1fz-fe airflow meter tuning (1 Viewer)

[extremesitting]

Hello everyone!

I've been struggling for well over a year to get my 93 80 series to run. I'll save the drawn out process I had to eventually arrive at the point I'm at now, but in short the following items ended up being problems and required attention:

• TPS
• IAC
• VAF
• EGR (eventually deleted)
• O2 sensors
• PAIR valve (eventually deleted)
• Vacuum leaks under the intake plenum
• Injector, TPS, and VAF plugs
• Fuel pressure regulator
• spark plugs
• Fuel pump relay
• Fuel pump
• Fuel filter

Which leads me to the current state. I have a rebuilt VAF that "works". It tests fine and I'm able to get the truck to idle smoothly and rev high. However, to get there I had to dig in to the VAF quite a bit and compare it to a faulty OEM. I found that the clock spring that runs the flapper, and potentiometer was quite a bit more tight than it should probably be. That was leading to the engine failing to fully move the flapper. Not enough vacuum. I backed off the spring and got full range of motion with vacuum. Then I discovered that there was adjustment available in the armature itself which significantly helped the idle.

I finally have this thing running, but all this VAF tuning has me concerned that I could be following a procedure to set them up correctly. All my tuning has been by ear. I know there's a procedure to adjust/tune the VAF bypass though it didn't seem to do much, if anything, for me. Does anyone have any information on these meters beyond the generic install/testing process?

Ultimately I'd like to remove and replace the VAF with a MAF, but the conversion modules for that seem to be rare and information isn't that great for my year.

Thank you for your attention. I feel like I'm pretty far offroad with this project!

 

[Rifleman]

I if want want your VAF meter fixed correctly, contact Air Flow Meter Service - http://bavrest.com/air-flow-meter-service.html They know what they are doing when it comes to repairing these meters,

 

[extremesitting]

@Rifleman Thank you so much for your reply. I do have that spare VAF I could send off. Have you used that service before? If so, how much was the rebuild?

 

[Rifleman]

I have not had the need for their services yet, thank God, But i have read other threads here on mud that report that they do good work, As to their cost to rehab a VAF meter, their web site lists a cost of $365 dollars

 

[TheGrrrrr]

@Rifleman Thank you so much for your reply. I do have that spare VAF I could send off. Have you used that service before? If so, how much was the rebuild?

They did two for me earlier this year and they both work well. Expensive but our option in 93/94 VAF land are limited.

 

[extremesitting]

They did two for me earlier this year and they both work well. Expensive but our option in 93/94 VAF land are limited.

I've got my spare VAF packaged up to send off. In the meantime I have the frankensteined VAF in the truck and it's running ok. I'd need a wideband O2 sensor in the exhaust to get the tune better than it is right now and going that route would cost about as much as getting the spare rebuilt correctly. It idles really well, but it's not a happy camper before it's warm. FWIW the ECT checks out fine.

Did you have to tune the air bypass screw in the VAF after installing the rebuilt units? I'm hoping that's pretty close but it is designed for fine adjustment of AFM as needed.

 

[TheGrrrrr]

I've got my spare VAF packaged up to send off. In the meantime I have the frankensteined VAF in the truck and it's running ok. I'd need a wideband O2 sensor in the exhaust to get the tune better than it is right now and going that route would cost about as much as getting the spare rebuilt correctly. It idles really well, but it's not a happy camper before it's warm. FWIW the ECT checks out fine.

Did you have to tune the air bypass screw in the VAF after installing the rebuilt units? I'm hoping that's pretty close but it is designed for fine adjustment of AFM as needed.

I just installed it and rolled. Truck runs great. I wouldn't even know what screw to adjust.

 

[FMC80]

I used BavRest as well. Nothing but goodness.

 

[voorland80]

what obd1 codes do you have at this point

 

[TheGrrrrr]

what obd1 codes do you have at this point

I don't want to jinx it, but it rhymes with Nun.

 

[extremesitting]

I don't recall any lights since installing the new rebuilt one, but also it wont stay running long enough to even warm up. Updates to the saga are here.

 

[Malleus]

If you have replaced all those parts with new OEM Toyota and it still won't run, I think you can only have one of two problems: the engine harness or the ECM. or maybe both.