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Smoke test revealed vacuum leak from mysterious part??? (+p0171)


joshuatbird

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2002 explorer Sport trac
I have a vacuum leak in my 2002 ford explorer sport trac 2wd. It's throwing a p0171 cylinder 1 too lean. I'm new to mechanics. Like really, really new, but luckily I'm an extraordinarily fast learner. This is my second day with the truck. I bought it (as is šŸ˜’), and on the drive home the code kicked on. He must have cleared the code though, because it was obvious he was trying to troubleshoot the issue. He replaced like all the hoses, the air filter, fuel filter, fan etc... MAF looks new too. Radiator and housing too, not sure why... I do apreciate the free parts šŸ˜. It doesn't take a genious to figure out they were attempting to solve the P0171. Apparently it was done in haste on a guess to guess basis, probably not the most effective approach... Anyhow, he gave up on it, and I got this really nice truck with like zero body damage, 180k on odometer, for $1500. After troubleshooting different systems via information I gathered online yesterday, I began to suspect a vacuum leak. Using a design from youtube, I built a home made smoke machine for $12, and easily traced a bad leak to a specific part that is attached to a vacuum port on my intake manifold. The repair manual issued by ford calls it a "heated pcv fitting". Searches for this turn up empty on Auto Zone, O'Reillys, Napa etc. Here is the picture of the part in the manual:

20210112_024346.jpg


A Google search for (year/make/model +) heated pcv fitting turned up nothing like it. Searches for (year/make/model +) heated pcv intake fitting turned up the part below. It does look similar, but when I go to checkout, the site says it doesn't fit my vehicle. I found many similar parts using this search term, all of them with slight variants for different trucks, but nothing that says it fits this vehicle. This is becoming quite a headache šŸ˜‘. Any insight would be greatly appreciated. I need to have it road ready by March 14th. Sorry if I'm calling things by the wrong name. I didn't know what a MAF sensor or an intake manifold or a p0171 was on Monday, like I said, very new to mechanics. Here is the picture of what the search that included the word "intake" first turned up:

20210112_035708.jpg
 


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1sicbronconut

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Is it the fitting or the hose that's attached to it? I've replaced a lot of those hoses over the years but never the fitting it's self, if it is the fitting a Ford dealership should be able to help you with it.
 




joshuatbird

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Is it the fitting or the hose that's attached to it? I've replaced a lot of those hoses over the years but never the fitting it's self, if it is the fitting a Ford dealership should be able to help you with it.
That little blue rubber gasket on the fitting(in the picture I posted) is toast.
 




DILLARD000

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@joshuatbird
OBD2 ToubleCode P0171 = Bank1 Too Lean
Yes, also had trouble finding FordMotorCraft part number for this "PCV Heated Fitting".
I've call it the "PCV Coolant Loop Heat Exchanger"; not so sure that's the "correct" name either.
It's simular to FordMotorCraft# 1L3z-6a666-aa\ev256, but has an open inner tube for vacuum without a PCV Valve like on F150s;
so it seems to be unique for the IntakeManifold & PCV system on 2000~2011 Ford V6~4.0L~SOHC engines.
Possibly could drill out inner valve from a new ev256, to replace this part, if outer diameter is the same?
If you suspect a vacuum leak, smear a little RTV around that ORing or replace with new ORing.
I'm more suspect of the PCV Vacuum Tube+Elbows; the Elbows are notorious for cracks\leaks.

