My AFM Problem

SuperXRAY · 01-29-2009, 06:28 PM

Along with the other problems with this car, which there aren't a whole lot unless the clutch is going, it hesitated when cold (less than 80c on temp gauge).

I'm pretty sure this is why:

I tested the AFM following Clark's Garage procedure. My AFM started out at 0.16v and did not rise smoothly, not even all the way through to full open. The biggest problem, and related to the middle of the above picture is when the AFM would go from the first section of resistance to the second section. It would go from 0.16v to 0.13v and then shoot to 0.17 as it crossed the transition line. I would assume this is the low idle or directly off idle air flow. That first section was wore down to the copper strip on the board.

Please excuse my dirty fingernail...been busy with the car all day.

I verified the Intake Temp. Sensor as well. I moved the wiper arm and am soldering a wire from the Vo terminal to the wiper arm, like the updated AFM's. Everything is nice and smooth now.

Putting this on tomorrow and checking the O2 sensor. I may even be able to put the TPS back in the stock position because when I looked at the screws holding the DME together, they had been messed with...leading me to believe it might already have a recent chip in it. That leads me to my next question:

The connections for the O2 sensor have the single wire that is mounted at the connection point and what appears to be the heater connection for the 3-wire O2 sensor. Both connectors are in the same place, right next to each other. Can I just check that for 12v when I turn the key on? Or, did all the cars have the connectors there, but not all cars were setup for heated O2 sensors?

I don't want to connect a heated O2 sensor, which I happen to have a brand new Bosch one, only to blow a circuit somewhere.

HondaDustR · 01-29-2009, 06:35 PM

If 12v comes out of the 2 wire connector, then it can run a heated sensor, which will last twice as long as a non-heated type. If you're using a universal replacement, the two white wires are for the 12v for the heater and there's no polarity.

SuperXRAY · 01-29-2009, 06:42 PM

That's why I asked...the O2 sensor that is there is a single wire. When the car was on the lift for inspection, the O2 sensor looked rather original, but it's hard to differentiate something that could be 13 years or 26 years old. I'll bet it will be a pain to remove and I'm sure it's worn out by now.

Thanks

HondaDustR · 01-29-2009, 06:53 PM

I could be mistaken, but the heated sensor was a california only thing in the early cars. The later ones all had heated sensors. Probably why it's only got the 1 wire part. Probably still can use the heated one, though.

You might be in for a heck of a time getting it out. I've heard one guy here just started the car and heated up the exhaust pipe to temp to make it easier to break it loose. Seems like the best chance of success.

I just beat the crap out of a 22mm wrench to eventually twist the @#% thing out, taking some of the threads with it when I did mine and had to re-tap them. Then they got tapped crooked, and...

some time with a big file and trial and error got the sealing surface lined up with the new thread angle. I highly suggest trying the hot method by running the engine, because the cold way definitely can suck.

SuperXRAY · 01-29-2009, 07:07 PM

Yep, been there done that. I know the exhaust was redone, sure wish they would have used stainless, as the underside of the car is really clean. The doctor who owned the car now works for Duke University, but I believe he bought the car while in school in California, but I'm not really positive on that one...will have to ask the gf since he's related.

Maybe I'll crank up the Acetylene torch and see if it either breaks it loose or cuts it off! Sounds like a plan. Ha!