I recently purchased a 1991 Toyota 4Runner V6 4x4 with 75k miles. I've been attempting to diagnose a problem I'm having (running too rich) and, in doing so, I decided to test the MAF Sensor with the help of my Chilton's manual.

To make a long story short, I removed the screws on the side of the housing that attach the terminal receiver to the housing INSTEAD of just disconnecting the terminal wire (there wasn't a picture in the Chilton's and I got confused... I'm an idiot... etc). When I did, lots of wires sprung forth which I quickly crammed back in and re-attached the screws. Then I unattached it at the CORRECT location and tested with an Ohm-Meter. Everything was within spec.

The next day, the engine stumbled and coughed and almost stalled once while driving. Check Engine light came on and then went off again. I pulled the codes to find 24 and 32 (Air Flow Meter and Air Temperature Sensor). 4 days later, the truck stumbled again... but this time, no code was thrown.

Is there a way I can fix whatever damage I did to the internals of this component? I didn't pull too hard before realizing I was doing the wrong thing. So hopefully... there isn't too much broken.

If not, I've called my local auto parts store. The part is just under $200 and they can get it to me in a couple of days. But, since it's not on the shelf, they can't confirm for me that it is the entire item including the housing and any other sensors that might have been in there with it. I don't need JUST the sensor... I'm sure the sensor is fine. It's the wiring in the housing of the sensor that may have gotten ripped apart.

Also, as best as I can tell, I have a heated wire Mass Air Flow Sensor. That's what the Chilton's leads me to believe anyway. But, I found some information online that leads me to believe I might have a Vane Air Flow Meter (based on the shape of component that I have). Can anyone tell me what I've got and/or how to tell for sure?

Thanks,
Jim

 

Just to help, I'm pretty sure we have the vane air flow meter type, not the mass air flow sensor that they have on the 3.4L.

 

Even the the Chilton's led me to believe otherwise, after learning the difference and looking at mine, I am fairly certain that I do, in fact, have the Vane Air Flow Meter.

Thank you for helping to confirm this.

 

Revjim, I can have that part for you by tomorrow. Give me a call 972-238-4465, it won't be $200 though. You have to buy the whole assembly and that part (22250-65010) is $450.30. Another suggestion I would have is throw that Chilton's manual away. I have seen more men and women come into my shop that have been mislead and it has caused $100s and in one case $1000s of dollars for them. Bring it up on the drive first and see if one of my techs can salvage what you currently have. Couple of hours of labor would still be less than what the whole part cost. Notice my signature at the bottom, if you are in Dallas then you aren't too far from me.

Todd

 

Actually... I'm in Plano... I just put Dallas because more people know where that is.

I wondered about the part. I looked it up on autozone's website and they had two available. One ran $150... and the other was $500 (plus core charge). That's why I was so worried that the part they were selling me was JUST the sensor and not the entire HOUSING. But, since I've now seen a picture of the Heated Wire MAF, I'm pretty sure I have a Vane AFM, in which case it almost has to be the entire thing as the "sensor" is just a lever inside of the housing and a sort of potentiometer, if I understand it correctly.

I'd be happy to have your techs take a look at it, but I really can't afford $450 for the part if I can fix it myself.

The other problem is that I screwed it up last Thursday, had the problems on Friday and drove it Houston that day anyway. I didn't have any more problems with it so I assumed (hoped with all my might) that whatever I "broke" fixed itself when the truck jerked around when it stumbled. It wasn't until Tuesday coming home from work that it did it again. And yesterday that I decided I needed to fix it. And TOMORROW (this is going somewhere I promise) I plan on leaving at about 5am to head for Indiana. I really can't afford to wait to get a part in so, even though I don't want to, I may end up taking our other vehicle. So... to make that LONG story short, I've got to get it fixed today or... not until next Wednesday.

I called O'Reilly (on 15th in Plano) yesterday and they ordered the part from Houston just in case I ended up needing it. I'm hoping it'll be here today (won't find out until 1pm). That way I can look at the part and see if it really is the WHOLE thing and, if I know they have it waiting for me, I'll be more inclined to cut mine open and try to fix it myself.

What does your shop charge for Labor? It might be worth it t just have it done and out of my hands.

 

Shop charges $75phr but it can depend on what they do sometimes. We are open until 7 today if you go time bring it by.

Todd

 

You're not the only idiot to do that, I did the samething to mine (93 ext-cab V6). When I took the two screws out and pulled on the connector it ripped two or three of the wires off of the circut board on the air flow meter. They are just held on by some very thin foil and it tears very easy. I don't know why Toyota even put those screws there as it is obviously not ever suppost to be serviced that way.

