I was wondering what the idle RPM's should be on a 3.1. Also, which sensor (and location please) would affect RPMs, and how rich/lean it's running?

The car has check engine light on, and idles around 800 I think. Every now and then though it will jump up to 1000-1200 or drop way down. A few times it has dropped and died setting at red lights. New to firebirds/V6's and very limited experiance working on anything newer than a '66.

Thanks in advance.

 

Pull the codes - all you need is a paperclip and read: https://www.thirdgen.org/service-eng...ht-error-codes

There's a lot of sensors, any one of which can change idle speed, rich/lean, etc.

Knock, TPS, IAC, MAF, MAP, CTS all feed info to the computer that takes that info and changes fuel and timing accordingly.

 

Ahh ok, was trying to avoid the paperclip thing out of fear of frying it all, but looks like I'll have to. Didn't realize there were that many that could affect the rpm and all. Was thinking like 2, maybe 3 lol.

 

You won't fry anything by using the paper clip trick. It's how GM designed the system, well not to use a paper clip per-se, but to short the two terminals to retrieve and erase codes.

 

hahaha honestly....i think they had the paperclip in mind the whole time

 

Possibly. lol

 

Still curious, is the 800RPM at idle about right, or is that off as well? Was busy yesterday, so going to try the paperclip in a little bit to start to figure out the engine code. Quessing since it's a 92 I'll be using 5&6 instead of 6&12. Hope that's right.

Non related question...the sensor or whatever that sends the temp to the actual gauge (not the coolant temp sensor on the top front of the engine) is it on the passenger side of the engine? I see something down there, but it's really hard to get in there without removing a bunch of stuff. Also been trying to figure out a heat problem. I had posted in the cooling section about this and got some responses, but figured I'd bring it up on the V6 side as well. With a new coolant temp sensor, I could not get the fan to come on at all but the temp gauge was working. Unplugged the coolant temp sensor on the top front and fan runs at start up now, but the gauge no longer seems to work.

 

I'm not sure on the V6 cars - the V8 cars idle at about 600 when warm at op temps.

The sender for the coolant gauge is on driver side on a V8 car, again not sure on a V6 car. The V8 cars have a single green wire runs to it, the sender has a standard male 1/4 inch spade terminal on the end, and the green wire has a standard 1/4inch female spade connector.

 

Yeah, in the other thread in the cooling section that's what people said about the temp gauge sender. I just don't see anything like that on the drivers side of the v6 though. The only thing I see that looks like it might be it, is over on the passenger side down below the exhaust manifold, out of easy reach due to the smog crap and other parts in the way above it.

Oh, and when I was messing with it a few minutes ago it was ideling around 1200 RPMs. This was right after start up though, seems like it's more in the 800 range after running a bit.

 

Temp gauge sender is in the front corner of the driver's side head and does NOT have a spade terminal (well, a typical one, anyways)... It's more of a flat disc on a stem with a white plastic connector that slides over it, and it's behind the A/C compressor pointed towards the front corner of the car.

That thing you described on the passenger's side is the knock sensor. That's for spark timing control.

GM spec is that idle speed should be 700 in Drive when hot for the auto and 600 for a manual (with the IAC closed and disconnected for idle speed setting). What you described is normal. Should be around 1200 ECM controlled when cold and about 800 (ECM controlled) when the coolant temp is above 160*.

And the paperclip trick is the same on the 92 as it is on the rest... The 2 terminals in the top right corner. It's the data transmission terminals that change between the 1227302 and the 1227730 for the ALDL.

 

So it is the two on the top right? (5&6) I was going off the thread linked above and wasn't sure what they meant by later cars. To me a "later" is anything with fuel injection/electronic anything.

And thanks, found the temp sending sensor. Guess I knocked off the connector when I was taking off the compressor and all that to get to the water pump to change it. Now gotta see if I can rig it back up, or how to reconnect to get it working again.

 

Actually, the terminals are 5&6 in the ALDL when looking at it on our cars because it's usually mounted upside down... Those 2 terminals are actually A and B. Oh, and to adjust the minimum air rate, you need to disconnect the idle control motor on the throttle body after having A and B in the ALDL connected for 30 seconds with the engine stopped.