Schuck's pulled the following codes from my truck today:

P1131
P0171
P0133

Can someone decipher these for me? One of the employees and myself found that one code stated a dying O2 sensor on Bank 1 (something that had popped up before) and that the truck was running lean, which I assume is caused by the failing sensor. Anything else I should be aware of? Also, is Bank 1 the left 02 sensor?? Thanks for your help!

Andrew
Boise, ID

 

Bank 1 is on the right (pass. side). Most O2 sensor codes don't mean you have a bad sensor. It sounds like you may have a vacuum leak causing the lean code.

 

All the codes are consistent in that they indicate Bank 1 (passenger side) lean. I agree that you should look for vacuum leaks first which could be allowing unmetered air into that side of the engine.

Look Up Ford OBD-II Trouble Codes

 

Hmmm...so you think I bought an 02 sensor for nothing then? And, excuse my ignorance I'm a beginning mechanic, what's the best way to check for such leaks and where do I start??

 

the best thing to do is get a vaccum pressure gauge from autozone or the like and test the vaccum at the intake manifold tree where all the vaccum lines come together. a steady reading from around 18 to 21 inches indicates a sound engine.

 

Examine all the vacuum hoses coming off the upper intake, make sure none are damaged or pulled off. They ltend to get brittle over time, especially at the ends.

A vacuum gauge is a good idea, too.

This will give you a general idea of why and how to check for vacuum leaks:

http://www.aa1car.com/library/vacleak.htm

 

If you don't find a vacuum leak, leans can also be caused by a dirty or malfunctioning fuel injector. Search the forums for tips in this area. Careful about overloading your tank with injector cleaner. Some tanks have a metalic lining that can break down and go through a filter and foul your plugs. Ford would be the place to ask if your tank has such a liner. Caddy's do for instance. I am not sure Fords do.

 

^^^^^^^^^^ That reminds me of a question I was meaning to post on here. Bit of a story to it:

Long story short. I got a gift certificate at Christmas to a garage here in town for an oil change. I have used the shop before and found them quite reputable. They were recently bought out by another fellow and underwent a few changes. Some of the same people and prinicples are there so I decided what the heck and give it a shot. It was free ya know?

So I take my truck for one of the quick oil changes and they say they inspect the truck, lube the chassis, top off all fluids, etc etc. So when they wre through (a mere 20 minutes or so later) the mechanic came and gave me his "report". He said that the brakes were 85% worn and the radiator needed flushing and that the fuel filter was going bad. So I said "ok thanks" and headed out. I took care of the radiotor flushing myself and meant to ask on FTE about the fuel filter. Do you think the fuel filter itself could be causing the CEL to come on and report a lean? If so is this solved with some sort of cleaner or does the filter itself have to be replaced??

Thanks again for you help guys I really, really appreciate it!!

 

i doubt that a bad fuel filter will cause the CEL to come on but maybe i could cause the engine to run lean. the filter itself needs to be replace if it is bad. if it has not beed changed in a while you might consider changing it anyway.

 

Yes, a bad filter WILL cause a lean CEL code.

ANY part that causes a loss of fuel in the air/fuel mix needs to be considered....which is why the O2 sensor itself is rarely the issue in these cases. It only measures oxy in the exhaust. Nothing more.

 

I think a bad fuel filter/low fuel pressure would give a lean condition for both banks.

 

I am about to do battle with a lean code as well Caplax40. I feel your pain.

 

So do you think that since only Bank 1 came up, that it's NOT the fuel filter? Is it safe to say that? I know for a fact that as long as I've had the truck (almost three years, about 16k miles) that it has not been changed.

So are we back to the vacuum leak???

 

Vacuum leaks are not that common on the 3.0, like they are on the 4.0OHV, but thats were I would start. If you have a fuel pressure gauge it never hurts to test it, then you know for sure and its so easy.