HEGO fault codes.....what now??

[Diameg]

Today my Check Engine Light came on. I turned the car off and it did not reappear.
The light came on shortly into a drive on a very cold day, with a not so warmed up car.
In checking my codes, I got 172 (Heated Oxygen Sensor fault/lean bank #1) and 176 (Same thing, bank #2). These were both in the Continuous Codes.
For KEOE, I got my usual 511 (expected), and 114 which also appears when I have my LPM in. Without the LPM, I don't get that code.
For KOER, I got 111 (all clear).

Are those 172 and 176 codes something I should worry about? My concern is that my car is running lean, although my dyno graph does not point to that.

Should I start playing the 'What do I have to replace now' game that always seems to accompany these cars, or just not worry about it?

 

[sdpatt]

With both O2 sensors indicating lean, you most likely have a lean mixture condition. The probablilty of both sensors failing simultaneously in the same manner are very slim. The 114 indicates that the air charge temperature sensor is producing a voltage out of the expected range. I would check the connector on the ACT sensor in the air filter box and replace the sensor if the connector was attached. After resolving the ACT problem, clear the codes and run the KOEO test again.

 

[Diameg]

Scott,

I have tried everything to get rid of that 114 code including cleaning the wires, checking the voltage to the wires, and replacing the ACT sensor. Code will not go away.
When I take my LPM out, the code goes away.

I was afraid of that 'running lean' thing. It was just yesterday that I got the Check Engine Light and the 172/176 codes. They were in KOEO continuous codes. For KOER, I did not get them.
Should I be very worried about that? I of course do not want to run lean, but have not seen those codes come up before or after that one time.

Could a running lean condition be related to the ACT sensor situation?
Again, I don't know how to get rid of that 114 code without taking the LPM out. Since it is only evident with the LPM in, I figured it is just a conflict somewhere in that.

 

[sdpatt]

I bad signal form the ACT sensor can definitely cause a lean or rich fuel mixture. I have seen and heard of the 511 code due to an LPM, but never the 114 code. There may be a problem with the LPM.

Have you cleared the memory codes by disconnecting the test jumper while the error codes are being output?

Scott

 

[Diameg]

Yes, I've cleared the codes so many times on my car that I believe I've given it a full lobotomy.

Darn it, now I don't know what to do.
I will try and clean the ACT again, but I don't think there's anything wrong with it since I have cleaned, and then replaced, the sensor.

I have no idea how the LPM can have an effect on the ACT (mostly because I simply don't know enough about that kind of stuff), but all I know is that with the LPM in, I get the code all the time. With it out, I do not get the code at all. I had figured that it was just like the 511 code and perhaps was a byproduct of the computer override, but I guess I had better try and find out what is going on with that.

Darn it (once again).

 

[twr]

Mike,
Are you still fighting your idle problem too or has that been solved?? I still think your LPM might be the root of the problem.
Terry

 

[Diameg]

Terry,

Not really. Funny thing is, I was at Sho Nut Performance and Josh did a coolant flush, new T-stat, and drilled a drain plug in my tranny.
I put the LPM and MAF back on (had them in the trunk at the time) to see if he had any ideas, and sure enough it idled smooth (ish).
That lasted for a couple of days, and then it was back to the idle thing, although it's not as bad as before.
Yesterday was the first time I got a Check Engine light though, so now I'm really worried.
I know the best thing would be to dyno it at a place that has A/F but it's also getting expensive at $50 a pop!
Aye Carumba.....

Mike

 

[twr]

Mike,
Get a a/f meter (autometer) - they are pretty useless during normal driving (bouncing from lean to stoich, kinda cool looking), but when you go to WOT it reads fairly acurately (in my experience) - atleast to the point of knowing if you are running very lean or very rich. That's how I found that I was running lean with the original lpm programming.
Terry burn_out

 

[Diameg]

Terry,

Okay, is there a part number or anything like that for the one I want? I checked on their site a while ago and came away with more questions than answers.
Also, how do they hook up?
Thirdly, where is a good place to mount the guage? I don't want one of those pillar guage pods. Can they go anywhere or do they need to be there for some bizarre reason (like not looking down while driving 118 miles per hour....)

 

[Sho-N-Go]

normally when you get a lean code on both banks you need to look at the MAF it is norm the prob. you may also have a vaccum leak these two issues must be looked at seriously.

 

[white94sho]

I have been getting the same codes on my 94 atx when it is cold out. Also I have only gotten 145 miles on the last tank of gas, car took 16 gallons to fill. which is only 9mpg so what is the problem here.

 

[Diameg]

toolboy79:
normally when you get a lean code on both banks you need to look at the MAF it is norm the prob. you may also have a vaccum leak these two issues must be looked at seriously.

The lean codes were in Continuous code only, and only caused the CEL to come on that one time.
My KEOR test and KOEO tests since that time do not throw those codes, only the above mentioned 511 and 114.
How serious is it? Should I not drive it until I find out what's going on?
Of note, I have tried 3 different MAF's including one from a friends perfectly running Lincoln Mark VIII to try and solve my idle problem. The car was exactly the same with all 3.
In theory, I could try another MAF but I feel it would be very unlikely that the 3 MAF's I tried all were faulty, especially since the one I tried was from a car I drove all that day (Lincoln).

How would I check the MAF to see if it's okay? Is there a way?
Are there any other causes for the lean codes?
Man, this is getting tiring really fast.