VAFM rebuild for '93 4runner
#1
VAFM rebuild for '93 4runner
I have more to post here, mainly technical info but if anyone is interested, the Vane Airflow Meter on the old 3vze can be 'rebuilt' easily. I know it's a common part to replace but they cost upwards of $300 for a rebuilt unit because the electrical unit is sealed in the entire chunk of aluminum. With some patience and a few simple tools you can get these things back within spec and operating fine.
When I was trying to 'clean' my VAFM, I accidentally dislodged the electrical connector and the 4runner wouldn't start at all. (that's what you get for not reading the manual first...) Anyway, I ordered a new unit but realized my old one was out of spec anyway when I tested the resistance.
After some tinkering, I got the old one back together and working great and within specs, the 4runner started and ran fine.
All you need besides a wrench and screwdriver is some silicone sealant and maybe some CRC electronic parts cleaner.
I'll get my specifics (resistance range and which terminals to test) when I find them and some photos if anyone is interested in this that doesn't already know how.
When I was trying to 'clean' my VAFM, I accidentally dislodged the electrical connector and the 4runner wouldn't start at all. (that's what you get for not reading the manual first...) Anyway, I ordered a new unit but realized my old one was out of spec anyway when I tested the resistance.
After some tinkering, I got the old one back together and working great and within specs, the 4runner started and ran fine.
All you need besides a wrench and screwdriver is some silicone sealant and maybe some CRC electronic parts cleaner.
I'll get my specifics (resistance range and which terminals to test) when I find them and some photos if anyone is interested in this that doesn't already know how.
#2
What I originally did was make the mistake of unscrewing the two philips screws that secure the electrical connector to the unit and attempt to pull out the unit to spray some cleaner on what I thought was the MAF (I had just pulled the MAF on my '00 Tacoma and thought it was the same, but alas, no...)
What happened was, several of the spring loaded contacts sprung out and they wouldn't go back into place properly (hence, no start). To get the resistance back to within normal range, I simply cleaned the small plastic nub that has the sensor wire inside of it with CRC electronic parts cleaner and VERY carefully with a pipe cleaner. (wouldn't recommend that one but somehow it worked out for me; I didn't have much to lose on this part as I had a new one on it's way...)
As for getting the contacts into place again, the only option was to use a shop knife to cut all the sealant out around the D shaped plastic cover and pull the cover free. I actually tore the entire circuit board down too just for fun, but otherwise, I put the contacts back into place (photo to come soon...) and did some careful cleaning of all the contacts, taking care not to scratch any of the sensitive parts of the circuit board.
I reassembled everything and used some sensor safe silicone sealant to reseal the plastic cover after cleaning all of the old gasket/silicone off. (Also cleaned the entire unit inside and out). After testing resistance and finding it restored to normal, I reinstalled the old unit and the 4runner worked fine. Make sure you get a good seal as there is some pressure pushing up on the plastic cover when the engine starts. (I initially tested the unit without the sealant just to see if it would work and the engine started but then cut out abruptly; the cover had been blown off)
Also, after getting the new unit, the plastic nub and sensor wire were in worse condition than the old one I had cleaned up. (A1 Cardone VAFM replacement)
Hopefully just a simple cleaning of the sensor nub will do the trick but if not it's worth a shot to tear it down and clean everything carefully (for $300 anyway...)
What happened was, several of the spring loaded contacts sprung out and they wouldn't go back into place properly (hence, no start). To get the resistance back to within normal range, I simply cleaned the small plastic nub that has the sensor wire inside of it with CRC electronic parts cleaner and VERY carefully with a pipe cleaner. (wouldn't recommend that one but somehow it worked out for me; I didn't have much to lose on this part as I had a new one on it's way...)
As for getting the contacts into place again, the only option was to use a shop knife to cut all the sealant out around the D shaped plastic cover and pull the cover free. I actually tore the entire circuit board down too just for fun, but otherwise, I put the contacts back into place (photo to come soon...) and did some careful cleaning of all the contacts, taking care not to scratch any of the sensitive parts of the circuit board.
I reassembled everything and used some sensor safe silicone sealant to reseal the plastic cover after cleaning all of the old gasket/silicone off. (Also cleaned the entire unit inside and out). After testing resistance and finding it restored to normal, I reinstalled the old unit and the 4runner worked fine. Make sure you get a good seal as there is some pressure pushing up on the plastic cover when the engine starts. (I initially tested the unit without the sealant just to see if it would work and the engine started but then cut out abruptly; the cover had been blown off)
Also, after getting the new unit, the plastic nub and sensor wire were in worse condition than the old one I had cleaned up. (A1 Cardone VAFM replacement)
Hopefully just a simple cleaning of the sensor nub will do the trick but if not it's worth a shot to tear it down and clean everything carefully (for $300 anyway...)
#3
Registered User
Awesome information!
I was actually online trying to find out where I could buy a remanufactured unit. I found this thread when doing a Bing search for "vafm reman*"
I guess I won't need to be wasting THAT cash!
Thanks so much!
I was actually online trying to find out where I could buy a remanufactured unit. I found this thread when doing a Bing search for "vafm reman*"
I guess I won't need to be wasting THAT cash!
Thanks so much!
#4
for sure, give it a shot; the worst you have to lose is a little bit of your time. If it works, $300 saved. I think the only thing that really 'wears out' or gets dirty is the plastic nubbin that is inside the air chamber, would for sure start there before tearing the cover off. I would bet most that stop working are due to the dirt and whatnot that builds up in there. (unless you're brilliant like me and pulled the 2 screws and yoinked it apart)
#7
hahhaa, I did promise pics, oops.
Not sure what you want to see, here is one I found with the cover removed:
I have more somewhere, need to look on my external drive when I get home.
don't remove the cover! unless you already messed it up like I did... clean out that plastic nubbing with some CRC electric cleaner first I would say would be the best way to try and get it back within spec.
Will check back here, if you have any questions I will be glad to help with what I know from my rebuild debacle.
Not sure what you want to see, here is one I found with the cover removed:
I have more somewhere, need to look on my external drive when I get home.
don't remove the cover! unless you already messed it up like I did... clean out that plastic nubbing with some CRC electric cleaner first I would say would be the best way to try and get it back within spec.
Will check back here, if you have any questions I will be glad to help with what I know from my rebuild debacle.
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#9
this has to be the awesomest thread on YT ever.... lol
the plastic nubbin is inside the VAFM unit, sticks down from the top where all the brains are. It's about an inch long, maybe 1/8" or so diameter? has a small hole in it and a metal piece of wire inside of it.
Next time I got the camera out in the garage I will pull this thing out to try and get some pics... I said that years ago, I know, but maybe within another year I will actually get a pic posted, sorry guys, hahaaa!
the plastic nubbin is inside the VAFM unit, sticks down from the top where all the brains are. It's about an inch long, maybe 1/8" or so diameter? has a small hole in it and a metal piece of wire inside of it.
Next time I got the camera out in the garage I will pull this thing out to try and get some pics... I said that years ago, I know, but maybe within another year I will actually get a pic posted, sorry guys, hahaaa!
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