If someone could identify a BMW part that physically fit, all the other things like spring pressures, resistance levels etc could be measured and compared.
Having an OEM substitute for a critical NLA part like this would be great.
What are others doing when their VAF’s go bad? ‘94 FZJ80 (2 Viewers)
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If someone could identify a BMW part that physically fit, all the other things like spring pressures, resistance levels etc could be measured and compared.
Having an OEM substitute for a critical NLA part like this would be great.
I got doubts.
Trouble is it isnt constant. You have a range when the flap is closed, then a range when its wide open (it often has a circuit for fully open), but everything in between isnt linear. So testing one meter vs another doesn't help a whole lot when you are trying to find one from a different vehicle that is identical. The open and closed positions could be roughly the same, but everything along the switch of the carbon track is different.
You might be both right.
A similar designed part of a similar size engine might have possibilities worth checking out.
A similar designed part of a similar size engine might have possibilities worth checking out.
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I know enough about electronics to be dangerous, but why can't resistance values be measured and compared.
An open circuit at WOT is open, so that's easily compared.
Part throttle resistsnce could be compared or calculated too
If the carbon strip in one had the same resistance as another, and the swept length was the same, then 30⁰ rotation in one may well give the same resistance as 30⁰ rotation in another.
If the resistance along a certain length of carbon strip is known, and is consistent along its length, then two parts should be comparable?
If the carbon strip is not uniform width/area along the swept length, then things get difficult
They may not ultimately be the same, but still measurable/comparable?
An open circuit at WOT is open, so that's easily compared.
Part throttle resistsnce could be compared or calculated too
If the carbon strip in one had the same resistance as another, and the swept length was the same, then 30⁰ rotation in one may well give the same resistance as 30⁰ rotation in another.
If the resistance along a certain length of carbon strip is known, and is consistent along its length, then two parts should be comparable?
If the carbon strip is not uniform width/area along the swept length, then things get difficult
They may not ultimately be the same, but still measurable/comparable?
The board I threw into my VAF was from a '90 Camry. Same part number stamped on top and looked identical to the naked eye - but that doesn't mean much. I will say it's working fine so far. Truck lacks power, drives like trash, and limps along just like it should!
Joking aside, finding a whole plug and play unit might be difficult (especially from an entirely different manufacturer). But if other Toyotas with a VAF carry a close enough equivalent board, then that could at least provide an inexpensive solution to keep the VAF going and the truck on the road while other avenues are considered. It also seems like the innards are almost always the only thing that would need to be replaced; can't imagine much happening mechanically to the housing. It's not complicated to dis- and reassemble.
Joking aside, finding a whole plug and play unit might be difficult (especially from an entirely different manufacturer). But if other Toyotas with a VAF carry a close enough equivalent board, then that could at least provide an inexpensive solution to keep the VAF going and the truck on the road while other avenues are considered. It also seems like the innards are almost always the only thing that would need to be replaced; can't imagine much happening mechanically to the housing. It's not complicated to dis- and reassemble.
We've been down this road before with BMW's, trying to find replacements for flap type air flow meters.
Measure it and you'll see the problem. The trouble is it isn't constant. Even if you hold it in place the value changes. It is that sensitive to movement, plus the problem is the carbon wears, so you can have two identical working sensors and both read differently due to wear. It honestly astounds me how it even works properly because it's both so sensitive, yet at the same time it has such a large operating range.
I should add you can find replacement carbon tracks (replacement PCB) for sale online that all seem to come from china. I haven't heard of anyone actually using one though. Normally you can clean the carbon and adjust the location of the contacts to run on an area of the carbon that hasn't got deep grooves worn in it.
I forgot to say, If you want to view the resistance of the air flow meter when moving anything, you really need an analogue multi meter too. Digital ones just don't refresh quick enough so you get erratic readings.
The other problem with finding a replacement from another vehicle is finding one that is a similar size. The physical size of the air intake / air flap changes, so using a smaller unit on a larger motor is going to mean the sensor is likely running fully open due to the increased airflow required by the engine. You could overcome this somewhat by increasing the spring tension, making the flap harder to open, but I suspect you are going to continually bounce between the intake being a restriction, the spring tension being too great, and the sensor leaning out.
In the BMW world, a company developed a maf conversion with mixed results. The version that just replaced the MAF and was supplied with a new memcal (ecu eprom) worked well. It was basically a replacement with small wiring changes to the loom. The version they sold that allowed a level of tuning was junk. Lots of people had constant problems with the ecu leaning out.
You can see the maf after the pod filter in the pic of my E30 below.
They originally had bosch flap style air flow meters.
I forgot to say, If you want to view the resistance of the air flow meter when moving anything, you really need an analogue multi meter too. Digital ones just don't refresh quick enough so you get erratic readings.
The other problem with finding a replacement from another vehicle is finding one that is a similar size. The physical size of the air intake / air flap changes, so using a smaller unit on a larger motor is going to mean the sensor is likely running fully open due to the increased airflow required by the engine. You could overcome this somewhat by increasing the spring tension, making the flap harder to open, but I suspect you are going to continually bounce between the intake being a restriction, the spring tension being too great, and the sensor leaning out.
In the BMW world, a company developed a maf conversion with mixed results. The version that just replaced the MAF and was supplied with a new memcal (ecu eprom) worked well. It was basically a replacement with small wiring changes to the loom. The version they sold that allowed a level of tuning was junk. Lots of people had constant problems with the ecu leaning out.
You can see the maf after the pod filter in the pic of my E30 below.
They originally had bosch flap style air flow meters.
Toyota ECUs are notoriously difficult to hack around with, so there will probably not be a chip update for these trucks.
Split Second seems to offer a programmable AFM to MAF conversion product. I wonder if anyone has successfully used one on a cruiser yet?
