how do i test my afm?

[Damo Monster]

i have a worry that my afm isnt working os well on my '92 ae101 levin... can anyone tell me if there is a test or something you can do to be sure? there arent any error codes lighting up in my dash...

cheers,
damo

[Monsterbishi]

i have a worry that my afm isnt working os well on my '92 ae101 levin... can anyone tell me if there is a test or something you can do to be sure? there arent any error codes lighting up in my dash...

cheers,
damo

Most AFM's use a 5v variable output to tell the ecu what's going on, you should be able to find what wire it is and measure it with a multimeter.

[Damo Monster]

so, like if its poked, then it wont be putting out the 5v? what will the car do if the afm is gumed up or not working?

cheers,
damo

[Mr Revhead]

what makes you think its faulty?

[Damo Monster]

well, i was thinking it might eb running rich or something cause it tends to stink of gas a bit, and smokes a bit too from what im told (although ive never seen it... mind you thouhg, its pretty hard to see smoke when your driving the car... and it doesnt do it at idle, and it doesnt use oil..) and then someone said to me that my afm could be a bit tired... so i thought id ask...

[Bazda]

or the flap inside could be bent and means it wont idle properly

[Ae92typeX]

Can be hard to test afm's, easiest thing to do is if you know anyone else with one, that appears to be fine, just swap it over for a day or two and see if theres any difference.
If ya dont, then yeah, you will need to find out about testing it with a multimeter- but I guess will need to know what readings for what stages of openness

[aesc]

well, i was thinking it might eb running rich or something cause it tends to stink of gas a bit, and smokes a bit too from what im told (although ive never seen it... mind you thouhg, its pretty hard to see smoke when your driving the car... and it doesnt do it at idle, and it doesnt use oil..) and then someone said to me that my afm could be a bit tired... so i thought id ask...

Having the same probs with my MAP ZE. Seems to run real rich (black smoke) at revs and seems to use quite a lot of fuel. Doesnt burn oil either so could the MAP sensor be at fault? Like Damo asked, can the AFM/MAP be tested? What else could cause these symptoms?

[Damo Monster]

unfortunately i dont know any other levin owners in my neck of the woods... but yeah, if somebody out there has done this, please write in...

alternatively, are they expensive/easy to replace? if cheap enough perhaps i could jsut swap it anyway?

[GEOFF]

I take it your running a silvertop 20v? They tend to smoke a bit under hight revs due to over fueling.. this is done to keep the cylinders cool because of the high compression ratio.

(i think)

[Damo Monster]

so it should be black smoke if its over feuling? and yes it is a 20v silvertop...

[Monsterbishi]

I take it your running a silvertop 20v? They tend to smoke a bit under hight revs due to over fueling.. this is done to keep the cylinders cool because of the high compression ratio.

(i think)

I thought 20v's were designed to be lean burning motors?

[GEOFF]

realy? based on what?

[Lanius]

Check your O2 sensor before anything else. If its stuffed the engine will run rich in "safe / limp mode", which also means you'll be blowing a bit of smoke, and burning more fuel than normal.
Cheap to purchase, easy to fit. Tends to be the source of most generic "smoking but not smoking heavily" problems.

Not likely to be an AFM at fault ... they're fairly simple mechanical devices, just a metal flap that gets sucked open by the air moving through the air filter and into the throttle body. If the flap was jammed or something, I'm fairly sure you wouldn't be idling properly (ie, rough idle).

Check your AFM ... its easy enough to get to in a stock system. Unclip and open the air box containing the air filter, and look inside the top half of the box. You should see a small metal flap there which will open inwards when you press it. Should open easily and smoothly with little to no resistance.

[Damo Monster]

ok, i'll check out the afm...

so how do i test/check/replace the O2 sensor? where is it?

cheers,
damo

[aesc]

I thought that the o2 sensor doesnt effect A/F mixture (or black smoke if rich) during wide open throttle (WOT). its more likely to be something else, like leaking injectors, excessive fuel pump pressure, ruptured fuel pressure regulator diaphragm, faulty PCV valve etc. Correct me if im wrong

[Monsterbishi]

realy? based on what?

It was mentioned to me at a garage a while back, I never asked into anything specific, hmm, lets see what google can teach us...

Edit: Meh - Can't find anything that's in English.. oh well... I always thought it would be weird having a high comp lean burn motor...

[Lanius]

I thought that the o2 sensor doesnt effect A/F mixture (or black smoke if rich) during wide open throttle (WOT). its more likely to be something else, like leaking injectors, excessive fuel pump pressure, ruptured fuel pressure regulator diaphragm, faulty PCV valve etc. Correct me if im wrong

aesc - If the engine runs lean (not enough fuel), it runs bloody hot, damaging internals, and causing the seized engines we all have nightmares about. If the ECU isn't getting a valid signal from the O2 sensor, it increases fuel in the mixture to prevent leaning out, and damaging the internals.

Damo Monster - The O2 sensor is located on the exhaust manifold (you should be able to see it somewhere on the top side of the flange / headers going towards the exhaust down under the front of the engine).

The sensor "reads" the amount of oxygen in the exhaust gas as the gas travels towards the exhaust. If there is too much oxygen (running lean), it tells the ECU, and the ECU increases fuel in the mixture. Vice versa if there isn't enough oxygen in the gas (rich).

If it can't tell either way, then it goes into "limp / safe" mode, thus the rich mixture and more smoke when putting down the gas ...

Not too sure about exact cost or replacement, but it shouldn't cost much to get it done if you're unsure. Mr Revhead should be able to source you a new O2 sensor for a good price.

[aesc]

What im saying is dont expect the problems to disappear just by replacing the o2 sensor, theres more to it than that

This site has some good technical articles on all toyota electrical systems, worth a look
http://www.autoshop101.com

[Lanius]

What im saying is dont expect the problems to disappear just by replacing the o2 sensor, theres more to it than that

Fair enough ... depends on how badly its smoking I guess