95' 960 idling problems

[awdsubaru]

Hello All,

First post here. I have used your site and its excellent resources for my car in the past, and it has helped out tremendously. All of your post's and information has been greatly appreciated.

I recently had some issues with my 960. The check engine light came on. I checked the codes with the diagnostic probe and
212 221 232 & 241 came up. My car obviously failed the Canadian emission test, it was very high in hydrocarbons & nox.

In my past with cars that have a OBD 2 port, I have just cleared the codes and see what happens. So I tried that. I killed all the codes. I started up the car, and WOW it idles like crap. One minute prior the car ran perfectly! Now it is idling horribly, basically choking and puking for a few minutes, if I rev it up for about 2 minutes or so, the idle seems to level out, and the car can finally be driven. It seems to be trying to learn the idle again. The trouble is that EVERY time I start the car, this happens again. It seems to not be able to learn the mixture or idle it needs. I have now driven the car about 800km since clearning the codes and no warning lights have come back on.

So today, I decided to do some work on the car, and I started with trying to clean most of the emission/oxygen componenets of the car. I have changed the spark plugs, changed the oil, cleaned the MAF, cleaned the air filter, took apart the throttle body, took the intake manifold off of the car, in order to get to the EGR valve. I cleaned everything, there appears to be no breaks or cracks on any of the hoses. The EGR functions properly. I even took apart the o2 sensor electrical connection in the engine compartment, and cleaned the connectors. I have not looked at the o2 sensor(s) yet. I ran out of time today! I just thought that since all of the work I had done today, I would have noticed some improvement. It does have more acceleration/power, but the idling problem still exists, no improvement there.

Any suggestions of what I should look at next would be greatly appreciated.

If its worth mentioning, my car has 419,000km!

[precopster]

Welcome to MVS. The ICV or idle control valve MAY be a suspect but given that 3 of 4 of these codes relate to O2 sensor it's unlikely.

Looks like the heater element in the O2 sensor has broken. When you unplug it there should be around 6 ohms across 2 of the terminals; this is the heater coil. Is it a 4 wire sensor?

When the car starts from a stone cold start does it idle OK? It takes around 20 seconds for the management system to switch over to O2 control. After that time you will get very poor idling if the O2 sensor is bad.

[awdsubaru]

You nailed the starting issue on the head. It start perfectly normal for the first 10 seconds or so, and then starts to choke and idle really roughly. It never does stall, just takes a good 2-3 minutes of giving it gas, and letting it warm up for the car to start to idle normally. I bought a second hand ICV today and o2 sensor, I will try to replace those tomorrow and see how it goes. Thanks for the help!