balbowskie

I got a 1993 Honda prelude si with a h23a1 engine. I was wondering because I don't think I have a MAF sensor, is there something else Honda uses that is the equivalent of the MAF sensor that some cars have or am i just overlooking something and I do have one?

q16racer

MAP - manifold absolute pressure.

Just fyi, most vehicle nowadays that use a maf also have a map sensor.

97ludedude

Your car does not have a mass air flow sensor. It uses the map sensor along with the throttle position sensor and intake air temp sensor to tell how much air it is breathing in.

q16racer

Kinda. but good enough lol.

The intake and coolant temp sensors are simply fuel corrections solely based on temp on top of regular base fueling. These are active in both maf and map based systems.

balbowskie

Wow, I thought some cars have both map and maf, but not in my case since now that I do know I am not using any maf. Anyone know if the operating voltage range of the map sensor is?

97ludedude

. . .i thought the ecu uses the air intake temp sensor to tell calculate how dense the air is so it can get enrichen it or lean the mixture. So to calculate air density like a maf does it does require the iat. ect sensor just tells the ecu when it can stop riching up the mixture when the engine reaches operating temp. a maf automatically tells how dense the air is no calculations required by the ecu am i incorrect on this?

q16racer

do some research on speed density and I think you will understand better. Temp sensors are just that, temp sensors. They do not sense any loads, thats what the maf and/or map is for. The throttle sensor is juat another sensor to tell the ecu what the driver is wanting to do.

iat and ect are simply corrections made by the computer based on what temp they are reading. When its cold outside and the motor is.cold it will increase cranking fuel because cold fuel and cold motors are tougher to start and vice versa....hotter climates and engines at operating temp take less fuel to start. as you drive and reach differrent coolant temp windows, the fuel correction amount drops.

Just read on speed density, it will help.

balbowskie

Hugh help! thanks alot!!!! I see how this is working now!! I'm going to see what else I can dig up on speed density.