85 LG4 with original feedback setup.

According to the resistance chart in the haynes manual the sensor is reading around 75*. I replaced it with a new one and still the same thing. I have 5 volts at the connector. THe car only acts up when it's up to temp. If I unplug the sensor the car smooths out. I can't find any vacuum leaks, there's no stored codes. No puddling of fuel in the carb and it sprays a good stream with the engine off and the throttle pulled. I'm lost at this point and kinda pissed since I just bought the car. Can anyone help? I tried posting in the carburetor section but no one wants to discuss anything unless it's an aftermarket carb.

 

Nobody has a GM manual that explains why this is happening?

 

When you disconnect the CTS connector the ECM will use a default value in place of the real value. Which is colder then the engine really is. The ECM may also revert to open loop. So in general it will run richer.

As for the 75* reading, was this after the engine sat overnight and was it also the ambient temperature? I wouldn't trust the Haynes chart either.

RBob.

 

It was checked after the car was warmed up. It's obvious the sensor isn't the cause though. So by unhooking the sensor it causes a rich condition in turn makes the car's idle smooth out. One would thing the car isn't getting enough fuel but spraying starting fluid in the carb while it's running doesn't help the idle. Could the mixture control solenoid be bad or would this be more of a symptom of a bad fuel pump? The car doesnt bog when I jump on the gas. I have checked for vacuum leaks over and over and haven't found anything. The choke opens like it should and these problems don't exist when the car is cold, only when warm.

 

If that 75* was in C that is almost correct for a warmed up engine (167* F). Here are some values:

68* F = 3520 ohms
194*F = 241 ohms

IIRC, the Camaro mixture control solenoid (MCS) will click at key-on, engine-off. Easily heard under the hood.

There are a ton of small adjustments on those carbs.

RBob.

 

Yeah it's clicking away with the key on. I'm going to get a dwell meter so I can see what's going on since I don't have access to a scanner. I don't think the carb itself is the problem, I believe it's gotta be something else, just don't know what.