Check Engine Light
Thread Starter
|
Junior Member
Joined: Mar 2003
Posts: 3
Likes: 0
From: Orange county
Check Engine Light
I have a 96 F150 4X4 300cu.in 6cyl manual trans. The CHECK ENGINE lite came on. I bought a code reader. The code reader said P0171 & P0174. 2 seperate codes. The codes mean sensor 1 and 2 are TOO LEAN. I erase the codes and they come back in a day or two. I made the SUPER UN-INTELLEGENT decision to take the truck to the dealer. After $750.oo dollars and a new mass air flow senser and new plugs and wires- - - GUESS WHAT ? ? ? One day later the CHECK ENGINE LITE came on again ! ! ! NOW WHAT ? ? ? Any one have a similar experience ? PLEEEZE HELP ME
Technical Article Contributor
Joined: Oct 2003
Posts: 1,490
Likes: 0
From: Topeka Kansas
Look at the Possible Causes column for code P0171 here.
http://www.v8sho.com/SHO/TSB0197HO2SServiceTips.htm
QUOTE:
Fuel System:
· Contaminated fuel injectors
· Low fuel pressure or running out of fuel (fuel pump, filter, fuel supply line restrictions)
· Vapor recovery system (VMV)
Induction System:
· MAF contamination
· Air leaks between the MAF and throttle body
· Vacuum leaks
· PCV system concern
· Improperly seated engine oil dipstick
EGR System:
· Leaking gasket
· Stuck EGR valve
· Leaking diaphragm or EVR
Base Engine:
· Exhaust leaks before or near the HO2S
· Secondary air concern
Powertrain Control System:
· PCM concern
http://www.v8sho.com/SHO/TSB0197HO2SServiceTips.htm
QUOTE:
Fuel System:
· Contaminated fuel injectors
· Low fuel pressure or running out of fuel (fuel pump, filter, fuel supply line restrictions)
· Vapor recovery system (VMV)
Induction System:
· MAF contamination
· Air leaks between the MAF and throttle body
· Vacuum leaks
· PCV system concern
· Improperly seated engine oil dipstick
EGR System:
· Leaking gasket
· Stuck EGR valve
· Leaking diaphragm or EVR
Base Engine:
· Exhaust leaks before or near the HO2S
· Secondary air concern
Powertrain Control System:
· PCM concern
Senior Member
Joined: Oct 2002
Posts: 7,295
Likes: 125
From: St. Louis (Out in the woods)
Originally Posted by Tim Sommerville
I have a 96 F150 4X4 300cu.in 6cyl manual trans. The CHECK ENGINE lite came on. I bought a code reader. The code reader said P0171 & P0174. 2 seperate codes. The codes mean sensor 1 and 2 are TOO LEAN. I erase the codes and they come back in a day or two. I made the SUPER UN-INTELLEGENT decision to take the truck to the dealer. After $750.oo dollars and a new mass air flow senser and new plugs and wires- - - GUESS WHAT ? ? ? One day later the CHECK ENGINE LITE came on again ! ! ! NOW WHAT ? ? ? Any one have a similar experience ? PLEEEZE HELP ME
Take it back.
The repairs they made were not effective.
Insist on a credit for the stuff and time that you paid for that did not correct the problem.
Most likely a vacuum leak...
Steve
Technical Article Contributor
Joined: Oct 2003
Posts: 1,490
Likes: 0
From: Topeka Kansas
Originally Posted by projectSHO89
Take it back.
The repairs they made were not effective.
Insist on a credit for the stuff and time that you paid for that did not correct the problem.
Most likely a vacuum leak...
Steve
The repairs they made were not effective.
Insist on a credit for the stuff and time that you paid for that did not correct the problem.
Most likely a vacuum leak...
Steve
Technical Article Contributor
Joined: Jun 2002
Posts: 10,511
Likes: 10
From: Under the flightpath of old ORD 22R
Originally Posted by projectSHO89
Yeah, I'm a crabby bastard when it comes to getting screwed on repairs....
More like paying for something you did not get ??
I can see that one, paying 750.00 for a day without your truck ( and that is it ) is not a good thing in my mind either.
Steve
Junior Member
Joined: Nov 2004
Posts: 4
Likes: 0
Tim...its a vacuum leak
Tim,
I had the exact same problem and there are two possibilities.
there is a vacuum hose (elbow shaped) under the very middle part of the "U" on the intake manifold...it is a bitch to get to unless you have small hands, but most likely the elbow has deteriorated and is letting excess air into the intake causing the fuel rail too lean readings...replace it $12 at the dealer.
second...there is another vacuum hose on the very back ( your left) corner of the intake manifold (as you are standing looking at the engine) one end attaches to the manifold and the other attaches to a nipple on the PCV valve.
Check it for deterioration as well and also with the engine running check to see if is collapsed along all or part of its length...replace it as well...
then disconnect the battery cable for a few minutes so the codes will clear and then start her up...your problem should be fixed.
I had the exact same problem and there are two possibilities.
there is a vacuum hose (elbow shaped) under the very middle part of the "U" on the intake manifold...it is a bitch to get to unless you have small hands, but most likely the elbow has deteriorated and is letting excess air into the intake causing the fuel rail too lean readings...replace it $12 at the dealer.
second...there is another vacuum hose on the very back ( your left) corner of the intake manifold (as you are standing looking at the engine) one end attaches to the manifold and the other attaches to a nipple on the PCV valve.
Check it for deterioration as well and also with the engine running check to see if is collapsed along all or part of its length...replace it as well...
then disconnect the battery cable for a few minutes so the codes will clear and then start her up...your problem should be fixed.