I'm pretty sure I need to replace my mass air flow sensor based on the advice of two mechanics. I see these things prices from $100 at Autozone to $500 OEM. Does anyone have any advice on where to get one (junkyard, rebuilt, new, etc) and how much I should pay to get quality? Thanks.

 

ALWAYS pay to get quality IMO. If you are going to keep the truck for a while & can afford it, go with the OEM unit, IF you can find one, as they are now discontinued by Toyota. Only one I could find available on the web was this one @ $774!!!
https://www.toyotapartsdeal.com/oem/...-NAP&Filter=()

Next best choice is a remanufactured unit like the ones you've been looking at for $100 to $120. They are rebuilt Toyota units and usually come with a 1 year warranty. Some of these are rebuilt by an outfit called Blue Streak, and their rebuild quality is pretty good. That's the "brand" you'll find at O'Reilleys & some others. There is also one from Cardone (Part # 74-20055). Autozone sells these under the "Duralast" brand name with the same part number. Cardone is very good rebuild quality.

Junkyard part - I wouldn't consider it, as you just don't know what you are getting, & most junkyards will not give you any guarantee on an electrical/electronic part. Most yards are going to want $75 to $100 or more for it anyway, so it just a better idea to get the rebuilt with the warranty.

Last thought. Have you thoroughly checked your vacuum system for leaks? A vacuum leak can sometimes look and act like a MAF problem.

 

Might want to find an actual Toyota guy, you don't have a "mass air flow sensor" what you have is a "Vane air flow meter"..

What are your symptoms, what tests from the factory service manual have been done and what where the results of following the trouble shooting flow chart(s).

The VAFM is largely mechanical with a simple circuit board. I have never heard of a mechanical failure in one, the usual (and pretty rare) failure is the resistance track wearing down or someone trying to take it apart (Someone will be along to post a photo of the wrong way to take the cover off, don't unscrew the electrical connector!)..

You can buy the conductive material and " re paint " the tracks online, I know sparkfun or adafruit sell it among other places.

Even if you have no tools or experience testing a VAFM is really simple and good piece of mind.

 

Wow, that OEM price is crazy! I have not check my vacuum system for leaks but will mention that to the mechanic helping me. Thank you.

 

Symptoms have been happening for a year or more, very intermittent. Sometimes just a hard "miss" or "jump around" for a second at like 45 mph and then back to normal. Lately been noticing more of a bog down when taking off from stop or going from 1st to 2nd gear. Actually died on me twice recently when taking off at a stop light, so I became a little concerned. Originally I thought it was electrical but now it seems more fuel related.
Tried new plugs, wires, Chevron Techron fuel system/injection cleaner, tried cleaning the VAFM with the spray you can buy (did not touch or damage it), etc. I could not get it to show any codes using the jumper test. I have not done any specific checks from factory service manual or flow chart.
My mechanic said it was going into a "flood state" which is why he thought it was the VAFM.
Thank you.

 

Sounds more like the throttle position sensor is on the way out.

 

Semantics. Different name, same animal, same function. https://en.wikipedia.org/wiki/Mass_flow_sensor

 

No, they really are not the same animal or have the same function (although, they are trying to achieve similar goals: measuring the amount of air going into the engine).

I am not sure why the Wikipedia article lumped them together, as they are completely different technologies measuring air flow in different ways.

The way to test a Toyota Volume Air Flow Meter is also a different procedure than how you would go about testing a typical Mass Air Flow sensor.

You also cannot spray "Mass Air Flow Cleaner" inside a Toyota Volume Air Flow Meter and expect the cleaning results you would find on a typical Mass Air Flow sensor.

 

An electric motor and a diesel engine serve the same "function." But if you took your vacuum cleaner in to get it fixed, and the guy behind the counter said "you need a new diesel," I hope you'd realize you need to go someplace else.

We name components so that we have some idea what they do. As old87yota points out, a mass air flow sensor uses different technology than does a Volume Air Flow sensor. To convert Volume to mass (to set the mixture), the ecu needs to know the temperature of the air flow. That's why the VAF also has a temperature sensor. (Oddly, Toyota variously calls the same component a Volume Air Flow meter http://personal.utulsa.edu/~nathan-b...33volumeai.pdf (the function) or a Vane Air Flow meter http://www.cygnusx1.net/Media/Supra/...taTech/h21.pdf (the technology). Just call it a VAF and you'll always be right.)

Having said all that, mikegbuff's problem sounds more like an ignition problem to me. A "hard miss" sounds like the spark plug is not firing, or it's firing at the wrong time. First, verify base timing. Then, see if you can trigger a miss at idle by wiggling the plug wires. Ignition misses can be caused by lots of things, but these are the easy places to start.

 

Here is how to test the VAFM: http://personal.utulsa.edu/~nathan-b...33volumeai.pdf

When testing mine, I found some open spots between E2 & Vs while moving the vane so bought a reman VAFM. That one did the same thing so returned it.

 

On the 22re there are wire bundles that can give you issues wth ignition also that run near the hot exhaust side from the distributor (distributor pickup coil, NE signal). The sheath on these become brittle and cause signal corruption, also if routed near the high tension cable you can have issues.

Similar is the wires to the ignitor from the ECU.

 

Appreciate all the previous input. Still struggling with the issue on my truck. I tried a mass air flow sensor (or Vane air flow meter) that works fine from a truck of the previous year model (same part #) and that didn't correct the issue. I've had a couple mechanics look at it and it's a struggle for them because the issue is so intermittent. No vacuum leaks were found. One did replicate the issue and said it's going into a "flood state" and he thought it had to be the air flow sensor. Since that didn't fix it, he suggested it could be the ECU. I'm kinda down to the throttle position sensor or ECU. The throttle position sensor is about $50 from Rock Auto or $100 from the dealer. The ECU (>$1,000) is not available from the dealer any longer but I've found some options - $200 online to ship my off and have it rebuilt, $300-$400 to get a rebuilt one, $150ish from a junk yard. One dealer said they could test the ECU and TPS and determine for sure if they are bad @ $120/hr troubleshooting. I'm hoping the person who let me try the air sensor may let me try their throttle position sensor sometime (same part # for their model). Their ECU is a different part #. Any suggestions on what I should do going forward? Would it be worthwhile to buy a TPS and/or ECU just to see if that fixes the issue or do you think the dealer could truly tell if either of these are going bad, but only giving intermittent issues? Thanks.

 

If it were me I would continue testing things before throwing money at it.

Have you looked at your injectors at all? Cold start injector constantly on, creating your "flood state"?

Injector factory splices? One of them intermittently cutting out at a certain point while running?

Fuel pump dying? Functions properly most of the time but intermittently cuts out?

I'm just throwing ideas out there.