munsonbw

I have searched the archives, but I thought before I spend a lot of time looking at every component of my system, I would see if someone has had a similar problem.

The car is an 81 euro spec with the lambda system. The problem is with idle hunting at a rather quick pace. When it is 80+ degrees out, it doesn't really hunt, when it is 60 degrees it will do this for quite a while (maybe a minute or two). The other problem, which I think is related, is in any weather after the car has been run but sitting for 10-20 minutes will not stay running. The idle lopes very hard at around 500 rpm then just falls off.

My first guess was the WUR based on the archives.

Thanks,
Ben

Peter Zimmermann

Info please. When was the last professional tune up/maintenance? Do you use premium fuel? What do you have the fuel mixture set at? Does the car have a catalytic converter? Etc., etc...
Pete

Steve Weiner-Rennsport Systems

I'd add to Pete's questions,..

How old is the oxy sensor? Thats a common cause of idle problems on cars with Lambda control.

CDiercks

Just curious... if it's an 81 euro, why does it have the lambda system? No euro SC's came with an oxygen sensor that I am aware of. Was it added when it was brought to the US?

munsonbw

I am not sure if the car has a cat or a pre-muffler. The car was a grey market car, so I am guessing it was added to meet US emmisions. The last professional tuneup was over 5 years ago and the mixture settings are not something that I have checked or have the equipment to do now. I have not replaced the O2 sensor in the 5 years I have owned the car, is there a test to check them? Assuming mine is a conversion car, how will I determine which O2 sensor I need or are they all the same except for size? And I always use 92 octane.

Edit: I just took a better look at my car. There is not an O2 senson anywhere that I can see. There is a bung right before the cat (or premuffler?) that is capped off. With that said, what is regulating the operation of the frequency valve? Can I just bypass the valve, or will that mess up the settings? I really don't care to have the lambda circuit, as many other SCs did not have it, but I really don't understand its operation.

Thanks,
Ben

recordmanv

I am no expert, but I doubt it's the O2 sensor. I run my daily driver SC with my O2 sensor always disconnected and my idle is rock solid, sits at 900. Never hunts. It could be a million things, I would bet it's a vaccum leak, bad fuel/air mixture, bad spark plugs, fuel, distributor, rotor timing, etc. I don't know how often you drive, but I get a tune-up with my major services every 15k miles, which is about every 8 months. I use CA 91 oct.