Can't get rid of P0171 (Lean on Bank 1) on Ford5.4 in E350

[Brad J]

Memorial Day Weekend we bought a $600 wrecked 2001 Ford E350 (244k miles) for 9 of us and 2 dogs to go to the CA & OR coasts. A one week rental was $2,500 so I figured why waste the money on a rental. The frame was fine but the whole front end sheet metal was pushed back 1-2". We had 7 weeks to get it fixed before our trip and I only had Fridays and Saturday's to get it done. We found a donor cab for $200 & after it was installed the engine would die in 3 seconds. We found the accident had damaged the wiring harness due to the Cam position Sensor not picking up. Swapped out the whole under hood harness and it now ran but kept getting P0171 (Lean on Bank 1) sometimes joined with a P0174 (Lean on Bank 2). We got Temp Tags and had a successful trip in the middle of July except for one day it ran really rough with Misfire codes (P0300, 302 & 305) but it went away.

Since we got home I have been trying to get rid of the reoccurring P0171 to get it Registered. I have run a smoke machine on the Airbox intake, PCV hose & Brake Booster Hose but I am not finding a leak. I have sprayed soapy water around all Hoses on the top of the engine and Propane as well but still can't find any leaks. I have replaced the Mass Air Flow Sensor, Fuel Pump, Fuel Filter, PCV Valve, All 3 02 Sensors, Spark Plugs, Coil Packs, Intake Manifold Gasket, Throttle Body Gasket. I've watched a ton of YouTube videos and searched but I am stuck. Is there something that I am missing?

Thanks, Brad

 

[Brad J]

My short term Fuel Trims on banks 1 and 2 are around 20% but drop with high RPM. From the YouTube videos this would be a vacuum leak but I can't seem to find it. I plugged the Hose to the Brake Power Booster but that didn't make a change.


At Idle


At 2500 RPM

 

[ID Bronco]

Wow, I would NEVER attempt this but good for you for finding a way to have a great trip. That's alot of work in a few weekends.

 

[shortstraw8]

I am troubleshooting the same p0107 issue on my nephews 99 buick 3.1 he got for free for his first car. I replaced the map and maf sensors pcv valve/tube and air intake to valve cover tube as a start, now trying to track down a smoke machine for a better check. Are fuel pump/filter and spark plugs coil packs something that usually resolves this code? Starting to think it is a gasket like you have replaced, interested to see what other thoughts show up here.

 

[Brad J]

Thanks. I have an account for https://www.prodemand.com/ and it will break down the list of usual causes and the parts that Mechanics report replacing that fixes the code for most specific vehicles and this is what it pulled for my van. I did the 02 Sensors, Fuel Filter and Fuel Pump when I originally started it and had it die. The Fuel Pressure would start out at 10 then creep up to 40. When those didn't fix the issue I found a code pointing to the Cam Position Sensor. Swapped it out for a spare that I had but it didn't make a change and I had a hard time tracing its wires in the harness. The main harness runs right where most of the damage from the accident occurred. I did new Sparkplugs due to the miles and misfires on the trip. I noticed that most of the Coils were leaking and the wires were rusted so I replaced them as well.


Avenue of the Giants in CA

Airbnb in Florence OR on Heceta Beach

 

[TRD270]

Not much help but I couldn't get a misfire to clear on my 5.4. Replaced Coil, plug and injector. Still getting misfire, checked compression was fine. Someone on here suggested disconnecting battery for awhile. I left it off for a few days, was overkill but didn't need to drive it.

......never got the code again. Hope yours is as simple

 

[SnwMnkys]

Leaking exhaust before the 02 sensors will cause high fuel trims. Check your manifolds, gaskets, pin holes around the o2 bungs, etc.

 

[Brad J]

Leaking exhaust before the 02 sensors will cause high fuel trims. Check your manifolds, gaskets, pin holes around the o2 bungs, etc.

Thank you! It looks like this is it! I hooked up a Wet Dry Vac to the Tail pipe blowing in and sprayed soapy water on the exhaust manifold and both were blowing huge bubbles on the rear cylinders. I noticed that one of the studs was broke off for one of them. The 02 sensors also had a little air coming out of them as well. I got both manifolds off but 2 studs are broke below the surface of the head. One is on cylinder one (Passenger side) right behind the Shock Tower so it is not going to be easy. I ordered a drill out and extractor tool but there may not be enough room for it to fit in there. At least I finally know where the leak was coming from I should have also stated that I have no clue what I am looking at as far as numbers on the Scan Tool and what to look for. I have been learning a lot from ScannerDanner on YouTube.

 

[Brad J]

I am troubleshooting the same p0107 issue on my nephews 99 buick 3.1 he got for free for his first car. I replaced the map and maf sensors pcv valve/tube and air intake to valve cover tube as a start, now trying to track down a smoke machine for a better check. Are fuel pump/filter and spark plugs coil packs something that usually resolves this code? Starting to think it is a gasket like you have replaced, interested to see what other thoughts show up here.

You are welcome to borrow the Smoke Machine that I made. There are some good YouTube videos on how to make them. I used an old Soldering Iron and an old Fuel rail for a metal schrader valve and a fitting to push different size hoses onto.

 

[shortstraw8]

I will probably build one, I have enough supplies laying around to do so, thanks though! The plus side is the codes may have cleared and currently staying clear. My nephew is going to come over this weekend and we are going to do some basic maintenance, gap plugs, flush coolant, oil change, run through the brakes and then drive it around.

 

[Brad J]

I forgot to post an update to this. I replaced the Intake Manifold Gasket and found that it was leaking at the Exhaust Manifolds with several Studs broken off. Removed the broken studs with the worst one being broke inside of the Head with nothing sticking out and right behind the shock tower. New Exhaust Manifolds and Gaskets but still kept getting the same codes. Found that the new Brake Booster was leaking at the Vacuum Hose fitting. I tried Silicone and that didn't hold for long. Someone told me to try thick bearing Grease and that did the trick. No more codes and worked perfect for our trip to Durango Colorado, Mesa Verde, Hovenweep & Natural Bridges during the summer.