question about A/F ratio

[motor602]

on decel, should i be running rich or lean, cuz my VEC1 shows full lean on decel under 3K. the reason im really concerned is that my car is running erratically warm, temp spikes above the third hash, usually under acceleration. Im concerned my VEC1 may not be tuned correctly and the improper fuel delivery may be making my engine run hot.

 

[Qualitywires.com]

On decel you should be running a little rich...I would say if you are running lean that will cause you to run a little hot.

On Decel I have my computer tuned around 12.5-13.5 to 1. It's enough to give me the snap! krackle! pop! and also keep my car a little cool. Don't go too rich...you will foul plugs and also may cause wash down.

 

[Ulysses]

Deceleration is a closed loop state. The PCM should be trying to meter fuel during this state. I wouldn't think you would run full lean unless it was a hard deceleration. In this case, the PCM may shut off the injectors.

 

[KenH]

If you mean your getting completely off the throttle as when you get the crackle and burble sound from the exhaust, raw unburnt gas can hit the O2 sensor momentarily and it will register as a very lean condition (even though it is actually a very rich condition). If that is the case, it is nothing to worry about.

 

[motor602]

thanks guys, and ken thats what im talking about, but i cant honestly say that i remember any of the snap crackle or pop, what im gonna do is tune my VEC back to 0/0 and see if anything changes with the temp. I have taken the car to the tech twice and they keep saying there is nothing wrong with the car the engine is running normally. I really dont believe them though, sneaking suspicions with the water pump for one, but perhaps my VEC isnt tuned correctly.

 

[Qualitywires.com]

Water pump would be a good place to start...You can run some high a/f ratios' and be in vacum and still be okay...but it could be very well that you are getting poor circulation in your coolant which would also effect your a/f ratio numbers..check that thermostat also