Vacuum leak. Maybe Evap?
Thread Starter
|
Posting Guru
Joined: Jun 2003
Posts: 2,314
Likes: 0
From: southwest michigan
Vacuum leak. Maybe Evap?
Super Duty in my sig. It had many issues when I first bought it, and I've ironed out several. The one persistent issue I have not been able to track down is the lean code that comes back every now and again.
The HVAC system always switches around when the engine is loaded, and the truck almost stalls when you put it into gear, to me all of this sounds very much like a vacuum leak. I was changing the oil today, and thought I would do a little looking around while I was waiting for the oil to drain.
I started wondering if there might be a leak in one of the EVAP lines, as I had to fix a line that had crumbled from age on my mountaineer (also a 2000) just last December.
Upon tracing the lines, I see that they alternate back and forth between rubber sections and metal sections. As I suspected, some of the rubber lines were very dry rotted, but it seems my issue goes beyond just the rubber lines. Most of the metal lines are extremely rusted. Some sections are so bad, it looks like it's growing barnacles.
This truck is not a DD, and doesn't have to meet emissions. I'm wondering if I can disconnect and plug the system in hopes of alleviating the lean condition, or will this further confuse the computer?
The HVAC system always switches around when the engine is loaded, and the truck almost stalls when you put it into gear, to me all of this sounds very much like a vacuum leak. I was changing the oil today, and thought I would do a little looking around while I was waiting for the oil to drain.
I started wondering if there might be a leak in one of the EVAP lines, as I had to fix a line that had crumbled from age on my mountaineer (also a 2000) just last December.
Upon tracing the lines, I see that they alternate back and forth between rubber sections and metal sections. As I suspected, some of the rubber lines were very dry rotted, but it seems my issue goes beyond just the rubber lines. Most of the metal lines are extremely rusted. Some sections are so bad, it looks like it's growing barnacles.
This truck is not a DD, and doesn't have to meet emissions. I'm wondering if I can disconnect and plug the system in hopes of alleviating the lean condition, or will this further confuse the computer?
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
While the EVAP system can cause a vacuum leak, it's way down the list of the usual suspects.
Start with the most common faults, in order:
PCV hose elbow
PVH solenoid
Spaghetti tubing near battery
Those three will probably account for 90%+ of vacuum leaks.
and the rest:
Vaccuum reservoir
HVAC controls
etc
Start with the most common faults, in order:
PCV hose elbow
PVH solenoid
Spaghetti tubing near battery
Those three will probably account for 90%+ of vacuum leaks.
and the rest:
Vaccuum reservoir
HVAC controls
etc
Thread Starter
|
Posting Guru
Joined: Jun 2003
Posts: 2,314
Likes: 0
From: southwest michigan
I guess I should have mentioned, I did replace the PCV hose elbow shortly after I got the truck. The old one was good but since I bought it to change while I was changing out the PCV valve, I went ahead and changed it anyway.
I never considered the PVH before. In fact, I was very ignorant about how these even worked until I started reading about them today. I knew the truck had vac lines running down to the hubs, and I made the assumption that the truck must have had auto lockers and the PO swapped them out to these manuals. Didn't know that an auto hub with manual override even existed.
After work, I pulled the line that feeds the PVH solenoid at the T, attached a 2" piece of fuel line to the T, then used a screw with liquid electrical tape in the treads to plug the other end of the fuel line. The truck still seems to bog when it's put into gear, but the code has not come back yet. I expect it will come back in a few days, like it always does.
Looks like I'll have to borrow a mighty vac and narrow it down. Thanks projectSHO89, I appreciate you pointing me towards the likely suspects.
I never considered the PVH before. In fact, I was very ignorant about how these even worked until I started reading about them today. I knew the truck had vac lines running down to the hubs, and I made the assumption that the truck must have had auto lockers and the PO swapped them out to these manuals. Didn't know that an auto hub with manual override even existed.
After work, I pulled the line that feeds the PVH solenoid at the T, attached a 2" piece of fuel line to the T, then used a screw with liquid electrical tape in the treads to plug the other end of the fuel line. The truck still seems to bog when it's put into gear, but the code has not come back yet. I expect it will come back in a few days, like it always does.
