Problems with Bosch 2 wire PWM Idle Valve

[g60peru]

First, I'm using MS2 in a PCB v3.0 with the v2.686t6 code with a Bosch 2 wire PWM Idle Valve. I've assembled the PCB according to the instructions for the PWM Idle control and I'm also using a 1N4001 diode across the valve itself. I'm using 240 Hz PWM frequency and it's very smooth (80 Hz was very rough).

I've been bench testing (using the Stimulator and wiring each real sensor / injector / etc. to test it separately) my setup for quite a bit and everything works perfect except for the PWM Idle Valve.

First I've discovered that MS2 puts full voltage when PWM Idle% = 0% and no voltage when PWM Idle% = 100%. One might think it should be the other way around, but it doesn't really matter because you can set up your PWM Idle table any way you want.

This are the characteristics for my PWM Idle Valve (determined by testing):
Fully open: 55 % DC, 0.5 A current
Fully close: 85 % DC, 0.08 A current
@ 100 % DC it's fully closed and there's 0.0 A current

Until there there are no problems. And as you can see in withoutvalve.jpg if I don't plug the real PWM Idle Valve everything works as I want.

The problem is that when I plug the real thing and it starts to open some inputs get screwed up, specially RPM, AFR and TP. You can see this in withvalve.jpg

A bigger problem I just noticed is that MS2 always starts with a PWM Idle% of 0 % (it doesn't matter what I put in "Start Position" under Idle Control). That means full voltage through the PWM Idle circuit until MS2 gets a RPM signal! (my valve has a 3 ohm resistance, @ full voltage it must take just a couple of minutes to burn out). When it does get a signal, it goes to my table configured values right away. If I take the RPM signal off again, this time it stays @ 100 % (no voltage) so it's ok if I "turn off the engine".

How can I solve this? Is the inputs' noise problem maybe just a Stimulator issue and the PWM Idle Valve is not gonna interfere with them in the car?

THANKS!

[g60peru]

First, I'm using MS2 in a PCB v3.0 with the v2.686t6 code with a Bosch 2 wire PWM Idle Valve. I've assembled the PCB according to the instructions for the PWM Idle control and I'm also using a 1N4001 diode across the valve itself. I'm using 240 Hz PWM frequency and it's very smooth (80 Hz was very rough). I've been bench testing (using the Stimulator and wiring each real sensor / injector / etc. to test it separately) my setup for quite a bit and everything works perfect except for the PWM Idle Valve. First I've discovered that MS2 puts full voltage when PWM Idle% = 0% and no voltage when PWM Idle% = 100%. One might think it should be the other way around, but it doesn't really matter because you can set up your PWM Idle table any way you want. This are the characteristics for my PWM Idle Valve (determined by testing): Fully open: 55 % DC, 0.5 A current Fully close: 85 % DC, 0.08 A current @ 100 % DC it's fully closed and there's 0.0 A current Until there there are now problems. And as you can see in withoutvalve.jpg if I don't plug the real PWM Idle Valve everything works as I want. The problem is that when I plug the real thing and it starts to open some inputs get screwed up, specially RPM, AFR and TP. You can see this in withvalve.jpg A bigger problem I just noticed is that MS2 always starts with a PWM Idle% of 0 % (it doesn't matter what I put in "Start Position" under Idle Control). That means full voltage through the PWM Idle circuit until MS2 gets a RPM signal! (my valve has a 3 ohm resistance, @ full voltage it must take just a couple of minutes to burn out). When it does get a signal, it goes to my table configured values right away. If I take the RPM signal off again, this time it stays @ 100 % (no voltage) so it's ok if I "turn off the engine". How can I solve this? Is the inputs' noise problem maybe just a Stimulator issue and the PWM Idle Valve is not gonna interfere with them in the car? THANKS!
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=135421#135421 -------------------- m2f --------------------
Attachments:withvalve.jpgwithoutvalve.jpg

Posted by email.

