1982 380 sl Distributor

[NewmanP]

My Question is this. Can a Distributor go bad. It's in an 82 sl
I just had to replace the coil and cap and router. It's running rough at Idle


Replaced also everything to do with fuel. Fuel distributor, idle control module,
lamba control module. o2 sensor

[meltedpanda]

yes, wobble ( from shaft wear), sticking plate ( from dirt) but lots of other things cause rough idle. have you evaluated your temp sensors?, Throttle plate movement?

[NewmanP]

Hi Ron,

The 02 sensor has been replaced. There is a new air mass controller and it has been adjusted. It Start right up and runs Great Plenty of power on the open road. They only time I feel the idle problem is when I am at a stop light
Just siting there. It idles at 500 rpm's and stays there .

Thanks
Pete

[meltedpanda]

I believe you have a K jet on your SL, but from what you said, check out your AAV for correct function and how long since injectors have been services

here are the most common issues to check, this assumes the temp sensors are all up to snuff


Rough idle (cold)


1)Cold control pressure incorrect;
The movement of the control plunger will be limited if the cold control pressure is too high.This in turn will limit the amount of fuel able to be delivered through the injectors.The result will be a lean ratio and will cause rough idle.

2)Auxillary air valve defective;
If defective and not opening,idle cannot rise and results in rough idle.

3)Airflow sensor adjusted improperly or binding;
If the movement is not smooth,it will result in air-fuel ratio errors.

4)Leaking cold start injector;
If the cold start injector is leaking,the engine will be overfueled even if cold.If the cold start injector is leaking,the idle will get worse as the engine temperature increases.

5)Injectors have an unequal flow or spray pattern;
Do an injector flow test and replace any that do not deliver the correct amount of fuel or have a poor spray pattern.


Runs rough (warm)

1)Warm control pressure incorrect;
Incorrect warm control pressure that is too high or low will cause an incorrect air-fuel ratio,thus resulting in a rough idle.

2)Airflow sensor adjusted improperly or binding;
If the movement is not smooth,it will result in air-fuel ratio errors.Check for centering and correct rest height.

3)Leaking cold start valve;
Again,will result in overfueling the engine,resulting in a rough idle.

4)Injectors have an unequal flow or spray pattern;
Do an injector flow test and replace any that do not
deliver the correct amount of fuel or have a poor spray pattern.

[NewmanP]

Hi Ron,
thanks for getting back to me with is info.
All of the injectors have been Flow test this past month no problems there.
They Air mass controller is new and been adjusted. Start right up run great
on the open road Plenty of power.

No Leaks on the Cold Start injector. ( that new as well )

The Lamba controller is new ( Rebuilt )
New Idle control valve

Let me as you this. I was going to pull the valve covers and look to see
if we have a compress seal or guides. Or due you think I have a bad 02 sensor

Thanks
Pete

[meltedpanda]

could be O2 sensor, I think that car had self adjusting vavles
If it happens only when warm and only at idle then I would look at air and fuel delivery at that time, throtle plate ( airflow sensor plate) adjustment or warm control pressures. have you checked the pressures? Warm should be 49-55psi

[ctaylor738]

Have you checked the duty cycle and adjusted the base mixture through the hole in the air cleaner? You can check it on Pin 3 on the diagnostic socket with an analog dwell meter (about 22 degrees on the 8 cylinder scale) or a DMM with duty cycle (around 50%). The adjustment is with a 3mm long-arm hex key wrench. Right rich, left lean.

No AAV on a 380, its electronically controlled.

You did replace the seals when you serviced the injectors?

Lots of posts on this.

[pmckechnie]

What kind of plugs does it have in it? Anything other than copper core non resistor plugs will cause idle problems.

Paul