What can I do to use a MAP sensor on a twin cylinder engine that has uneven vacuum pulses unlike a multi-cylinder engine. A small vacuum tank to maintain and smooth vacuum? A restrictor in the vacuum line like I have to use when I use syncronizing mercury sticks?
I've heard this is a problem with some engines with alotta cam and overlap that don't make much vacuum at idle. They usually avoid the MAP from what I have read. It seems to me that a MAP is a good sensor to use if possible, no?
MAP sensor on two cylinder
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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).
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
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I would make a central tank or pocket like you said, and then get a signal out from there. Id its too noisy, I would thinnk adding a second tank would fliter out lot of pulses.
two lines in, one line between tanks, second tank, line to MAP
===(TANK)---------------------------------------(TANK)------------(map)
two lines in, one line between tanks, second tank, line to MAP
===(TANK)---------------------------------------(TANK)------------(map)
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Mike_Robert
- MegaSquirt Guru
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A small volume vessel, like a cheap, generic, 3/16" clear plastic fuel filter and a variable restrictor will work with applications like this. Small brass needle valves found at aquarium/pet shops work nicely. You need to increase the restirction just to the point of a fairly smooth MAP reading. I prefer to use this approach while experimenting with various MAP lag filter settings. The apps I apply this to are the Mazda rotaries; these have very violent intake tract excursions when running ITBs. Good success has been attained several times using the RC filtering approach detailed above.
-Mike
-Mike