[g60peru]

First, I'm using MS2 in a PCB v3.0 with the v2.686t6 code with a Bosch 2 wire PWM Idle Valve. I've assembled the PCB according to the instructions for the PWM Idle control and I'm also using a 1N4001 diode across the valve itself. I'm using 240 Hz PWM frequency and it's very smooth (80 Hz was very rough). I've been bench testing (using the Stimulator and wiring each real sensor / injector / etc. to test it separately) my setup for quite a bit and everything works perfect except for the PWM Idle Valve. First I've discovered that MS2 puts full voltage when PWM Idle% = 0% and no voltage when PWM Idle% = 100%. One might think it should be the other way around, but it doesn't really matter because you can set up your PWM Idle table any way you want. This are the characteristics for my PWM Idle Valve (determined by testing): Fully open: 55 % DC, 0.5 A current Fully close: 85 % DC, 0.08 A current @ 100 % DC it's fully closed and there's 0.0 A current Until there there are now problems. And as you can see in withoutvalve.jpg if I don't plug the real PWM Idle Valve everything works as I want. The problem is that when I plug the real thing and it starts to open some inputs get screwed up, specially RPM, AFR and TP. You can see this in withvalve.jpg A bigger problem I just noticed is that MS2 always starts with a PWM Idle% of 0 % (it doesn't matter what I put in "Start Position" under Idle Control). That means full voltage through the PWM Idle circuit until MS2 gets a RPM signal! (my valve has a 3 ohm resistance, @ full voltage it must take just a couple of minutes to burn out). When it does get a signal, it goes to my table configured values right away. If I take the RPM signal off again, this time it stays @ 100 % (no voltage) so it's ok if I "turn off the engine". How can I solve this? Is the inputs' noise problem maybe just a Stimulator issue and the PWM Idle Valve is not gonna interfere with them in the car? THANKS!
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=135421#135421 -------------------- m2f --------------------
Attachments:withvalve.jpgwithoutvalve.jpg

Posted by email.

[g60peru]

First, I'm using MS2 in a PCB v3.0 with the v2.686t6 code with a Bosch 2 wire PWM Idle Valve. I've assembled the PCB according to the instructions for the PWM Idle control and I'm also using a 1N4001 diode across the valve itself. I'm using 240 Hz PWM frequency and it's very smooth (80 Hz was very rough). I've been bench testing (using the Stimulator and wiring each real sensor / injector / etc. to test it separately) my setup for quite a bit and everything works perfect except for the PWM Idle Valve. First I've discovered that MS2 puts full voltage when PWM Idle% = 0% and no voltage when PWM Idle% = 100%. One might think it should be the other way around, but it doesn't really matter because you can set up your PWM Idle table any way you want. This are the characteristics for my PWM Idle Valve (determined by testing): Fully open: 55 % DC, 0.5 A current Fully close: 85 % DC, 0.08 A current @ 100 % DC it's fully closed and there's 0.0 A current Until there there are now problems. And as you can see in withoutvalve.jpg if I don't plug the real PWM Idle Valve everything works as I want. The problem is that when I plug the real thing and it starts to open some inputs get screwed up, specially RPM, AFR and TP. You can see this in withvalve.jpg A bigger problem I just noticed is that MS2 always starts with a PWM Idle% of 0 % (it doesn't matter what I put in "Start Position" under Idle Control). That means full voltage through the PWM Idle circuit until MS2 gets a RPM signal! (my valve has a 3 ohm resistance, @ full voltage it must take just a couple of minutes to burn out). When it does get a signal, it goes to my table configured values right away. If I take the RPM signal off again, this time it stays @ 100 % (no voltage) so it's ok if I "turn off the engine". How can I solve this? Is the inputs' noise problem maybe just a Stimulator issue and the PWM Idle Valve is not gonna interfere with them in the car? THANKS!
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=135421#135421 -------------------- m2f --------------------
Attachments:withvalve.jpgwithoutvalve.jpg

Posted by email.

