Running rich

JimmyDean

Registered User
Lately my car has been running pretty darn rich. When you shut it off and get out you can get a faint gas smell, and my friends are telling me that when I drive off at WOT, there is a little black smoke out the pipes. Engine has 173k miles, new iac, new collar nut, IC tube gaskets. Anything I should look at to check this? Also, is there any way to check if the knock sensor is pulling timing? Im suspecting it is because my motor mounts are fairly shot, and I've heard the vibration can be picked up as knock. Another thing, whenever I turn my car off hot, and try to start it again, it will idle really rough and erratically with vaccuum anywhere from 12-8mm/hg. What should I be looking at?
 
If it's running rich and you can smell gas vapor after shut down I would check the evap system to see if the transducer is opening and closing properly. Do you top off your tank when you fill it up? This can flow over into the evap canister and fill it up with raw fuel over time.

Best fix is to pull the canister off it's mounts turn it upside down, and run the car down the freeway 20 miles at a good speed. This will suck the gas out of the canister.
There's always the basics like O2 and MAF.
Ray
 
Don't worry about the black smoke at WOT they all do that due to the very rich fuel tables. If your knock sensor isn't working you would likely get some 'pinging' at WOT. I think you have a small vacuum leak and it expands enough on a warm motor to cause re-start problems and the low vaccum reading. Last time this happened to me I would get stuck somewhere and had to let the motor cool off before it would re-start. I hate to say it but it looks like you need to re-seal the SC and IC joints. Do you have the proper 'nut wrench' for the SC collar so you can torque it correctly (148 ft.lbs I recall).
 
The rich fuel map is true and pretty possible. Are you running platinum plugs? The vacuum leak is also possible but very rare(obviously it happens). Maybe check your coolant temp. sensor. It would cause it to run rich and the startup problems.

It can be checked with an ohm meter, and is free to do. It would also cause your temp to rise higher on the gauge before it starts cooling. There are two temp sensors, one has one wire the other has 2. The single wire is for your gauge, and the double is for the computer, to control fuel map, and fan control.
 

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one thing that I forgot! Do a good inspection and see if you have an exhaust leak before your O2 sensor. This would give you a fuel smell from under the hood. Also contrary to popular belief there is a vacuum in your exhaust most of the time. If this is before the O2 then it can draw oxygen in and the sensor will react thus richening your fuel mixture.

Just another thing to check before you go buying any parts. If you can't tell I'm real big on testing to the problem, before changing anything.


Ray
 
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