lefeur

I'm new to the CCC. I've searched the threads and haven't found what I'm looking for. I hooked up a dwell meter to the green connector, put trans in D and measured the dwell. On the 6cyl. scale the dwell stays rock solid at 20 degrees no matter what I do to the IAB. SHould I adjust the mixture screws? If so which way?

Thanks,
JD

DoubleV

Are you sure your dwell meter works? Is your car warmed up ( closed loop ) when your checking your dwell?

lefeur

Dwell meter works. But now that you mentioned it, I wonder if the thermostat is not warm enough for closed loop. I just bought it and, according to the dash temp. guage, it runs about 170 or possibly even 160. Is 180 a better choice?

THanks,
JD

lefeur

Just bought the car, I mean. Not the T-stat.

DoubleV

Some say that 160-170 is too cold for the engine to enter closed loop operation. My car goes into closed loop at about 135 so I don't know what to say about that. IMO, 180 is a better temp for your engine to run at.

Are you sure your MC solenoid is working? Ground the A and B terminals in your ALDL. Turn key to 'run' but don't start the car. Do you hear rhe MC solenoid clicking?

Sparkytfl

I didnt realize this was a couple weeks old when I typed this all out, so I'm still posting it, since theres no "I fixed it guys" update.

These all assume that you have no open or short circuits, bad wiring to your sensors or computer:

Check the resistance of the coolant temp sensor (the one in the water neck with the two wires) to make sure thats good. Normal is from about 450ohm at 160degrees to 185ohm at 210degrees. I'm sure you could probably wire in an additional resistor in parallel to the sensor to trick the computer if you really want that low temp thermostat.

Make sure your oxygen sensor is both still good and heating up enough. Need to keep the rpms up long enough to heat it. If your car has been switched to headers, you sometimes need a heated sensor. You can tap into the wire, measure between that and a ground, check its voltage. I think about 400-800mv is a normal reading.

Check your throttle position sensor. This one isnt as obvious and actually gave me that problem a couple weeks ago. My dwell was also stuck in the twenties. Tap into the bottom two of the three wires connecting to it (sticking thin wire into the plug before you plug it in works), should be about .48v when the car is at idle (resting on the idle screw, not on the high idle cam). Mine was at like 1.5v, the car never switched over into feedback mode, and my throttle kicker was always extended until I fixed this.

five7kid

iTrader: (14)

In open loop, the dwell defaults to 30 degrees. The computer will go to closed loop when the coolant temp is up to 110 degrees and the O2 sensor is warmed up.

Is your SES light working? Is it coming on while the engine is running? If it's coming on, find out what the computer isn't happy about. If it's working and not coming on, the things Sparky suggested you check are working properly.