91 Talon running rich

[bstclum]

Ok last month I broke my timming belt and as you all know the head was shot. I replaced the head and found out that the knock sensor was shot. I'm driving and I noticed that the car runs rich on my a/f meter. Could the knock sensor being bad make the car run rich? every thing else is perfect the timming and everything? Any insite would be great!

 

[donmagicjuan]

I believe a non-functioning knock sensor will cause the ECU to go into a safe mode, but I'm having trouble digging up exactly what this would entail. You would also have a CEL for the sensor. It is very ill-advised to drive around without a knock sensor, however, because the ECU has no way of protecting the engine against the problems associated with detonation. Probably not the answer you were looking for, but it's the best I can do at the moment.

One other thing to consider is that a typical blinky-light AFR meter is just about worthless. Unless this is a sudden change, I wouldn't put too much stock into what it's telling you.

 

[bstclum]

It was a sudden change. Before I broke the timming belt the A/F meter was working properly I know that I have a boost leak on the intake hose that goes to the bye pass valve (will fix today) Could that make it run rich? And I have another question. I did a compression test on it and this is how it read from #1-#4 90,150,150,145. I know that i need new rings. Could this being so off make it run rich?

 

[donmagicjuan]

Yikes, it sounds like you have a few problems to work out. A severe boost leak will definitely cause you to run noticeably rich under WOT. I'm not sure about the bad compression number on cylinder #1, it depends on what's going on inside it. Did you do a wet test following those results to confirm it is the rings on that cylinder?

 

[bstclum]

yeah i did a wet test and i'm sure it's the rings. For some reason i just noticed my plugs and they are grey as far as I know the plugs should be a brownish color right? I fix the boost leak but nothing helped. what color are the plugs suposed to be?

 

[missouri_dsm]

bad oxygen sensor would definately cause a rich condition.

 

[donmagicjuan]

Depending on the additives in your fuel, it's hard to say exactly what color the plugs should be. Light gray is supposedly ok. As long as they're not white, black, or oily, and you don't see any signs of knock, you're probably alright. You can google "spark plug reading" for some more in-depth information.