Map Sensor Signal

[Rob Turbo 3]

What type of signal do map sensors send? Do they work as a variable resistor, i.e. resistance increaces/decreaces as the pressure raises, or is it a pulsed signal that increaces as the pressure does? Also, do map sensors from NA engines only read vac. or can they do pressure also?

 

The reason I ask is because I'm planning a 5th injector setup (either for my 306 8v turbo to run more boost or to turbo my 205 1.6 gti)

 

Thanks,

Rob

[Pugnut 9 1 Cars]

from a random google :

# The MAP sensor directly receives a 5 volt-reference voltage sent to it by the ECM.

# At idle, about 1.0 to 1.5 volts indicates a low-pressure (low voltage) output voltage.

# At wide open throttle (WOT) about 4.5 to 4.8 volts indicates higher pressure (high voltage) output voltage.

 

as with most ecu sensors it works on the range 0-5v which could be simulated with a potentiometer

 

Al

[Tom Fenton 1,542]

Be careful running a 5th injector, it really is old hat technology with the mappable ECU's available these days, running more boost means that if something goes wrong with that 5th injector that you are relying on, you'll go lean on boost, and this means holed pistons very quickly.

[Rob Turbo 3]

I know it's a "bodge" and I know the proper way is to go for mappable management but it's out of my price range and until I pull my finger out and go self employed or get a better paid job then it always will be out of my price range without saving for a while and doing without things! I can't even afford a "proper" 5th injector controller, hence this post!!!

[welshpug 1,657]

IIRC you can fit a 2bar Cosworth map sensor into the ECU (requires soldering in ) then you can run more boost, bigger injectors to match and get it re-mapped, I'm sure a search will sort out more clarification

Edited March 22, 2008 by welshpug

[petert 586]

As said, MAP sensors are merely variable resistors, which create a voltage divider from being fed usually from +5V and GND. Beware however, that Peugeot MAP sensors work in reverse and may not be suitable for use with aftermarket ECU's. I've found GM sensors the cheapest and most adaptable. In addition, they come in three sizes/ranges - 1 Bar (for NA), 2 Bar and 3 Bar.