[g60peru]

First, I'm using MS2 in a PCB v3.0 with the v2.686t6 code with a Bosch 2 wire PWM Idle Valve. I've assembled the PCB according to the instructions for the PWM Idle control and I'm also using a 1N4001 diode across the valve itself. I'm using 240 Hz PWM frequency and it's very smooth (80 Hz was very rough). I've been bench testing (using the Stimulator and wiring each real sensor / injector / etc. to test it separately) my setup for quite a bit and everything works perfect except for the PWM Idle Valve. First I've discovered that MS2 puts full voltage when PWM Idle% = 0% and no voltage when PWM Idle% = 100%. One might think it should be the other way around, but it doesn't really matter because you can set up your PWM Idle table any way you want. This are the characteristics for my PWM Idle Valve (determined by testing): Fully open: 55 % DC, 0.5 A current Fully close: 85 % DC, 0.08 A current @ 100 % DC it's fully closed and there's 0.0 A current Until there there are now problems. And as you can see in withoutvalve.jpg if I don't plug the real PWM Idle Valve everything works as I want. The problem is that when I plug the real thing and it starts to open some inputs get screwed up, specially RPM, AFR and TP. You can see this in withvalve.jpg A bigger problem I just noticed is that MS2 always starts with a PWM Idle% of 0 % (it doesn't matter what I put in "Start Position" under Idle Control). That means full voltage through the PWM Idle circuit until MS2 gets a RPM signal! (my valve has a 3 ohm resistance, @ full voltage it must take just a couple of minutes to burn out). When it does get a signal, it goes to my table configured values right away. If I take the RPM signal off again, this time it stays @ 100 % (no voltage) so it's ok if I "turn off the engine". How can I solve this? Is the inputs' noise problem maybe just a Stimulator issue and the PWM Idle Valve is not gonna interfere with them in the car? THANKS!
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=135421#135421 -------------------- m2f --------------------
Attachments:withvalve.jpgwithoutvalve.jpg

Posted by email.

[g60peru]

First, I'm using MS2 in a PCB v3.0 with the v2.686t6 code with a Bosch 2 wire PWM Idle Valve. I've assembled the PCB according to the instructions for the PWM Idle control and I'm also using a 1N4001 diode across the valve itself. I'm using 240 Hz PWM frequency and it's very smooth (80 Hz was very rough). I've been bench testing (using the Stimulator and wiring each real sensor / injector / etc. to test it separately) my setup for quite a bit and everything works perfect except for the PWM Idle Valve. First I've discovered that MS2 puts full voltage when PWM Idle% = 0% and no voltage when PWM Idle% = 100%. One might think it should be the other way around, but it doesn't really matter because you can set up your PWM Idle table any way you want. This are the characteristics for my PWM Idle Valve (determined by testing): Fully open: 55 % DC, 0.5 A current Fully close: 85 % DC, 0.08 A current @ 100 % DC it's fully closed and there's 0.0 A current Until there there are now problems. And as you can see in withoutvalve.jpg if I don't plug the real PWM Idle Valve everything works as I want. The problem is that when I plug the real thing and it starts to open some inputs get screwed up, specially RPM, AFR and TP. You can see this in withvalve.jpg A bigger problem I just noticed is that MS2 always starts with a PWM Idle% of 0 % (it doesn't matter what I put in "Start Position" under Idle Control). That means full voltage through the PWM Idle circuit until MS2 gets a RPM signal! (my valve has a 3 ohm resistance, @ full voltage it must take just a couple of minutes to burn out). When it does get a signal, it goes to my table configured values right away. If I take the RPM signal off again, this time it stays @ 100 % (no voltage) so it's ok if I "turn off the engine". How can I solve this? Is the inputs' noise problem maybe just a Stimulator issue and the PWM Idle Valve is not gonna interfere with them in the car? THANKS!
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=135421#135421 -------------------- m2f --------------------
Attachments:withvalve.jpgwithoutvalve.jpg

Posted by email.

