mistermog

Hey guys,

Having an issue... both of these codes are showing up on me now. First P0171 shows up lean bank 1, then a few seconds later, lean bank 2 shows up.

Completely stock in regards to this issue, no intake or anything.

I checked all the intake parts last night and no leaks that I could see or hear.

O2 sensors are probably well over 100k miles, and I would assume the fuel pump is too.

Any suggestions on how/what to look at? I have the car in the air right now to see if I can see anything that mighta came loose under it, but other than that I'm at a loss.

Anything is helpful at this point, other items that could cause it? I've heard exhaust leaks or coolant temp sensors could cause lean codes?

lucky131969

Look for common things to both banks. Check air intake connections for security, leaks, etc. Also check vacuum lines for cracks/leaks.

mistermog

Yep, that was the first thing I did, took everything off last night checked hoses and reassembled everything. Nothing looked wrong. Reading the service manual it is leaning more toward fuel pump issues, which I would have to say makes more sense, but I don't have a way to test this without any special tools, do i?

lucky131969

Yep, you need a gauge attached at the fuel rail. Has your filter/regulator been changed?

mistermog

it hasnt been since ive owned it, the last 80k miles (from 90 to 170k).. thats what im leaning toward but have never done pressure tests before

lucky131969

So you potentially have 170k on a factory filter/regulator? Come on bro.....

mistermog

Hahah yep, which is why I'm not surprised if it would be that, obviously. But looking for how to test this out before I go parts shopping.

lucky131969

You need a fuel pressure gauge, that you can get at most autoparts stores. I never advocate just changing parts, but I would change that filter no matter what given the circumstances.

mistermog

Very likely what I was going to do anyway... I looked at it and not sure how to get the fittings off...

I've never done fuel line connections before?

lucky131969

There are a few threads out there covering it, but again, you'll need the correct tools. You might just be better off having it done.

mistermog

Possibly, I'm not an mechanic but I am an engineer... and we like to try until we break something

lucky131969

Wow, an engineer, huh? A smart person like you should have no problem changing a fuel filter.

mistermog

I didnt say I was a good one I looked up under the car and I just haven't seen it before, not sure what kind of connections they are. once I know how itll be cake.

I just hope this is the issue, a buddy has a fuel pressure gauge set so I might look into that first.

Jnape

A good tool is essential. I have not used one, but here is one example. They are quick disconnect lines, no clamps you would recognize.

http://www.autopartswarehouse.com/de...9QQOT7370.html

mistermog

would the old 'ford AC tool' thing work with this if its the same quick disconnect?

byronhunter

Yep, same thing if you got the correct size.

mistermog

Groovy... so I'm seeing all kinds of prices when I look this up, advance auto parts has them for 30 bucks, but ecklers is 100... with that much swing theres gotta be something different between the two... but they look the same?

mistermog

ok, while im here, to check fuel pressure... hook the guage to the port on the rail and disconnect a vacuum source to the rail, correct?

should see between 55 - 61 psi... if the regulator by the tank is crap, itll be lower right?

crainholio

Should see a nice steady 58psi with the engine idling. Fuel pumps tend to be very binary...they go straight from making full pressure to dead as a doornail.

It's been my experience that the integrated filter/regulator, on the other hand, degrades in a more linear fashion and gradually reduces net pressure at the rail.

Any reading less than steady 58psi at the rail, replacing the filter/regulator is recommended step 1.

mistermog

Is that how I should check it though, connect it to the rail port, disconnect some vacuum line, and measure there at idle.