Bad MAF sensor
Thread Starter
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Mountain Pass
Joined: May 2019
Posts: 204
Likes: 10
I was thinking the same thing. I ended up using a gauge from the parts store. I don't think it's a fuel issue though. I have not replaced the front tank and sending unit yet. Could it be the Tps?
Lead Driver
Joined: Jan 2019
Posts: 5,081
Likes: 865
From: N.W. Alabama
how to test TPS, really need to make sure what your fuel pressure is
Fuel Injection Technical Library » Throttle Position Sensor (TPS)
Fuel Injection Technical Library » Throttle Position Sensor (TPS)
Thread Starter
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Mountain Pass
Joined: May 2019
Posts: 204
Likes: 10
Ill test it tomorrow. Need to go to another parts store to try another gauge. They only had the one. It was a free truck so I don't mind putting money into it but I would like to get it fixed.
Lead Driver
Joined: Jan 2019
Posts: 5,081
Likes: 865
From: N.W. Alabama
you changed the regulator, the other day, I wonder how bad dirty your fuel filter is, that you changed a year ago, with gauge hooked up and you turn key to on position, what does it read, should be mid 30's, and when truck is running and you blip throttle, the pressure should go up(hi 30's to lo 40's) then settle back down, pressure should idle at lo to mid 30's
Thread Starter
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Mountain Pass
Joined: May 2019
Posts: 204
Likes: 10
The pressure goes down from 20 to 18 when i hit the throttle. I think I am going to put a new fuel filter on. Cheap and easy. I am starting to wonder if there was crap in the return line and it went in the tank. Ill start with the filter and maybe drop the tank to check the sock on the pump,.
Thread Starter
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Mountain Pass
Joined: May 2019
Posts: 204
Likes: 10
Fuel filter did not fix it. Still will not run with MAF hooked up. Throttle response in park is not bad, but barely runs when driving. My only other thought is mud daubers maybe plugging the vent on the tank. This truck had them everywhere when I got it and I still see some nests along with wasps. Either way I need to pull the tank.
Lead Driver
Joined: Jan 2019
Posts: 5,081
Likes: 865
From: N.W. Alabama
you still need to test the MAF connector that runs into the wire loom and see if it has issues of any type
Part 1 -How to Test the Ford Mass Air Flow (MAF) Sensor
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Thread Starter
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Mountain Pass
Joined: May 2019
Posts: 204
Likes: 10
I decided to replace the front tank and sending unit instead of pulling the rear tank(It would not run on the front tank). It starts and runs now but has the same issue when air is flowing through MAF.
Thread Starter
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Mountain Pass
Joined: May 2019
Posts: 204
Likes: 10
Tested the MAF. No issues. Truck will idle without inlet tube installed on MAF. No codes at all. Two new fuel pumps. Will not stay running with MAF installed in tube. Is there anyone that can help? Otherwise I am selling this thing for whatever I can get for it.
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Mountain Pass
Joined: May 2019
Posts: 204
Likes: 10
Also, if the electrical connection to the MAF is unplugged and hooked up to the intake tube the truck runs. It will rev up in park and will accelerate poorly while driving. Still no check engine light when unplugged though.
Moderator
Joined: Jun 2003
Posts: 3,549
Likes: 71
From: Calhoun GA
When the MAF harness is unplugged from the meter, the ECU resorts to a "Failed MAF Fuel" table...meaning it will run the truck, but now well. Is there any way you can borrow/rent a scan tool that will display live engine data?