WICKED SC4

Mine must be faulty- I can't even find a new one for a reasonable price...

Dougspeed

iTrader: (2)

Did you try pming Aliga to see if he has a used one?

Dx3

iTrader: (13)

A MAF is not something I would buy used. Like everything else, they seem to go out over time.

I am not sure why you guys are having trouble locating one - I bought one at Sewell Lexus for cheap, and then bought another one at Autozone for even less...

Jonny

SCFrogger

i am not planning on spending more than like 75-100 bucks if i decide mine is doomed.

i think there is a chance of cleaning it if yours works randomly like mine, i am planning on experimenting with it over the next couple days, i will take pics and post if i fix or fry it. i found some interesting things on the 7mgte forums.
same kind of Karman vortex maf and somewhat interchangeable.
my electrical engineering degree must be worth something? right? maybe not..

SCFrogger

ok, i managed to clean it of mostly i think, i will post exactly how to do it cause i took alot of pictures.
only thing is i just put it back in my car, and now it idles right, revs alright, and doesnt stall when i put it in gear. i havent driven it around yet so im not 100% sure its fixed but hell, it wouldnt even stay on before.

only thing is, there is a good amount of consistent white smoke coming out my tailpipe. its kind of a humid morning here and it isnt really warm but there is definately a bit of a fuel smell.

am i running rich now? i assume i am but just confirming, there was never any white smoke at all before i touched my maf and thats the only thing ive done.
im gonna go out and reset the ecu and see if it happens again, cause maybe i didnt wait long enough the first time.

what could this white smoke mean guys, i need to clean it better again?

WICKED SC4

My mechanic said if you spray anything in your maf it will burn it. It has a tiny filament inside that is charged. When it gets hot, the air going through it will cool it off and it will try to put more electric current to heat it. The ECU knows how much air is going through it by how cool that wire gets at a certain current going through it. If it gets caked up with grease and dirt, it wont cool off properly, and throw off the ecu, and run erradicly. If you spray a chemical into the wire the wire will burn as it is tiny and delicate. It's best to just replace with a new one like Jonny said. I wouldn't buy a used one.

Side note: My car is in "my" shop this time, and they said the MAF is bad and the Harness might be bad. They have to do one thing at a time and rule each thing out completely. I hope it isnt the harness, I know the Supra harness is like $1K for each one. I find out today what is the deal-It sounds like these cars have a lot of related issues to whatever this is.

SCFrogger

IF FIXED IT, MY CAR IDLES FINE AND PULLS HARD TO REDLINE!!!

ok, let me clarify, alot of our cars (not sure about sc400) do not have a MAF sensor element. this is the major problem. filament sensor maf's are damn near the easiest thing to clean ever, just spray with contact cleaner, let dry.

92-95 sc300 and maybe some sc400 use a Karman Vortex sensor. basically a laser shoots a beam onto a tiny mirror hidden away that reflects off of this foil which is not so hidden away to detect distortions directly related to the amount of air passing by the foil. sounds complicated, really not.

you have to make sure your foil strips(2) and your mirrors(2) are friggin spotless if you want it to work 100% right. i used the good ol trial and error method im gonna post what i did up to help others.

it will be obvious from the pics wether you have a regular maf or a karman afm

SCFrogger

ok so disconnect the plastic part with 3 screws from the maf. it isnot necessary to remove your whole maf if it is still decently clean.

you will need the following parts: contact cleaner, compressed air, your maf, and a flashlight will help.

basicallythere are 2 of the foil strips circled in yellow. you will want to get a drip or two or contact cleaner on that and wipe with something. i used a tiny srewdriver covered in paper towel. DO THIS LIGHTLY DO NOT SCRATCH.

then you will want to drip some more cleaner, not very much, into the 2 holes at the base of the part circled in yellow. kind of shake the maf around a bit lightly. and before it dries/evaporates too much, hold the unit upside down and lightly spray compressed air at an angle into the foil part towards the hole. dont spray directly in the hole as you might break the mirror loose. you should see the contact cleaner rushing back out of that hole you put it through. we want to get as much of it back out as possible.

repeat for the other side.

i then repeated both sides again to make sure it was clean, very carefully.

then i did the part in red pretty much the same way, although this part is more secure. i think its the temp sensor.

once you convinced it looks dry to the eye, think again it is not.
lasers are way more sensitive than you would think.

take a hair dryer and hld it minimum like half a foot away, further the better. dont get it too hot.

now that you think it must be dry, you are wrong again. i treid to put it on at this point and wouldnt idle, do not worry everything is just fine.

let it dry overnight, or for at least half a day, preferable upside down, the way you sprayed air into it

now before you put it on, wipe the foil one last time with something very clean like a brand new paper towel or something. then give it a shot of compressed air(dont shake the can and make the liquid come out).

put it on the car.
and RESET your ECU. leave the neg terminal off for a while, i did 15 minutes.
when i did 30 seconds it did not reset fully.

before i reset my ecu id idled a little high setlled down and ran fine, but there was smoke and a gas smell, obviously running rich from the last time i tried to fire it up and it had to compensate. i let it burn off and reset my ecu
resetting your ecu might save you from this.

after reset, car does not smoke, idles perfectly and i punched it down the street and i felt all that power back that was missing and the reason i touched it in the first place.

take some advice from me, dont over oil your k&n filter, because no matter how much they deny it they are full of **** and their oil will **** your sensors world.

SClean4

I've noticed that my SC sputters/jerks occasionally (rarely), too, rocking violently up and down, where the car seems like it's about to die. It hasn't happened in a while (a month or two) but it happened again briefly a few days ago. It may be happening while the car might not be warmed up all the way yet and/or hasn't been driven in a few days (two or three). I wonder if it has anything to do with being slightly low on gas sometimes (around 1/4 tank). I use premium unleaded always. Or maybe another possibility is the pre-cats (and/or the center cat) could be clogged, etc.

Anyone experienced this or have info? This might be what the original poster is experiencing, too.

Gunnar

Frogger, I'm glad to hear you got that figured out! Hope I was able to help some.

WICKED SC4

My car is STILL in the shop and they cannot figure it out just yet... This is crazy, I thought I was crazy because I couldn't figure it out, now they can't either. What did Lexus do to my car?

over40driv

Some aftermarket perf. company needs to come out with a better repl. MAF for our 92-95 sc400, I here their weak. Anyone know of one?

SCFrogger

yeah Gunnar, thanks for the help, knew it was just a matter of knowing how to clean the thing. works well now, ditched my over oiled K&N for a more free flowing cone filter with minimal oil. glad the maf has decided to cooperate.

now i can move on to my passenger door handle which doesnt open from inside anymore.

wickedsc, i think you need to try another shop and/or go back to lexus and tell them they need to fix what they obviously messed up. if you have the time grab a fluke and start testing whatever you can. i could be wrong but i think its pretty hard to damage your whole harness. i would still check the maf out if i were you, if they say its bad then you cant really loose anything trying to clean it.

good luck

TheMole

iTrader: (13)

If the dealer refuses to help you after you paid so much to replace the starter, try writing to corporate Lexus. Also, see if there are any surveys and leave them a bad review.

lobuxracer

iTrader: (2)

I thought this was common knowledge...reduced filtration and oil migration are both K&N features. I don't run them on anything but carburetors.