What are others doing when their VAF’s go bad? ‘94 FZJ80

[petegangies]

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I had once pondered asking a place like Bavarian if it would be possible to take a new (china) VAF and modify it so it specs EXACTLY like a Denso unit that works. I tried a few of the available 3rd party VAFs in my 94 and none worked - at all. It was utterly terrifying to have my truck hanging in the balance by three unrepairable POS thin film solder connections and a few threads of wire as a rheostat on a .50 cent pcb board.

It would be great if Denso would do another run.

I have a reman Cardone one here, and it's definitely not an original Denso unit thats been refurbed. I haven't pulled off the lid to check the internals. It was apparently done in 2016 to "factory spec".

PEC Australia use a place called Injectronics who do a full rebuild.. the cost is between $900-1000................. :-|

 

[effjay80]

That's interesting that approach been done. I think I have probably close to $1500 in various VAFs "investments" over the years between new duds and refurb costs. But now 2 perfect OEM units in hand just in case!

IMO the VAF is the one true achilles heel of the 93s and 94s.

 

[petegangies]

That's interesting that approach been done. I think I have probably close to $1500 in various VAFs "investments" over the years between new duds and refurb costs. But now 2 perfect OEM units in hand just in case!

IMO the VAF is the one true achilles heel of the 93s and 94s.

Found another place thats a bit cheaper for a complete overhaul.. $825.. I may need to bite the bullet and get at least one of my units done so I know it's 100%, then keep the others as spares. I guess I'll know if any current issues are MAF related as well. It's just a damn lot of money for a MAF :-(

An aftermarket ecu with full tunability would do away with the VAF altogether.. but you're talking a few thousand then + tuning.

 

[Kabanstva]

What exactly goes bad inside the VAF? Is it a wear and tear item? If someone knows it would save people a lot of time and money rather than just throwing $1,000 at a shop that maybe spends an hour in there cleaning or doing god knows what. What are you getting for $825 “overhaul”? @petegangies

 

[petegangies]

What exactly goes bad inside the VAF? Is it a wear and tear item? If someone knows it would save people a lot of time and money rather than just throwing $1,000 at a shop that maybe spends an hour in there cleaning or doing god knows what. What are you getting for $825 “overhaul”? @petegangies

Apparently it's made as new again.. fully recalibrated, housing cleaned etc. I assumed replacing the board and electronic components but I somehow doubt they're able to source these.. so I don't know exactly what they do unfortunately. I'm with you on this one... I'm very curious as that what exactly they do. They provide a 2 year warranty as well.

As for what goes bad.. the resistor strip gets deep grooves from the copper contacts running along it. Also the solder joints themselves can get weak over time. Any of the moving parts sometimes also need adjusting, cleaning and polishing for better contacts. Here's the inside..

 

[White Stripe]

Found another place thats a bit cheaper for a complete overhaul.. $825.. I may need to bite the bullet and get at least one of my units done so I know it's 100%, then keep the others as spares. I guess I'll know if any current issues are MAF related as well. It's just a damn lot of money for a MAF :-(

An aftermarket ecu with full tunability would do away with the VAF altogether.. but you're talking a few thousand then + tuning.

As I mentioned earlier, you can also install a maf with a piggyback module from split second.

 

[effjay80]

Those are NOT normal pads and solder joints (where the connector leads connect to the board). They're called embedded thin film connections which is why they break so easily when you mess with the screws. You can't simply reflow those connectors onto the pad as there's no metal on the board to adhere to, and often recreating those joints changes the resistance of the signal the VAF is providing. It CAN be done with good professional measuring lab gear but not with a hulking 100w solder gun, unless you get lucky.

 

[petegangies]

As I mentioned earlier, you can also install a maf with a piggyback module from split second.

Not available for a 1994 FZJ80

 

[White Stripe]

Not available for a 1994 FZJ80

View attachment 3848648

View attachment 3848647

I don't know why it could not be adapted to work. The two systems of the 3fe and obd1 1fz are very similar. The only thing I can think of is you'd have to tune the maf for the 1fz.

You also have stuff like this:

Pilot VAF to MAF converter with a bluetooth interface – Pilot Engineering Team

max.pilotpowersupply.com

1993 VAF to MAF conversion & Turbo

My aim with this conversion is to better improve the metering of the air volume going into the engine and to stop the tendency for the VAF unit leaning the AFR at high RPM. The reason I want to fix this AFR at high RPM is I plan to install a turbo setup. There are many options out there where...

forum.ih8mud.com

 

[petegangies]

here's a dynamic bench test of the VAF. While the FSM specifies fully open and fully close values... a video I watched said that you can drop signals through the sweep of the metal flap that are observed as zero's. I have no way to confirm whether this is in fact true... but 3 of my units are all showing zero's during the flap sweep. My IAT sensor tests are within range.

 

[petegangies]

here's the video of the dynamic test I was talking about:

 

[akrover]

My approach was to buy a chinese one off of ebay to use while I sent the OEM one off to Bavarian Restorations for a rebuild. I ended up buying a second OEM off of ebay and sent both my original and the ebay OEM ones for rebuild and ran the cheap chinese one while they were gone. Now I have a rebuilt OEM spare to swap in when the rebuilt OEM one I'm running needs rebuilt someday.

Air Flow Meter Service

Bavarian Restoration refurbishes all Bosch Air Flow Meters to meet factory specifications. Let me tell you that this is one of the most important sensors for your engine. After 10 or so years, these...

www.bavrest.com

If you don't mind me asking, what did BV charge for the rebuild?

 

[petegangies]

If you don't mind me asking, what did BV charge for the rebuild?

Cost is $350

 

[Speedytech7]

I got tired of all the 93-94 engine control nonsense that is so legacy it is becoming hard to find. Went the Haltech route, no more VAFM, no more weird O2 sensors that are basically unobtanium or $250 each, no more distributor/ignitor/single coil, no more dumb fuel pump speed controller. It was just getting to be a burden to find all of this weird legacy engine control equip and half of it was made improperly so when you do find something reman or new it doesn't work and you're out some large sum of money that at best would have netted you another few years of inefficient running. Converting to modern tunable engine controls makes it way more efficient and predictable, not to mention way easier to diagnose if something goes haywire.

 

[TheGrrrrr]

I got tired of all the 93-94 engine control nonsense that is so legacy it is becoming hard to find. Went the Haltech route, no more VAFM, no more weird O2 sensors that are basically unobtanium or $250 each, no more distributor/ignitor/single coil, no more dumb fuel pump speed controller. It was just getting to be a burden to find all of this weird legacy engine control equip and half of it was made improperly so when you do find something reman or new it doesn't work and you're out some large sum of money that at best would have netted you another few years of inefficient running. Converting to modern tunable engine controls makes it way more efficient and predictable, not to mention way easier to diagnose if something goes haywire.

So did you have to switch to a manual transmission?

 

[Speedytech7]

So did you have to switch to a manual transmission?

Nope, wired the A442F into the Haltech and setup trans control. Haltech has fully tunable trans control that supports most 4 and 5 speed automatics right out of the box. I setup the A442 as a generic 4 speed and used most of the presets for an A340, tweaked the shift points until it all was to my liking and driving style. It is worth noting that the 93-94 LC uses a separate TCU though so if you wanted you could just replace the ECU and leave the stock TCU and it would still work (it really just needs the inputs from the NE signal, TPS, and VSS to function) but I liked the idea of removing as much of the old stuff as possible while I was already spending the time to rewire nicely.