Contour Enthusiasts Group Archives Forums Modifications Duratec Maintenance Question about a part I haven't heard of....

Ok well I finally broke down and took my CSVT to a friend of the family who is a mechanic. The car had codes thrown that was saying both banks running rich and I already did the basic stuff like cleaning the MAF and checking for leaks and whatnot so I had this guy look at it. Finally after looking at it all day he is pretty sure he found the problem. According to my stepfather who talked to the guy said that he was told that it was a mass oxygen sensor?? I have never heard of this, is this just a term for something else. Basically what he was getting was that it was supposed to read around 0.7 volts at idle which it was reading, but when at WOT it was supposed to read 4.0 volts but would only get right around 2 volts max.

Anyway, I was wondering if any of you know what it is he may be talking about because I haven't got a chance to talk to him in person yet and my step father doesn't really know much about cars so he couldn't explain anything. Hopefully that would be my problem though and fixes the stupid CEL.

The Mass AirFlow Sensor reads from 0-5 volts. (i.e. the MAF)

It should be around 1 volt at idle.
4 volts is a good average for WOT at 6-7k rpm.


An Oxygen sensor reads from 0-1 volts.

It should normally dance back and forth around .45v very quickly under light load. It should be .8v to .9v at WOT.

No offence, but the dude is no mechanic, huh.

Check your fuel pressure yet?

Well like I said, my stepfather could have relayed the message incorrectly. I will find out today when I go pick the car up I guess. As long as the problem is fixed I will be happy cause I have spent forever trying to find the problem.

Anyway, thanks guys.

Those voltage readings sound like a throttle position sensor. It's mounted on the throttle body and reads the actual throttle plate postion. It really is the only sensor that that can read actual idle and wide open throttle postion. I'd have to check to be sure with the Contour, but with most cars the TPS idle setting should be .7 volts at idle. In fact, a common "mod" or "correction" for most fuel injected vehicles is to modify the TPS to .7 volts at idle(which is spec for most cars) because from the factory they can be as low as .4 volts. Dodge is notorious for this.

As far as running rich, 2 volts at WOT would lean out the fuel, but I guess it is possible that the PCM is over compensating and causing the O2 sensors to read rich.

TPS is .90v to .95v at rest. (closed/idle/etc)

TPS is 4.5v to 4.6v at WOT.

Ok well I went and talked to the guy today and it was the MAF that he replaced which is what I would have guessed. It wasn't reading more than 2 volts before and now with the new one it reads over 4.

Now the bad thing is that although that was obviously a problem, it didn't fix the stupid CEL....so I am going back again next week and he is gonna take a look at the intake gaskets and fuel pressure. I just wish I had time to look at this all myself, plus I don't have any heat in my garage so that makes it a pain too.

Thanks again guys