adjusted in the past incorrectly?

[fendervg 30]

Those two wires allow you to connect an OBDII scanner cable using a 2x2 adapter that is available from Ross-Tech. If you were in Ireland I;d be happy to do it for you!

[robrado974 1]

Yep as above , mine is the same and its been on a vagcom a few times .

[BarberG60 10]

Whilst playing around today, and couple of observations.

When I disconnect the isv, no change in engine speed or tone so cleaned that out with no change.

I disconnected the hose from the rubber intake boot that runs to the isv and the engine obviously stalled. The strange thing is, if I plugged both ends of that breather pipe running from the inlet boot to the isv (with my fingers crudely) the idle speed was perfect.

Any ideas what this would indicate?

[fendervg 30]

Dodgy ISV or faulty wiring to the ISV? Did you essentially bypass the ISV during your test? Get a multimeter and pull the plug off the ISV and check for current and good signal there to rule out the loom, then replace the ISV with a known working one maybe.

[BarberG60 10]

Yes, bypassed the isv and it seems to idle perfectly. I suspect it's the wiring at fault to be honest and that would explain why nothing happens when I disconnectedtut when the engine was running.

[Kevin Bacon 5]

The idle valve could be stuck open mechanically. That would also explain the 1300rpm idle and nothing happening when disconnecting it, although if it was stuck fully open, it would idle at more like 2000rpm!

 

Remove the ISV, make up a little wiring loom for it to connect directly to the battery. If you pulse the positive lead on and off, you should see the flap inside the ISV move and the whole thing will shake in your hand. If nothing happens, it's fooked! And they are, erm, about £250 from VW!!