codes p0171 p0174 need help asap!

gearhead06 · April 23, 2011

ok so here we go, I have the lean codes bank 1 and 2 p0171 and p0174, I have replaced the fowling the idle control sensor, upper and lower mani gaskets, new thermostat housing(it was leaking)...I have cleaned the maf sensor checked for vacuum leaks and I'm out of ideas and money... what else could be throwing these codes!!!!! I even had it in the shop and the mechanic didn't know were to start either and I already spent over $700 on this damn suv I cant afford much more... 2001 ford explorer sport 4.0 v6 sohc 4x4 200,000miles please help...

thanks

gearhead06 · April 23, 2011

also it starts hard in the cold thats why I replaced the upper and lower intake mani gaskets... but still throws the colds even on warm days...

rocco123 · April 23, 2011

Does it runn better or worse with MAF disconnected?

2000StreetRod · April 23, 2011

Stock intake system?

Is the engine intake system stock or do you have a breather installed on the right valve cover?

Have you checked the PCV valve hose connections to make sure they are all tight?

Did the lean codes show up after replacing the manifold gaskets? If so, you may have damaged the EGR O ring during removal or installation of the upper intake manifold. There are two different EGR O rings. One is significantly thicker (correct one) than the other.

Did you check the flexible elbow between the IAC valve and the semi-rigid tube that goes to the main intake hose?

gearhead06 · April 23, 2011

yes, the codes were present before the gaskets were replaced, and yes all hoses and tubes seem to be fine, I haven't detected any leaks anywhere, I have replaced everything listed above trying to correct these codes, I will try disconnecting the maf sensor tomorrow and see how it runs... thanks for the replies!

gearhead06 · April 23, 2011

o yea and everything is stock under the hood...

2000StreetRod · April 24, 2011

low fuel pressure?

Perhaps the fuel pressure is low. Has it been more than 30,000 miles since the fuel filter was changed? It could be clogged and restricting flow. Or your intank fuel pressure regulator could be faulty or your fuel pump could be weak. I suggest that you check the fuel pressure. It should be 60 to 65 psi at all times.

ziggy92 · April 24, 2011

I had a situation similar to yours about a month ago. I spent around $400 in parts alone replacing everything i could think of and i couldn't figure out what it was. It ended up being a valve underneath the battery that had a hole in it causing it to suck in air. I believe it was called a vapor management valve and wasn't very expensive. I would try looking from the hood underneath the battery and if you cant see anything from there then try taking off part of the wheel well to get a better look.

ncranchero · April 24, 2011

KCV190 PCV elbow, cracked, BOTTOM side.

gearhead06 · April 24, 2011

I didnt get to check the how it ran with the maf sensor unhooked yet I will tommorow and I will see if I can get a hold of a fuel pressure tester to, as for the cracked pvc pipe fitting I already checked for that and it must be a newer motor than mine because I dont have that line.. mines got that upper intake that has the big tubes on either side of it... they must have had 2 4.0 motors in 2001...

gearhead06 · April 24, 2011

also 2000StreetRod were is the fuel pressure regulator at? I tried looking up one at orielly and they didn't even list one for the truck...

ncranchero · April 24, 2011

gearhead06 said:
..........as for the cracked pcv pipe fitting I already checked for that and it must be a newer motor than mine because I don't have that line.. mines got that upper intake that has the big tubes on either side of it... they must have had 2 4.0 motors in 2001...

Yes there were. Yours is a Job 1 then. Do check those rear PCV hoses & tee though.

2000StreetRod · April 24, 2011

intank regulator

gearhead06 said:
also 2000StreetRod were is the fuel pressure regulator at? I tried looking up one at orielly and they didn't even list one for the truck...

As I mentioned in my earlier post the fuel pressure regulator is located in the fuel tank. The similar looking item on the fuel rail is the fuel pressure damper.

ncranchero offered good advice about checking the PCV valve connections. They are difficult to access with the upper intake manifold in place. My hoses were worn after years of rubbing against the firewall. I replaced the hoses and eventually installed hose clamps to prevent any leaks. SOHC PCV Valve Mod thru 2000

ranger7ltr · May 8, 2011

Check this out...

ziggy92 said:
I had a situation similar to yours about a month ago. I spent around $400 in parts alone replacing everything i could think of and i couldn't figure out what it was. It ended up being a valve underneath the battery that had a hole in it causing it to suck in air. I believe it was called a vapor management valve and wasn't very expensive. I would try looking from the hood underneath the battery and if you cant see anything from there then try taking off part of the wheel well to get a better look.

I replaced my engine last year and everything was running well...I started looking at replacing the old vacuum lines about a month ago and I started getting alternating lean bank 1 and 2 codes[P0171-P0174]...I looked at the data pulls from my scanner and the LTFT was going 20-30% especially around idle...I did everything I could think of and checking for vacuum leaks was part of that...I STILL had issues...

Until I replaced the vapor mgmt valve...After changing that, the vacuum lines, and resetting the data tables by pulling the battery cable for 10 mins. I now have a LTFT of less than 10 and the STFT is varying all over the place like I believe it should...Just off of idle the LTFT drops to 0 or near 0 and the STFT seems to be the compensation for added or removing fuel for the load...

Oh and the lean codes have got bye bye...

codes p0171 p0174 need help asap!

gearhead06

Member

gearhead06

Member

rocco123

Well-Known Member

2000StreetRod

gearhead06

Member

gearhead06

Member

2000StreetRod

ziggy92

New Member

ncranchero

Co-moderator

gearhead06

Member

gearhead06

Member

ncranchero

Co-moderator

2000StreetRod

ranger7ltr

Explorer Addict

Explorer Features

Explorer Features

Similar threads

Featured Content