Looks like I'll have to borrow a mighty vac and narrow it down. Thanks projectSHO89, I appreciate you pointing me towards the likely suspects.
Postmaster
Joined: Aug 2012
Posts: 2,737
Likes: 23
From: Westfield, Indiana
I guess I should have mentioned, I did replace the PCV hose elbow shortly after I got the truck. The old one was good but since I bought it to change while I was changing out the PCV valve, I went ahead and changed it anyway.
I never considered the PVH before. In fact, I was very ignorant about how these even worked until I started reading about them today. I knew the truck had vac lines running down to the hubs, and I made the assumption that the truck must have had auto lockers and the PO swapped them out to these manuals. Didn't know that an auto hub with manual override even existed.
After work, I pulled the line that feeds the PVH solenoid at the T, attached a 2" piece of fuel line to the T, then used a screw with liquid electrical tape in the treads to plug the other end of the fuel line. The truck still seems to bog when it's put into gear, but the code has not come back yet. I expect it will come back in a few days, like it always does.
Looks like I'll have to borrow a mighty vac and narrow it down. Thanks projectSHO89, I appreciate you pointing me towards the likely suspects.
I never considered the PVH before. In fact, I was very ignorant about how these even worked until I started reading about them today. I knew the truck had vac lines running down to the hubs, and I made the assumption that the truck must have had auto lockers and the PO swapped them out to these manuals. Didn't know that an auto hub with manual override even existed.
After work, I pulled the line that feeds the PVH solenoid at the T, attached a 2" piece of fuel line to the T, then used a screw with liquid electrical tape in the treads to plug the other end of the fuel line. The truck still seems to bog when it's put into gear, but the code has not come back yet. I expect it will come back in a few days, like it always does.
Looks like I'll have to borrow a mighty vac and narrow it down. Thanks projectSHO89, I appreciate you pointing me towards the likely suspects.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 423
From: Long Island USA
The key here is that it sounds like your defroster comes on when you load the engine?
There is a check valve somewhere before the vacuum reservoir that should allow the reservoir to hold vacuum when the engine vacuum goes away.
If that check valve is bad, OR you have a leak somewhere else, that will allow the vacuum for the HVAC system to bleed off and disappear.
The reservoirs have been known to crack underneath where you can't see it.
Get a hand vacuum pump with a gauge and start testing things.
There is a check valve somewhere before the vacuum reservoir that should allow the reservoir to hold vacuum when the engine vacuum goes away.
If that check valve is bad, OR you have a leak somewhere else, that will allow the vacuum for the HVAC system to bleed off and disappear.
The reservoirs have been known to crack underneath where you can't see it.
Get a hand vacuum pump with a gauge and start testing things.
Fleet Owner
Joined: Aug 2010
Posts: 21,253
Likes: 1,656
From: Reynoldsburg, Ohio
Another quick test of sorts without using the pump gauge method.....
After the truck has sat an hour or so cycling the Function Switch through its Heat, Cool, Vent, Defrost etc settings will show if vacuum is being maintained as designed.
Not sure if the F-Series are as difficult to service as the E-Series for this situation but I hope not---those are just plain crazy impossible.
After the truck has sat an hour or so cycling the Function Switch through its Heat, Cool, Vent, Defrost etc settings will show if vacuum is being maintained as designed.
Not sure if the F-Series are as difficult to service as the E-Series for this situation but I hope not---those are just plain crazy impossible.
Trending Topics
Thread Starter
|
Posting Guru
Joined: Jun 2003
Posts: 2,314
Likes: 0
From: southwest michigan
An update. after plugging off the PVH system. the HVAC system now works normally. I can even let the truck sit for a while, then pull the vacuum lines from the reservoir and hear air hissing in, so everything after the check valve seems to be working.
The truck still is throwing the lean code occasionally though, and bogs when it is put into gear.
The truck still is throwing the lean code occasionally though, and bogs when it is put into gear.
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
Thread Starter
Forum
Replies
Last Post
falklandsx
1997 - 2006 Expedition & Navigator
18
Dec 18, 2022 04:35 PM