Anyway I was able to fix mine and it is working fine. You have to cut through that silicon seal around the top and pry that top plate off. Once that is off you can see what damage you did and very carefully resolder the wires back to the foil or the foil back to the board or the wire to the board. You will see when you get in there. On mine the check eng light came on and stayed on and the truck would idle fine but would not go above 15 or 20 mph. It probably depends on which wires got torn off the board. When resoldering them be carefull not to have solder from one connector bridge over to another connector or it will short-out the two wires. It helps to have a sharp pointed soldering gun and some very thin solder. Good luck!

 

Oh also when you put the top plate back on reseal it with some silicone sealer. You can see mine after the repair in this picture http://community.webshots.com/photo/...92263572fKwNmW

 

Thank you. This is what I imagined the procedure would be for fixing it myself, but it's good to hear someone else say it. I'm going to give it a shot tonight with a spare AFM next to me, just in case.

 

You've been a big help. Thank you.

I've always done EASY work on my vehicles, but, before this truck, I've always had NEW cars and when stuff got even remotely difficult, I just took it into the shop. So, mostly I just need reassurance that I am doing the right thing or that my line of thought is correct.

Of course, doing stupid things like pulling out screws that aren't meant to be removed doesn't really help my confidence level any.

Thanks, again.

 

Hey you are welcome, my friend. Those two screws are the biggest trap I've run into in DIY auto repair work as well. Why would they have even used screws there is beyond me. Maybe they were hoping to sell lots of AFM to us novice mechanics.

Hopefully you will be able to tell which wire went where. On mine it was fairly obvious by matching up the tears in the foil. I resoldered the foil together but I don't know why you couldn't just get rid of the foil altogether and solder the wires directly to the board. Also I was carefull not to heat the board too much with the soldering gun, I don't know if it makes a difference or not.

 

It really upsets me that the screws are there. But, it upsets me even more that the screws are there without any warning on a part that is so, apparently, fragile. If there's a screw on something, someone's BOUND to take them off. So, either make the parts inside more durable, or file the heads off the screws.

My plan of attack on this will be as follows: Buy the part. Try to fix the broken one. If I can fix it bring the part back and by some silicone sealant. If I can't fix it, put the new part on and bring back the old one for a core charge refund. Worst case is I have a new AFM and am out $160.

 

Yep they should have used rivots unstead of screws. Sounds like a good plan. Just remove the whole top of the air box (the correct way this time) and take it inside and sit down at a table with good light and take your time you will be ok. Just watch out for the conductor tracks on the circut board are very close together and one little drop of solder in the wrong spot will short them out. Good luck.

 

hey mt. goat, what part of oklahoma are you from, i'm from tulsa...we need to get together and wheel, Kyle

 

Howdy outdoorfever nice to meet you. I'm in OKC but I have been meaning to go wheeling with the Oklahoma Trail Chasers Club sometime. Have you ever gone with them?

 

Never! Ever! Remove the two screws that connect to the Volume Air Flow Meter. There are soldered parts connected at the other side of the female connector that will rip apart. They can only be soldered back together by someone with great experience. The replacement part costs more than 200 bucks and that’s a huge set back on these older trucks. I and others have come across this problem:
https://www.yotatech.com/forums/f2/9...maf-afm-19324/
This is what is looks like inside:
http://www.automotiveforums.com/vbulletin/t424744.html
Key Phrase: I broke my VAF Volume Air Flow Meter
Key Words: Volume Air Flow Meter Mass Air Flow

 

Thank you for posting this info. Wish I knew how to solder better! Should I take a picture for the forum? May create some good laughs! Need to gain something out of this mess!

 

Lol i did it to but i had my truck running and when i unscrewed it and pulled it out it sparked and was smoking GB ot a used one on ebay and put in now cel light and trowing code 22 24 31 41 wont go over 20 mph a mb d runs super rich and smokes (black) i thinking i might've fried ecm cause run stright to ecm with no relay or fuse need to fix it soon help

 

Any luck on the fix? I did the SAME THING...I replaced mine with one from a salvage vehicle and I'm getting codes 24, 31, and 41. I also developed an idle surge and minor coolant leak in back of the engine after cleaning the throttle body.

A simple cleaning venture wound up costing me $$$...

I know it's an older post but any help would be appreciated!

'90 Pickup 4x4 3vze 229k