MSefi.com read only forum (Jan.15,2018)

I am having problems resolving whether or not I have vacumm leak.

My megasquirt reeds constant atmospheric pressure, and I think the map sensor is broken.

I pulled the hose to the MS and sucked on it and there was no change (from 100kpa to 99kpa)

Will the MS stimulater board tell me if the Map sensor is broken. Or Should I assume that it's broken.
Any help ?

I realy can't find a vacumm leak-

Well, the map reading should certainly decrease when you suck on the hose.

Actually the Stim will not help you much with this problem, although IMHO everyone should have one. I would be checking solder joints etc. before assuming a bad sensor.

Ken

In this case, something like a Mity-Vac would be pretty useful; I've used one to check for bad MAP sensors before.

uph,

For under 15¢ at a drug store, you can get a syringe with which you can pull the kPa down to 30 or less. See number 13 here: http://www.megamanual.com/v22manual/mwire.htm#trouble

If this was mine, before discarding the MAP sensor I would make sure that:
- the pins on the MAP sensor are not shorted together by solder or residual flux,
- pin 23 on the 40-pin socket is not shorted by solder or residual flux,
- the MAP sensor calibration has not been changed,
- then I would read the voltage on the 40-pin socket pin #23 while changing the MAP pressure. Lower pressures should give lower voltages.

If those don't work, can you post some pictures of the board?

Lance.