Bosch 2 wire idle valve>high idle

[JelmerS38]

I have a Bosch 2 wire idle valve on my Nissan VG30DET engine but it runs 1100 rpm at idle.
It now runs 1100 rpm, if I switch to valve setting 100% inverted it goes to 3000+rpm.
What setting should I use to have it idle at 800rpm when fully warmed up?

[grom_e30]

a lot of the bosch valves used on bmw's work well at about 100hz, some of the 2 wire valves are spring loaded they are wide open at about 60-70%dc closed at about 30% dc and start opening up again but the other way when you go below 30% dc. its like a fail safe the valve opens on the spring if power is lost to the valve to stop the car stalling.

open the idle valve test mode and observe the slide on the valve as you vary the duty cycle is your best bet. that way you can get an ideal for what duty causes fully open/fully closed i guess.

[tryingbe]

On a fully warmed up engine, do what Marek says, then adjust the idle screw until desire RPM reached.

http://www.autozone.com/repairguides/Ni ... 5280075f7c


Once your warm up base idle is set, then you can adjust your BOSCH idle valve's settings.

Side note, you should enable the "Barometric Correction" to "Initial MAP reading" under General settings, unless you have a good reason not to.

[Marek]

On a fully warmed up engine, use the test mode to work out when the idle valve is shut and use that setting. (It'll be when the rpm is at a minimum.) Now adjust the throttle butterfly and/or idle screw to get your desired idle speed.

You can then enter the idle valve opening settings for all of the lower (warmup) temperatures and the final (hot) setting will be the closed setting as already determined.

Typical settings are fully open 80%; partially open between 80 and 39%; closed 39%; open again below 39%. Yours may be different.

kind regards
Marek

[hybrid]

What happens if you disconnect it?
If the idle stays high, the issue is not with the valve.

[JelmerS38]

Side note, you should enable the "Barometric Correction" to "Initial MAP reading" under General settings, unless you have a good reason not to.

I have a good reason not to: The Netherlands is at sealevel and the higest point I can get with the car is a parking garage.....

See my other topic about the idle problem, it is solved now.

[jsmcortina]

Side note, you should enable the "Barometric Correction" to "Initial MAP reading" under General settings, unless you have a good reason not to.

I have a good reason not to: The Netherlands is at sealevel and the higest point I can get with the car is a parking garage..... .

Similar in England.

However, my advice is different. If a customer needs baro correction I would recommend a dedicated baro sensor. The 'initial value' option can easily cause false readings and give problems.

James