FleshThorn

I went back and rechecked some of my recent work and upon checking resistance on VAF Meter ( MAF) I found that E2-Vs gave me 1800-800 Ohms. I could watch the ohms change as I stood there. Yesterday I was getting 380 Ohms. I cleaned the pins on the outside chance that oxidation was affecting my readings, but it appears my VAF Meter is faulty unless someone has something to try. Looks like I will be at the junkyards this week. I had been looking for a different air box anyways as mine is a little busted up. I have found a rebuilt VAF Meter for $125 from the autopartsshop.com if my junkyard search doesn't turn one up.

n16ht5

Theres a wrecking yard by me that has some 4runner AFMs, I could probably get one for $40-50 and ship it to you?

FleshThorn

Thanks. Let me check local first. I may get back at you.

FleshThorn

I just had a nice phone conversation with Bob White of Fuel Injector Corp. They test and rebuild fuel injector components to include AFMs and ECUs. If you are in the SF/ Bay area they may be able to hook you up. They can test a #22250-35050 for $25. According to him, Ohm readings to see if an AFM is working can be "iffy". He suggested I test my engine vacuum pressure before I do anything. Seems to me a guy who has been in business for 40 years may know what he is talking about. The truck is running pretty good even with Codes 25, 26 triggering the CEL every 20-50 miles, so I am going to be patient. AFMs for 22REs are proving to be rare items in junk yards around here and I would hate to spend too much cash and find I have a bigger problem.

FleshThorn

I found another AFM today for free. When I checked the resistance between terminals I got about the same, all in spec except for E2-Vs: between 550-900 Ohms. I did notice that manipulating the flapper and then checking R, I would get different readings on E2-Vs. The vehicle that this AFM came off of "ran very well" I was told. Just maybe this one reading being out of spec isn't what is causing my Code 25 and 26. I will check vacuum pressure sometime this week.

FleshThorn

I finally found a AFM that checks out good for $25 off of a 93 hilux. After test driving for a while the CEL came back on with a Code 25, 26 and 41 (TPS). A few weeks ago I adjusted my TPS and got the resistance values in spec. I have addressed the AFM and O2 sensor and thought I had taken care of the TPS. It is raining and dark out tonight, so I will recheck the TPS probably tomorrow or this weekend. I have learned that a potentiometer going bad can give good readings one minute and test bad the next, so maybe I have a bad TPS after all. I can understand where a bad TPS could be the cause of the Codes 25 and 26. The truck is running good, but the gas mileage @ 17 MPG tells me something(s) is not where it should be.

FleshThorn

I rechecked the TPS and it tests OK, but I did find that the four wires had been spliced by Bubba.They were twisted together and taped. I soldered them and used heat shrink.

I got around to checking for continuity from the O2 sensor connector to ECU and didn't find any, but I have never had a Code 21. In case anyone was thinking that I may have mistaken a 21 for 41, No. What would be the likelihood that the lack of an O2 signal would not trip a Code 21 ? I suppose I could unplug the sensor and see if that produces a Code 21. I also tried the voltage feedback test as described in the FSM, but with the digital auto ranging multimeter I couldn't tell anything. If it is the wire it should be easy to run a new shielded one just like I did with the knock sensor.

Edited to add: It takes about 25 miles or so of driving to throw a code. I find it hard to believe that it would take this long to throw a code if there was not an O2 signal getting to the ECU.


Update: I learned today that a lack of an O2 sensor signal does not necessarily produce a Code 21. I remembered finding a loose wire while working on my knock sensor issues. I went back and checked it and sure enough it was the wire running from my O2 sensor and it had been bubba-upped. I know you shouldn't splice a shielded wire much less an O2 sensor wire, but I figured I would give it a try. I should know some time over the next couple of days if the O2 sensor circuit is going to function with my splice work.

FleshThorn

45-50 miles of test driving today and I think I am finally Code Free. I may have to celebrate tonight. I will eventually get around to picking out the connector pins and running new wire straight from connector to ECU pins and get rid of the splices. I hope this thread is finished.