I got a 1992 Camaro with the 3.1 motor. It fires right up but the idle is pretty high and the tach bounces around within a 1,000 rpm range. I am going to replace the cap, rotor, plugs, and wires this weekend to see if that helps any. When I'm driving it runs pretty good but again the tach is bouncing around.

I would like to know what base timing is supposed to be set at on these motors? any other suggestions on what could be causing that idle problem would be appreciated.

 

If the tach is jumping around while your driving then it is most likely the ignition coil. If it is just a rough idle do a tuneup and you should be fine.

 

The tach jumps around, in park, neutral, or when driving. The idle also seems kinda high, so I would like to try and bring that down to a normal RPM.

What is the base timing supposed to be on the 3.1 V6?

Any other suggestions would be great.

 

Base timing's 10 degrees advanced, engine warm. (And I guess you know about the EST connector since you asked for base timing- cool!)

 

Hey thanks for the info, and I defenitly know about the EST wire to set the base timing.

Thanks

 

No prob; you might also want to clean out the idle air circuit. On the passenger side of your throttle body, there's an Idle Air Control motor. The pintle of that motor, and the air passageway, get gunked up over time with carbon, and can mess up the idle. Next to the carb cleaner at a parts store, you'll see "air intake and throttle body cleaner for fuel injected engines"- pick up a can of that. (Carb cleaner can harm the fuel injection system; although I don't think it's been proven to hurt it, I say better safe than sorry!)

1. Key off and OUT of the ignition. Don't go near your keys until you're done! (It's easier for me to type it up this way.)

2. Unhook IAC motor's harness. Remove IAC motor from throttle body.

3. Hold motor so the pintle (pointy end at shaft) faces DOWN.

4. Spray ONLY the pintle with the cleaner. Do NOT let the cleaner run into the motor itself! Let the spring stay carbon'd up, you ONLY want to spray the pintle down. If the carbon is stuck good, you could rub the pintle with a cotton rag- don't rub too hard b/c you don't want to move the motor shaft at all.

5. Remove the intake hose from the front of the throttle body.

6. With the plastic tube hooked up to the spray can of cleaner, insert the free end of the tube into the hole where the IAC motor was. Stick the tube in all the way until you get it into the pinhole that the pintle was resting in. (A hole in a hole.) Spray the cleaner. Carbon will run out of the front passenger side of the throttle body.

7. (Optional) Insert the spray can's tube into the passenger side of the throttle body, thru the IAC passageway, and spray "upwards" towards the IAC motor. This'll do sort of a backflush of the passageway. Then repeat step 6 (spray from the IAC motor opening "down").

8. By now the pintle's dried on the IAC motor; bolt the IAC motor back onto the throttle body. Don't overtorque the screws; they're steel screws going into aluminum threads and if you overtighten, you can strip the threads!

9. Reconnect the electrical connector

10. Now get your keys.

This is also a good time to clean out the throttle body and intake of carbon...

11. Inlet hose should still be disconnected. Start the motor.

12. Follow the directions on the can to clean the TB and plenum. Remember to spray the can in bursts (spray for 5 seconds, wait about 20 seconds, spray again for 5 seconds, etc) so you don't overheat and melt the catalytic convertor. And of course you may want to warm your engine up first so you're not revving a cold motor.

 

Excellent info and greatly appreciated. I will defenitly try that this weekend, which is the next time I will get to work on the car.

I do have another question maybe you can help me with. The transmission shifts kind of harsh, not smooth from gear to gear. Do these have any kind of adjustment I can make, to help soften up the shift? Also its revs kinda high even with light throttle before it will shift into overdrive. I can't be sure of exact rpms since the tach bounces around. Could this also be adjusted the same way?

 

There is a TV cable... TV = throttle valve. It's primary purpose is to supply the trans with correct fluid pressure depending on the engine load.

As a side-effect of regulating fluid pressure, it also slightly affects your shifting.

So you could adjust it, there's a procedure in ThirdGen.Org's "Tech Central". After you click https://www.thirdgen.org/newdesign/tech/ , go under the Technical Articles section, then under Transmission, and look for the one titled "TV detent cable for 1973 Th-350 blah blah".

That's actually an incorrect title. The TV cable is NOT a detent cable.

TIP: Before you adjust ANYTHING, in that picture of a V6 motor, where "D" slides against the outside of "C", take whiteout and make a mark on "D". Why? Well if your trans is near-dead, and you adjust the TV cable to it's proper setting, your trans may go bezerk. You'll know as soon as you drive the car. By marking the cable, you can put it back to it's original setting- and then you gotta start saving $$ for a trans.

Oh and I usually use a screwdriver to push the "B" tab in.

 

As a side-note on the high idle problem..check for vacuum leaks as well. Those will cause a high idle cause the engine is getting unmetered air. Also leans it out.