1988 GT with stock 2.8L. I read an earlier post regarding the "air charge temperature" sensor mounted in the air filter container cylinder which goes bad and causes problems. I checked it out and now have two stupid questions:

1) I removed the ACT sensor, cleaned it, and read "2.24" on my el cheapo multimeter set on the "20K" ohms resistance scale. Actual air temperature was around 88 F. Please tell me that "2.24" somehow equates to 2,240 ohms? That would put the ACT resistance reading in the normal range for high 80s F temperature. I'm not accustomed to using a resistance scale labeled "20K".

2) ALSO, when cleaning the air filter container, I noticed there's an approximate one inch diameter, maybe one and a half inch long stubby tube sticking out toward the left front of the container [as seen from the rear of the car]. This stubby tube has a little non-metallic cap clamped on it so that - I suppose - no air from the engine compartment will be sucked into the engine. Why have the little tube there at all? More mysteriously, there's a rubber hose located just behind [actually, more toward the front of the car] the air filter container which was obviously designed to fit on to the stubby tube. Now the hose is just sitting there, the end close to the air filter container loose and not connected. What gives?

Regarding your questions:

1. With your el cheapo meter. When you set it to the "20K" scale, that means that the meter is reading a full scale reading of 20K ohms. So, if you read a 2.24 that would equate to a 2.24 K ohms which is 2,240 ohms. So apparently your sensor is reading correctly.

2. The metal stub on the air cleaner was at one time hooked up to the hose and in turn is connected to a pipe that runs along the front of the engine compartment and then went into the front valve cover as a way to suck in oil fumes from the engine and run them through the air filter back into the intake and burn up. The problem was that the oil fumes clogged the air filter and the engine already had a PCV valve in the rear valve cover to essentially do the same thing. They discontinued the connection to the front valve cover hence the plug for that little stub of pipe. They did not retrofit the air cleaner container, so they had to plug it with a rubber cap to prevent outside, unfiltered air into the intake. You will note that the air cleaner on a Fiero is backwards from most air cleaners. Most have the air on the inside of the round filter go into the intake, On the Fiero it is the outside air that goes into the intake.

"You got a bunch of guys here about to turn blue" - Mission Control in Houston - "Now they're breathing again"

Thanks! I hoped the decimal in 2.24 was at the thousand ohm position, but couldn't understand why the "20K" label if that was the case. Also suspected the cap was original, as you described, but did not know the "why".

quote Originally posted by wolfwolf: Regarding your questions: 1. With your el cheapo meter. When you set it to the "20K" scale, that means that the meter is reading a full scale reading of 20K ohms. So, if you read a 2.24 that would equate to a 2.24 K ohms which is 2,240 ohms. So apparently your sensor is reading correctly. 2. The metal stub on the air cleaner was at one time hooked up to the hose and in turn is connected to a pipe that runs along the front of the engine compartment and then went into the front valve cover as a way to suck in oil fumes from the engine and run them through the air filter back into the intake and burn up. The problem was that the oil fumes clogged the air filter and the engine already had a PCV valve in the rear valve cover to essentially do the same thing. They discontinued the connection to the front valve cover hence the plug for that little stub of pipe. They did not retrofit the air cleaner container, so they had to plug it with a rubber cap to prevent outside, unfiltered air into the intake. You will note that the air cleaner on a Fiero is backwards from most air cleaners. Most have the air on the inside of the round filter go into the intake, On the Fiero it is the outside air that goes into the intake.

Regarding answer 2: So was there a service bulletin for this? I thought that pipe would be required to be connected as a source of filtered air for the PCV system. Maybe I'm thinking about PCV in its infancy before all of the extreme "can't vent anything to the atmosphere" thinking took hold. Don't you need to have an air source going into the crankcase to ventilate it which the PCV valve draws out and back into the intake manifold for combustion? I just had all the connections to the intake air filter off recently and there was a bit of oil around that fitting. Obviously caused by excessive blowby from the crankcase coming through the tube on the firewall. Am I wrong?

quote Originally posted by FieroDan86: Regarding answer 2: So was there a service bulletin for this?

It was part of a recall. So there should be a TSB on the subject.