Idle question
 

Unlike most, my car idle fines on first startup but as soon as it gets little warm the idle roughens up. I odn't think there is a vacuum leak.

Any good diagnostic tips? O-2 sensor maybe? Idle controller?

J. Boggs

Model? Year?

Steve

Oops! 86' 560sl.
 

Thanks.

More Info?
 

Mileage? How long has it been happening? Other symptoms? Done anything to try to fix it?

205k miles, great shape, timing chain 0 stretch,

Changed out leaking EHA and all of a sudden it just started idling rough and smells.

Don't really want to change out the fuel distributor is there is some other explanation. Seems odd that it would crap out shortly after changing out the EHA.

J. Boggs

Perhaps a dirty throttle body? When was it last cleaned?

Did you replace it with a new EHA? Did it come with two new O-rings? It was leaking before, but you didn't smell the gas?

Does the fuel mixture need to be adjusted with a new EHA?

I'm sorry, I meant...
 

the EHA smelled of gas and leaked, now it doesn't leak but the exhaust smells like rotten eggs.

thanks.

Rotten egg exhaust smell is indicative of a rich fuel mixture. Only thing that I would recommend, since I don't know too much about these things (yet) is to check the wiring, and any gadgets that it goes to from there. There is a post that is fairly new, that talks about the EHA and another device that it works with... it may be of help.

-Larry

PS: also check to make sure you didn't accidentally knock off a vacuum line...I think there is one in that area. (I replaced my leaking EHA last year, and don't quite remember if there was a vacuum line in that area or not at this moment.)

The 'rotten egg' smell is not necesarily a rich fuel indicator, it is the sulpher in poorly refined gasoline partially burning to produce oxides of sulpher, SOx, check ignition components, fuel control componants and correct asap, because sulpher will kill a catalytic converter.

What's you gas mileage like? If bad - check O2 sensor. If good - Run some injector cleaner through - could be caused by a bad spray pattern with your injectors causing the fuel not to vaporize properly. If injector cleaner doesn't work - have your injectors checked.I am assuming that you have checked your distributor cap for cracks, carbon tracking and pitting and rotor and sparkplug wires and plugs first.

Gas mileage is poor. I have used a bottle or two of Techron with no joy. I will check the distributor cap again-that's a good idea.

In laymans terms, how does one determine if an O2 is operative?

Thanks.

to check O2 sensor check threads in this forum within the last 3 weeks - very good detail given using a multimeter to check voltages.

I can easily just copy and paste it from my notes
 

There are two types of O2 sensors commonly used: Zirconia and Titania. Zirconia can be identified as having flutes on the end. Titania has an exposed flat element on its end. Both types can be bench-tested using a propane torch and multimeter.

ZIRCONIA

1. Set voltmeter on two-volt scale.
2. Connect positive to sensor lead; negative to sensor housing.
3. Hold sensor with pliers, heat with propane torch and record voltage. A good sensor must be able to produce 0.8 volt or higher within 60 seconds.
4. Next, remove sensor from heat source while observing voltmeter. Voltage should drop within 3 seconds.
A sensor contaminated with silicon, lead, burnt oil, or antifreeze will not pass this part of the test.
To test the sensor's heater, connect the leads to an ohmmeter. Any ohm reading is okay as long as it's not an open circuit.

TITANIA

1. Connect black and gray sensor leads to an ohmmeter set to roughly midscale (200K).
2. Hold sensor with pliers, heat with propane torch and observe ohmmeter indicator. After a few seconds, the ohmmeter should indicate an ohmic value. This reading will vary with flame temperature.
3. After observing reading, remove sensor from heat. The ohmmeter should register infinity.

Might know it would involve a blowtorch.
 

Seems nothing I do is easy.

Thanks.

J. Boggs