Another P0171 & P0174 thread
Thread Starter
|
Cross-Country
Joined: May 2006
Posts: 69
Likes: 0
Another P0171 & P0174 thread
2001 Navigator
-- lean codes on both banks
-- high idle (950 RPM)
-- RPM's stay high for a long time when I let off the gas pedal, comes down very slowly.
-- LTFT in both banks stay at 29% all the time, all RPM's/Speeds
-Cleaned MAF with maf cleaner
-No apparent vacuum leaks -- going to do a smoke test when I get a smoke machine.
Any ideas would be appreciated.
Solved: See post #7, PCV End Elbow
-- lean codes on both banks
-- high idle (950 RPM)
-- RPM's stay high for a long time when I let off the gas pedal, comes down very slowly.
-- LTFT in both banks stay at 29% all the time, all RPM's/Speeds
-Cleaned MAF with maf cleaner
-No apparent vacuum leaks -- going to do a smoke test when I get a smoke machine.
Any ideas would be appreciated.
Solved: See post #7, PCV End Elbow
New User
Joined: Jun 2016
Posts: 19
Likes: 0
Ran into the same thing with mine, it would come and go throwing the lean code. Ended up being a few of the vacuum lines around the battery tray and under one of the main harnesses were rotted enough to cause a small leak. Only noticed them because I had to move them out of the way while changing the spark plugs. After replacing them I haven't any codes in close to a year.
On unrelated note changing the plugs is a pain on the 4 valve, very little room to work
On unrelated note changing the plugs is a pain on the 4 valve, very little room to work
Thread Starter
|
Cross-Country
Joined: May 2006
Posts: 69
Likes: 0
I'm thinking now I damaged something vacuum-related when I did that. Because those codes appeared soon after I replaced the COPs and plugs last year.
The smoke test I'm gonna do will let me know hopefully.
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
It's either a vacuum leak or a failed IAC valve.
Vacuum leaks are almost always in the PVC system (90+% if the time), check it completely from end to end, especially that elbow around back.
If you have a scan tool that can show either the short term fuel trims or the upstream O2 sensor voltages, use the "spray and monitor" method. I use brake parts cleaner since it's cheap and readily available. Finding or making a smoke machine is a PITA when there are easier methods available.
Vacuum leaks are almost always in the PVC system (90+% if the time), check it completely from end to end, especially that elbow around back.
If you have a scan tool that can show either the short term fuel trims or the upstream O2 sensor voltages, use the "spray and monitor" method. I use brake parts cleaner since it's cheap and readily available. Finding or making a smoke machine is a PITA when there are easier methods available.
Fleet Owner
Joined: Apr 2008
Posts: 24,316
Likes: 5,127
From: 0,0,1
Logistics Pro
Joined: Jan 2001
Posts: 3,740
Likes: 37
From: Central NYS
Yep. And if it's not the IAC, try pinching off the PCV hose to see if the idle comes back down quicker.
(We had a 2005 3.0 Sable in my son's '98 SVT and after a year or so the IAC couldn't control the idle. Finally found the PCV was gooked (trademark) up and wouldn't open and close consistently. Fun time trying to change the PCV without pulling the intake manifold.
)
(We had a 2005 3.0 Sable in my son's '98 SVT and after a year or so the IAC couldn't control the idle. Finally found the PCV was gooked (trademark) up and wouldn't open and close consistently. Fun time trying to change the PCV without pulling the intake manifold.
)
Thread Starter
|
Cross-Country
Joined: May 2006
Posts: 69
Likes: 0
So I bought one of those $80 smoke machines off ebay to find something right in front of my face. Oh well, now I own a smoke a machine. And another $100 for a Bluedriver scanner.
PCV End Elbow $8
Dorman - Help PCV End Assembly 46017: Advance Auto Parts
If you look closely in the pic below you'll see a wisp of smoke emitting from the left side of the elbow.
Trending Topics
Logistics Pro
Joined: Jan 2001
Posts: 3,740
Likes: 37
From: Central NYS
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
Thread Starter
|
Cross-Country
Joined: May 2006
Posts: 69
Likes: 0
Yes. Idle is in the normal 700's now. Plus, the high idle doesn't hang up when you tap the gas pedal. So all seems fine except the high LTFT values during a short test drive. I'm thinking it will take a few miles of driving for the computer to fully re-adjust the trims.
But for the heck of it, I'm going to do the Idle Re-Learn process today.
But for the heck of it, I'm going to do the Idle Re-Learn process today.
Thread Starter
|
Cross-Country
Joined: May 2006
Posts: 69
Likes: 0
This is the unit I bought.
EVAP/Vacuum Smoke Machine Diagnostic Emissions Evaporative Leak Detector *New* | eBay
The only problem I had was the quick connect fitting was different from my workplace's airline fittings, so I had to swap the connector.
It's basically a paint can, a 12V heating element, a barbecue grill propane pressure regulator, a hose, 12V clamp cables, and a couple of fittings.
People on youtube make these things all the time. I figured $80 was worth it. It works.
Logistics Pro
Joined: Jan 2001
Posts: 3,740
Likes: 37
From: Central NYS
This is the unit I bought.
EVAP/Vacuum Smoke Machine Diagnostic Emissions Evaporative Leak Detector *New* | eBay
.
EVAP/Vacuum Smoke Machine Diagnostic Emissions Evaporative Leak Detector *New* | eBay
.
I like that 100% feedback!
(My buddy sold his Redline smoke machine that I had use of,
and the one I made from a Cummings glow plug and a big oil can
keeps burning my fingers,
, so I'm gonna look at this also.)
Fleet Owner
Joined: Apr 2008
Posts: 24,316
Likes: 5,127
From: 0,0,1
Thread
Thread Starter
Forum
Replies
Last Post
gushauler
1997 - 2006 Expedition & Navigator
8
Jan 22, 2018 11:37 PM
sethrich89
1997 - 2003 F150
18
Jul 16, 2017 08:33 PM