i have an 84 camaro with a 283. it has 041 heads, .427 .454 lift cam, alum intake off an 87 305 and electronic q-jet and soon to have headers. the m/c selenoid isn't working so right now its running real rich and using a TON of gas(like a mile a gallon). i can't figure out why the m/c selenoid isn't working, i don't think the selenoid is bad because i plugged another one that was working on another car in while it was running and it didn't do anything. most of the wirning is hooken up exept for the knock sensor and smog stuff. i think the o2 sensor is bad, would that cause it to not work? is there soposed to be a power cable or something near the battery for the ecm to work? what is nessisary for the mc selenoid to work as far as the wiring is concerned?

if i can't get the m/c selenoid to work soon i'm going to get a new carb and intake for xmas. i don't know if i should stay with the spreadbore intake and get a non electronic q-jet and vacume advance dist or an edelbrock performer intake and 600cfm edelbrock performer carb. what will be the performance and fuel economy difference beween the two combos? will the tranny kickdown cable and all work on the edelbrock? thx.

 

What are the duration specs on that camshaft?

Because of the short stroke, the 283 is quite sensitive to duration on the intake and you may not be running clean enough for the 02 sensor to do it's thing.

 

i think the 02 sensor is not working as in broken, would that have anything to do with the m/c selenoid not working? i'm not sure what the duration is on that, i'l look for it, i think its pretty close to stock, maybe a little more

 

Yeah, the O2 sensor is very important, the computer looks at the voltage coming from this sensor and adjusts the duty cycle of the pulses going to the mixture control solenoid.

The solenoid is continuously being quickly pulsed on and off, the computer just varies the percentage of 'on' time according to what the O2 sensor is telling it. If the sensor is shot or disconnected the signal to the solenoid will be way outta line.

You should be getting a 'check engine' light and some codes from the box if this is the case.

 

Yes, there's a power wire near the batt, it powers the ECM. There's a fuse in the fusebox labelled ECM, it does NOT power the ECM, rather it powers all the devices that the ECM drives, including the mixture control solenoid.

Every one of the relays & solenoids associated with the ECM, and lots of the sensors too like the throttle position and the MAP sensors, have a pink wire with a black stripe. Those wires are all spliced together, and get their power from the fuse in question. You can check for 12V at any or all of them with the key on; they should all get power if the fuse is good and the wiring is intact.

The ECM's power connector near the battery should plug into a pigtail that hangs off the batt cable. It's a single pin Weatherpack connector.

Look up under the right side of your dash, make sure the computer is there and plugged in. Then replace the Check Engine bulb if it doesn't come on with the key on and the engine off. It's about the only way the ECM has of communicating with you, unless you have some test equipment.

A broken O2 sensor will not keep the mixture control solenoid from working, but it will keep the ECM from being able to make any sense of the world around it and adjust the mixture using the MCS. It should still click many times a second regardless.

 

there is no wire hooked up at the bat for the ecm. what color is the wire? there is an orange one and a ppl one. the ppl one has clips on it like the ones in the body near the battery but it is conected to the 02 sensor right now like the diagram in the book says but it barely reaches. should i just hook the cable up to the battery without worrying about shorting something out or is there a fusable link that should be there?

 

If your car was a V8 car originally, the O2 sensor wire should be on the other side of the car from the battery: batt on pass side, O2 sensor on driver's side.

On a V8 car the power wire to the ECM is orange IIRC. Your batt cable would have a pigtail hanging off the connector where it hooks to the battery, that this wire would plug into.

Like I said though, if your car was originally a 6-cyl car (which it sounds like it might be), I don't have a clue how it was wired.

 

the car was originaly a v8. the person that had it before me put a 350 crate motor in it. it was sold to a dealer and was stolen out of his lot. he found the car in the woods and the engine and trans was taken out along with the battery and all. all of the wires were cut off so i got 2 new harnesses from the junk yard and put them in. now it has battery cables from autozone with just 2 wires coming from the battery on the pos. one going to the started and a smaller one to the alternator. everything hooked up fine exept the power wire. so i'm assuming i should just find a way to conect the orange wire to the battery, right?

 

Ouch about the cut wires and harness. Sounds like a small Holley or Edelbrock non-emissions carb would come in handy right about now.

Concerning your question about the fuel economy difference between the Edelbrock / Quadrajet carb; chances are a healthy late-model Quadrajet would be set to run much leaner at part-throttle and cruise, so your fuel economy would reflect this.

Throttle response would probably be better with a performance oriented 500 or 600 CFM Edelbrock that is calibrated less for emissions and fuel economy, more for performance. It would run slightly stronger at part throttle but you would pay for this at the pump with one or two MPG difference.

By the sounds of things a performance carburetor would be returning much better mileage than what's going on right now.

 

i put new harnesses in it, my main question now is what should i do about the orange wire. i'm pretty sure thats the problem now since everything else is hooked up. i just don't want to put the wire to the battery and short something out or burn something up. btw, thx for all your help, you've been very helpful.