[davezed]

G'day g60peru
By chance are you "hi side" switching (ie the PWM is via the +12V and not sinking the return line)? If you are you will find that will create a lot of noise on the +12V supply. Few options in this case:
1) Change over to sinking the valve (ie supply the valve with +12V from maybe you Fuel pump) and then sink the return via MS (MS is better suited to low side switching)
2) Beaf up the +12V line to the PWM circuit internal to MS (I assume you are using the prototype area and have configured a power device like either a FET or power transistor). Some people suffer similar issues when driving lo-z injectors and have used spare inputs (I think on pins 3,4,5,6 but check first) to feed in another +12V line.
3) ensure you have a large electrolyic cap across the supply in the prototype area to the +12V if hi side switching, also a small (maybe 0.1uF and/or 0.01uF) across the switched line.
I use a Ford style 2 wire IAC valve on my car (I think it was about 9 ohms?); I hi side switch the +12V supply to it via a FET and found similar things that you have talked about in that 80Hz it is rather "loud" but 160Hz and it is much better in my application. I ran a wire straight from the D37 +12V supply pin to my PWM circuit along with the large (220uF cap etc) and it seems ok.
If you are low side switching then I would suggest you look at your 0V feeds to MS, check this thread out, its a good source for helping out noisy PCB's=> http://www.msefi.com/viewtopic.php?t=19871

Good Luck

Cheers
DaveZZ

[davezed]

G'day g60peru By chance are you "hi side" switching (ie the PWM is via the +12V and not sinking the return line)? If you are you will find that will create a lot of noise on the +12V supply. Few options in this case: 1) Change over to sinking the valve (ie supply the valve with +12V from maybe you Fuel pump) and then sink the return via MS (MS is better suited to low side switching) 2) Beaf up the +12V line to the PWM circuit internal to MS (I assume you are using the prototype area and have configured a power device like either a FET or power transistor). Some people suffer similar issues when driving lo-z injectors and have used spare inputs (I think on pins 3,4,5,6 but check first) to feed in another +12V line. 3) ensure you have a large electrolyic cap across the supply in the prototype area to the +12V if hi side switching, also a small (maybe 0.1uF and/or 0.01uF) across the switched line. I use a Ford style 2 wire IAC valve on my car (I think it was about 9 ohms?); I hi side switch the +12V supply to it via a FET and found similar things that you have talked about in that 80Hz it is rather "loud" but 160Hz and it is much better in my application. I ran a wire straight from the D37 +12V supply pin to my PWM circuit along with the large (220uF cap etc) and it seems ok. If you are low side switching then I would suggest you look at your 0V feeds to MS, check this thread out, its a good source for helping out noisy PCB's=> http://www.msefi.com/viewtopic.php?t=19871 Good Luck Cheers DaveZZ
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=135631#135631 -------------------- m2f --------------------


Posted by email.

[g60peru]

Thanks for the response davezed!

I forgot to say I'm low side switching (i.e. one terminal of the IAC valve goes directly to 12 V (at the pwer source) and the other terminal is connected to the FIdle lead from the MS2).

I use a 12 V 2 A power source directly off the wall. The MS2 is grounded to the power source through the stim.

I'll try other ground configurations and experiment some more. Right now I'm hoping the problem is mainly attributed to my bench testing configuration, and it'll go away when eveything is properly wired in the car, connected to a real battery and using bigger grounds, etc.

Eduardo

[g60peru]

Ok I reconnected by bech testing setup so that MS2 was grounded directly to the power source (instead of through the stim). The same was done with the 12 V power lead to MS2. Now it works perfectly!!!!
Look at the attached "perfect.jpg" log (I have both a real high-impedance injector and the Bosch PWM IAC valve).

I think anyone installing a MS2 (or any electronic equipment in their car for that matter) should read about "Star Grounding" and why it is so important. Here´s a good explanation:
http://www.geofex.com/Article_Folders/s ... oml_vs_DIY
(It's for another application but the concept is the same).

Now the only problem I still have is that MS2 ALWAYS starts up with a PWM Idle% of 0 %. It doesn't matter what I put in "Start Value" in the "Idle Control" dialog box. It looks as if MegaTune wasn't really altering the IACstart variable in MS2 or something???
This happens wether I choose PWM or IAC Stepper warmup.

Eduardo