Mass Air Flow Sensor Not BIke

[Yammer Dan]

The Mass air flow sensor on my work car, (93 Buick Century with 191k) Crapped out. $400. I ain't putting that in it if I don't have to. What do these things do? Unplugged it and it runs better than it did. Check Eng light on but runs geat. Will it hurt anything without it?? What does it do?? Old Buick is great old car uses no oil and runs good. Hate to part with it.

[got2mnytoys]

measures the amount and temperature of the air coming into the engine so that the computer knows how much fuel is needed.

[pegscraper]

Could you get one from a wrecking yard? I couldn't see them wanting that much for one. Check ebay.

[waterbug]

Have you tried pep boys or a discount auto parts place? They might be cheaper, stay away from auto zone on parts like these.

[BradT]

measures the amount and temperature of the air coming into the engine so that the computer knows how much fuel is needed.

 

This is correct but is also used in conjuction with the oxygen sensor so that if your air mixtures changes (altitude changes, cold or warm temps), it can correctly regulate the fuel required for proper burning.

 

The main concern would be your gas mileage. Quick search looks like you can get one new for about 160 bucks. These are pretty common part for GM and is probably used on many different vehicles, so should be easy to find a used one, or about half the price.

 

BRad

[flb_78]

there's some used ones on ebay.

 

here's one the ends in 22 hrs.

 

no bids on it, starts at 9.99 with 10.00 shipping.

 

ebay item number - 180299047406

 

I'd probably just get a used one from a salvage yard if the price is comparable.

[Yammer Dan]

So if my gas milage don't suffer too much just leave it unpluged will cause no harm??

[Yammer Dan]

OK Fib now I'm confused (again) This shows the intake valve? itself. I thought the sensor was the little box on the side of it. When I just unplug the electrical box on the side of the Air Mass Flow valve? It runs fine. Plug it up and won't hardly run at all. Not sure what I need now. Are they trying to sell me this entire unit? Do I need it or just the switch?

[Black Owl]

Dan,

 

You can probably run the car without the mass air flow sensor. I wouldn't recommend it, but you could do it if you don't mind lousy gas mileage, fouled plugs and valves, shortened mileage between oil changes and fouled cat converters....

 

Just my 2 cents here.

 

[CrazyHorse]

Check Rockauto.com here http://rockauto.com/ they have decent prices.

[jlh3rd]

i'm gonna answer your question......when you disconnect the maf...the computer tells itself to run in open mode...this means the computer reverts to a set air/fuel ratio and is not controlled by the computer anymore.....basically it is a fail safe mode...designed to keep the car running....and isn't using the 02 sensor to control fuel mixture....fuel mileage will suffer a little and your converter won't like it....when the check engine light is off, your car is running in closed loop mode where the computer uses sensors to control mixture, timing etc........i would not recommend buying a used maf.....but it's your money......also, 1993 is first generation OBD and not as sensitive as 1996 to present OBD2.......i tried to keep this short, if you need more info , i'll try to answer

[Yammer Dan]

Ran it about 100 miles today. Ran better than it has in long time. Not really getting what is wrong. If you unplug it it runs great. Which means it is opening up to let air in. Is the little black box what is messed up and it is not telling it when to open?

[jlh3rd]

ok, the mass airflow sensor doesn't open or close..that's what your throttle body does....the maf is mounted in front of the throttle body.....the maf does exactly what its name is , it measures the amount of air flowing thru it into the throttle body......the computer uses this measurement, plus other sensors to vary the air/fuel ratio for maximum efficiency, emissions and drivability....you don't have to have the maf connected......you don't have to have the 02 sensor connected...you could probably disconnect all your sensors and the car will still run and, because it's a '93 with first year OBD , it'll probably run fine.........why does it run worse with the maf connected? because it is sending a FALSE signal. that's different than NO signal....the false signal read by the computer means the computer is setting an air/fuel ratio that is incompatible with the driving conditions....so, it could be idling bad, or missing, or hesitating....you disconnect the maf...now it's sending no signal, the computer reverts to a set air/fuel ratio, and the car runs fine.......this is one way to trouble shoot a computer car....if you disconnect the alleged sensor, and the car runs better...then that sensor is probably bad......

 

does this help...........

[jlh3rd]

i should probably ask you what the trouble code number is..............and there could be two codes stored now.....one that says the maf is sending the wrong voltage and/or one that says no voltage, no signal...........you may have to plug the maf back in and read that code

[Dano]

Sounds like he's talking about the throttle position sensor............ Whadya think, Dan????

 

 

JMHO

 

Dan

[jlh3rd]

he might be...that's why it's hard to help people on a computer...... i have to make a lot of assumptions and we know how that word is spelled..........if it is his tps, then the same explanations " basically " apply.........which brings up the price.question.....a tps is normally not that expensive..........a throttle body is......maybe he's pricing throttle bodys.........most tps's are mounted externally to the throttle body, and are replaceble..........

 

so...is it your tps or maf...........

[Yammer Dan]

he might be...that's why it's hard to help people on a computer...... i have to make a lot of assumptions and we know how that word is spelled..........if it is his tps, then the same explanations " basically " apply.........which brings up the price.question.....a tps is normally not that expensive..........a throttle body is......maybe he's pricing throttle bodys.........most tps's are mounted externally to the throttle body, and are replaceble..........

 

so...is it your tps or maf...........

 

 

I think you got it. Thats what I thought til they tried to sell me whole thing. Whole unit is Throttle Body with Mass Air Flow Sensor connected to side of it. One for sale on E-Bay he called it Mass Air Flow Sensor and showed throttle body. You could see wires coming from it but he didn't show side of it where what I thought was sensor was

 

Am I making sense now ?? I'm getting confused..

[flb_78]

Take a picture of the part and post it so we can see it.

[Yammer Dan]

Camera?? Still a dream. I have a Kodak easy share but haven't figured it out yet.

[Redneck]

I would get a can of b12 chem tool and clean it that will often cure the problem.

[93 venture]

picture one is a maf, picture two is a gm throttle body with a tps sensor on the side.

[Yammer Dan]

I think it is the MAF but it runs great without it. I think I only need the sensor and not the entire unit as they are trying to sell me. Drove it all week and it ran great.

[93 venture]

The sensor is the whole unit, like redneck said you can take it off and try to clean it inside,some times they get a little junk on the hot wire and will cause them to mess up,but it sounds like it just needs a new one,with it unplug your fuel system is running blind,the computer has a default seting that will let it run but it has no ideal how to send the right fuel air mix to the engine and will cause it to black your plugs,mess up the 02 sensors and even plug up the converter.It may seem to run ok without it but its not.