Original "PCV Coolant Loop Heat Exchanger" on right side of IntakeManifold throat,
with 5/16" Coolant Hose Barbs attached,
with 5/8" Vacuum Tube+Elbow assembly attached.
2001.Ford.ExST_Engi.AirN_PCVf.Xchg_Ford.ev256_OldInst.GIF


Modified "PCV Coolant Loop Heat Exchanger" with Coolant 5/16"HoseBarbs ground off;
did this when I deleted the entire PCV Coolant 5/16"Loop.
ORing can be supplemented with a smear of RTVSealant or replaced with new ORing.
2001.Ford.ExST_Engi.AirN_PCVh.Xchg_Ford.ev256_Modific.GIF


Modified "PCV Coolant Loop Heat Exchanger" re-installed in right side of IntakeManifold with RTV on ORing.
2001.Ford.ExST_Engi.AirN_PCVi.Xchg_Ford.ev256_NewInSt.GIF


Modifed "PCV Coolant Loop Heat Exchanger" re-installed with vacuum tube+elbows assembly re-attached.
Check these vacuum elbows & tube for cracks\leaks; a notorious cause of TroubleCode P0171.
2001.Ford.ExST_Engi.AirN_PCVj.Xchg_Ford.ev256_NewInSt.GIF


PCV Vacuum 5/8"ID Tube+Elbow assembly FordMotorCraft# 4L5z-6758-ha\kcv190
runs PCV Valve at rear of left ValveCover to "PCV Coolant Loop Heat Exchanger" on right of IntakeManifold throat.
2001.Ford.ExST_Engi.AirN_PCVm.Hose_Ford.kcv190_OldInst.GIF


PCV Valve FordMotorCraft# 2L5z-6a666-ba\ev268 with PCV Coolant Loop 5/16" OxBow+Hoses installed.
2001.Ford.ExST_Engi.AirN_PCVb.Valv_Ford.ev268.JPG


PCV Valve FordMotorCraft# 2L5z-6a666-ba\ev268 with PCV Coolant Loop 5/16" OxBow+Hoses deleted.
2001.Ford.ExST_Engi.AirN_PCVc.Valv_Ford.ev268.JPG


PCV Valve FordMotorCraft# 2L5z-6a666-ba\ev268 with PCV Coolant Loop 5/16" OxBow.
If deleting entire PCV Coolant 5/16" Loop, this OxBow can be easily removed from PCV Valve.
2001.Ford.ExST_Engi.AirN_PCVa.Valv_Ford.ev268.JPG
 




joshuatbird

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Year, Model & Trim Level
2002 explorer Sport trac
@joshuatbird
OBD2 ToubleCode P0171 = Bank1 Too Lean
Yes, also had trouble finding FordMotorCraft part number for this "PCV Heated Fitting".
I've call it the "PCV Coolant Loop Heat Exchanger"; not so sure that's the "correct" name either.
It's simular to FordMotorCraft# 1L3z-6a666-aa\ev256, but has an open inner tube for vacuum without a PCV Valve like on F150s;
so it seems to be unique for the IntakeManifold & PCV system on 2000~2011 Ford V6~4.0L~SOHC engines.
Possibly could drill out inner valve from a new ev256, to replace this part, if outer diameter is the same?
If you suspect a vacuum leak, smear a little RTV around that ORing or replace with new ORing.
I'm more suspect of the PCV Vacuum Tube+Elbows; the Elbows are notorious for cracks\leaks.

Original "PCV Coolant Loop Heat Exchanger" on right side of IntakeManifold throat,
with 5/16" Coolant Hose Barbs attached,
with 5/8" Vacuum Tube+Elbow assembly attached.
View attachment 326579

Modified "PCV Coolant Loop Heat Exchanger" with Coolant 5/16"HoseBarbs ground off;
did this when I deleted the entire PCV Coolant 5/16"Loop.
ORing can be supplemented with a smear of RTVSealant or replaced with new ORing.
View attachment 326580

Modified "PCV Coolant Loop Heat Exchanger" re-installed in right side of IntakeManifold with RTV on ORing.
View attachment 326581

Modifed "PCV Coolant Loop Heat Exchanger" re-installed with vacuum tube+elbows assembly re-attached.
Check these vacuum elbows & tube for cracks\leaks; a notorious cause of TroubleCode P0171.
View attachment 326582

