Ford E-350 Econoline Van Check Engine Light with P0171 and P0174 System Too lean Codes Diag and Fix

I picked up this 1996 Ford E-350 Van super cheap but it had a lot of issues. The poor van Had been neglected and sat for about a year and a half as it sustained some vandalism. I was able to get it home and install a new Cat before emissions testing So I could get the title transferred to my name. Fortunately, it passed the emissions test just fine but on the way home the check engine light came on. I read the codes and Got P0171 and P0174. I thought this would be a great opportunity to improve my diagnostic skills and get better as a mechanic. I was able to use the long-term fuel trim data read out and graphed on my scan tool to lead me in the right direction to what the problem is. This leads me to a fuel issue so I look into my Fuel pressure and MAF sensor. The mass air flow sensor is quite dirty so I cleaned it, however, this did not solve my issue. I finally found it to be a fuel pressure issue because a small drop in pressure could be seen during acceleration on the fuel pressure test. I decided to replace the Fuel pump and filter based on the findings and the vehicle history. The pump looked very old and the pickup socks were extremely dirty. I also found a wiring issue that could have contributed to the fuel pressure drop due to a hidden excessive voltage drop on the ground circuit for the pump. Once everything was Repaired I drove it for over 50 miles and come back to take a look at my long-term fuel trims to confirm the fix. I hope this video was helpful and thanks for watching!

Disclaimer: work on and modify a vehicle at your own risk. You are solely responsible for your actions. Always use proper safety equipment for the job

Note: This van Has OBD2 (the first year it was required in the USA): The scanner I used only works on obd2 vehicles (1996 or later except for a small subset of 94 and 95-year vehicles)

Find the Diagnostic Equipment I used in the video here:
LAUNCH CRP123E OBD2 Scanner (Scan tool used in the video): https://amzn.to/3FCZ7b9 (paid link)
Mucar CDEE900 (Best value scan tool I have tested): https://ebay.us/LXOYDs (paid link)
MUCAR CDL20 OBD2 Code Reader (cheapest Scan tool I found with live Graphing!) https://ebay.us/ypHjXw (paid link)
Fuel Injector Injection Pump Pressure Tester Gauge Kit (master set): https://amzn.to/3LCAxv3 (paid link)
RC Mass Air Flow Sensor Cleaner: https://amzn.to/40seqvk (paid link)
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4WheelKid
P.O. box 286
Sedalia, CO 80135

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