Using Bosch Idle On Ms.....

[madspikes 41 1 Cars]

Has anyone out there set their 205 up on a aftermarket ECU using a bosch 2 wire idle valve? I'm in the process of sorting mine out, the last job before she gets pressed into daily use, and just looking a tips / advice on setting it up.

 

How much does the valve really need to open to get the engine to cold idle as the valve opens a mighty big whole?

 

Currently I'm not going for closed loop idle, I'm just setting it up for cold idle just based on coolant temp.

 

Thanks

 

Mad.

[welshpug 1,655]

The valve doesn't open to help a cold idle, rather closes as the engine warms up, it's default setting is wide open.

 

All it does is get a 12v feed to a heater element so quite simple.

 

My Motronic system uses the same valve and has a remarkably stable idle compared to Jetronic

[Tom Fenton 1,540]

Madspikes I guess you are talking about the MI16 type idle valve not the SAD thing Welshpug is talking about.

 

I have tried to get this working on my car and failed, having said that I have now made up a restrictor with a 5mm hole in it, as like you say the size of the aperture is massive, and this leads to the engine revs oscillating either side of the setpoint rather than settling down.

 

I plan at some point to have another bugger about with it, as currently the pipework for it is just blocked off. However when I will get round to that I don't know.

[petert 585]

Has anyone out there set their 205 up on a aftermarket ECU using a bosch 2 wire idle valve?

 

Yes, any ECU that has a PWM (pulse width modulation) output can drive it. Just play with the duty cycle until you get the desired idle speed. 40ms worked fine for me. The option might be called a BAC Valve.

[madspikes 41 1 Cars]

Yes, I am talking about the 2 wirw PWM type.

[Mad Professor 7]

The Bosch 2Wire PWM idle valve runs at 100Hz.

 

I can't renamber the open and close duty cycles, but from memory it's 30%dc and 90%dc.

 

I don't have a spare 2wire pwm idle valve other wise I would confirm that for you.

 

as for the MS2EXTRA PID settings for close loop you will have to play with it, as no two engines I have worked on likes the same settings.

Edited September 1, 2009 by Mad Professor

[madspikes 41 1 Cars]

I have mechanically but not electricaly connected the idle valve, so by default its slightly open (15 - 20% open). The issue is that when the engine is warm idle is around 1700rpm with the idle screw all the way in and the throttle stop wound in.

 

I know when its electrically connected it will close the with a duty cycle of 40%, but do I really want the valve to running all the time like this, once the engine is warm?

 

Whats the norm operating procedure with these valves?

 

Mad.

[petert 585]

Whats the norm operating procedure with these valves?

 

0V - partially open

5V - fully closed

12V - fully open

 

By making a circuit that turns off when cold, then applies 5V when warm, you can control the idle speed successfully with the idle screw. Supplying 0V just ramps up the rpm a few hundred rpm when cold.

[madspikes 41 1 Cars]

I thought these valve were PWM valves, and thus needed a oscillating signal to control them.

[Mad Professor 7]

They are indeed PWM valves.

 

If you have a supply voltage of 12volts, and have a dutycycle of say 50% then you connect a volt meter you would see around 6volts.

 

But each of the valve like to run at a set feq and in this case 100Hz.

 

I have not tried any of the 2wire pwm valve with a clean dc voltage to see how they react.

Edited September 4, 2009 by Mad Professor

[madspikes 41 1 Cars]

I have had some success with the idle valve today.

 

I've set the valve up with a 100hz, cold idle duty cycle of 70 and warm idle of 40. This give a 1300rpm ish idle from cold. Still cant get the warm idle down any further, even though 40 should close the valve...

 

Needs further investigation I think!

 

Mad.

[pugpete1108 62 1 Cars]

well done mate, getting there i'm sure you'll crack it soon

[petert 585]

I have not tried any of the 2wire pwm valve with a clean dc voltage to see how they react.

 

I have. That's why I posted the results.

[madspikes 41 1 Cars]

Sorry for questioning your reply, but I didnt think the valve responded to a DC voltage, but your right they do. As you said the PWM just creates a average voltage for the valve to respond to. I ran some tests using a variable voltage supply and here are my results...

 

Voltage > 8.5 Valve Fully open (0.8A)

Voltage ~= 3.5 Valve Fully Closed (0.5A)

Voltage ~= 5.5 Valve half open / closed (0.75A)

 

The amount the valve opened / closed per input voltage varied depending on if the valve was opening or closing. However this would probabily resolved with vibration from the engine running.

 

So given that a running car battery voltage is 14v,

 

Fully closed = 25%

Fully open => 60%

 

Well in theroy anyway!

 

Mad.

Edited September 13, 2009 by madspikes

[madspikes 41 1 Cars]

The stickness of the valve sees to be causing me a a few issues, so plan to move to closed loop. Has one got any setting for setting up closed loom idle on the MS I.

 

Mad.