PCV Vacuum 5/8"ID Tube+Elbow assembly FordMotorCraft# 4L5z-6758-ha\kcv190
runs PCV Valve at rear of left ValveCover to "PCV Coolant Loop Heat Exchanger" on right of IntakeManifold throat.
View attachment 326583

PCV Valve FordMotorCraft# 2L5z-6a666-ba\ev268 with PCV Coolant Loop 5/16" OxBow+Hoses installed.
View attachment 326584

PCV Valve FordMotorCraft# 2L5z-6a666-ba\ev268 with PCV Coolant Loop 5/16" OxBow+Hoses deleted.
View attachment 326585

PCV Valve FordMotorCraft# 2L5z-6a666-ba\ev268 with PCV Coolant Loop 5/16" OxBow.
If deleting entire PCV Coolant 5/16" Loop, this OxBow can be easily removed from PCV Valve.
View attachment 326586
Nice mod work, and thank you very much for the reply. As happy as I am to know that I'm not alone in failing to find the replacement part, It also sucks pretty bad that it will likely require a mod. I do have what I need to mod it like you did, but I'm nervous about removing the coolant loop from the system. Does it run well when applied this way? For now I think I'll try to source the o ring and hit it with the rtv sealant if you think it will hold in that application. The air leak happens between the o-ring around the inner chamber as indicated by the blue arrow. I just snatched your pic to demonstrate the location šŸ˜.

iMarkup_20210113_110923.jpg
 




DILLARD000

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Unless your ORing is severely damaged, RTV should fix it. If not then pick up a new ORing at your nearest parts house. I've been running without the PCV Coolant Loop for about a year now without issue. Initially got rid of it after a coolant leak on both the plastic HeaterControlValve & the plastic Tee that feeds it, then realized that coolant flows thru this side loop only if cab heat is on; usually dont turn on cab heat until several minutes after start.
 




DILLARD000

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Only place I've seen "PCV Coolant Loop Heat Exchanger" for sale is on Ebay with an entire used IntakeManifold assembly.
2001.Ford.ExST_Engi.AirN_PCVf.Xchg_Ford.ev256_Oldc.GIF


This FordMotorCraft# 1L5e-18696-bc\s70da steel hose fitting assembly bolted to right side of Engine\ValveCover
is one end of factory PCV Coolant Loop: 5/8"HoseThru from HeaterCore & 5/8x5/16x5/8"HoseTee to HeaterCore+PCVCoolantLoop.
If deleting PCV Coolant Loop, delete this & plastic 5/8x5/16x5/8"HoseTeeFitting FordMotorCraft# 1L5z-18472-ad near FireWall.
2001.Ford.ExST_Engi.AirN_PCVx.HosT_Ford.1L5e-18696-bc=s70da_Dlet.GIF
2001.Ford.ExST_Engi.AirN_PCVx.HosT_Ford.1L5z-18472-ad_Dlet.gif


While deleting the PCV Coolant Loop, I also replaced the VacuumToClose HeaterControlValve
leaky plastic BallType FordMotorCraft# yg368 with metal PlugType 4SeasonsFactoryAir# 74603,
& relocated it from under Alternator to up near FireWall in HeaterCoreCoolantLoop.
2001.Ford.ExST_Engi.Cool_Heat.Valv_Norm=Open_Ford.yg368.GIF
2001.Ford.ExST_Engi.Cool_Heat.Valv_Norm=Open_4Seasons.74603.GIF
 




DILLARD000

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Suppose if doing full proper delete of PCV Coolant Loop, could install newer version PCV Valve with ElectricHeat;
would likely need TimeDelayOff relay; PCV Valve heater on with starter relay, off 1~2 minutes later.
FordMotorCraft# 3f2z-6a666-aa
2001.Ford.ExST_Engi.AirN_PCVd.Valv_Ford.3f2z-6a666-aa_ElecHeat.GIF
 




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