Hi,
I am running MS-2 on a V3.0 board with 2.892 FW. I am using a bosch 3-wire fast idle valve. I've got a Glen's garage-type circuit driving the valve. The warm- up curve does modulate the valve, but at every duty cycle one side of the valve has way more voltage. The closed side gets 0-2 volts rms, while the open side gets 9-11 volts rms. So, I can modulate the valve from about 85% to 100% open. I think I have traced this to the IDL-1 signal coming out of the MS-II daughter board. The attached image shows the PWM signal on the scope. The zero part of the duty cycle looks okay, but the positive part seems to have a lot of high frequency noise on it that prevents it from pulling all the way up. The inverse of this signal has a good positve part, but a noisy "zero" that never pulls all the way down. Hence the valve bias towards open. Has anyone seen this before? shouldn't the IDL-1 signal be a nice square wave, without the noise? BTW the signal was captured with the engine off. Any help would be greatly appreciated.
FIDLE PWM signal noise
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0). For tuning/troubleshooting questions, please attached a datalog and your MSQ file to your post.
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
FIDLE PWM signal noise
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Matt Cramer
- Super Squirter
- Posts: 2951
- Joined: Sat Jul 03, 2004 11:35 am
Re: FIDLE PWM signal noise
Please post a schematic of the exact IAC output circuit mods you are using.
