MAF sensor wiring problem??? now knock sensor?
 

I need some help. I have a 1997 f150 4.6l. Okay i got a new motor and tranny put in and its been running like terrible ever since. I got a diagnostic test done and it says P0201 which is low input to maf sensor. well i hooked up another sesnor and it still ran bad. i unplugged the battery and everything to reset the ecm. does this mean that the wiring is either broken or not plugged in?? The wiring is good down to the first plug in behind the fan and its plugged in there but thats the furthest i can see where the wiring goes...any help would be good where the wiring goes from there or any ideas of what to look at? thanks..

come on anyone have any ideas??? is there any type of fuse for it?? where is the final plug in for it at??

i dont know much bout the later model trucks engine wise but the old ones have a ground off the maf. could it be you are not getting a good ground??thats about the most common wirring problem and the easiest to track down.hope you get it!

What size motor was in it before you changed it?

do you know where the ground for it is?? the furthest i can see or feel the wiring go is like between the block and manifold i think? the motor was hot when i was trying to figure it out so i couldnt look at it to good because i started to burn my hand. it was a 4.6 and still is. spun a crank bearing at 156k miles

The MAF isn't grounded like you may be thinking. You have to do a PIN check where it plugs in at the cradle(Junction Box where the MEGA fuses are located) on the firewall behind the battery. Everything is grounded on the firewall (main ground)at that location. I can't recall exactly , but I think the MAF is PIN 71-72 (Im not in the shop)..

You need a diagram and need to test at the plug HOT , Test Continuity, Resistance instead of looking for simple ground.


Those wires you speak of between the block and manifold lead to other sensors - CHT Sensor and Knock Sensor, nothing to do with the problem..

I took my truck to a mechanic I know and he saw what was wrong in a few seconds...The company that put my motor in hooked my maf sensor into the knock sensor or cht sensor, he thinks its the knock or cht sensor anyways. So I switch that but now where does my knock sensor or cht sensor plug into? The mechanic who noticed it said he thought he can do it, that it just needs ran back to the back of the motor instead of the front where it is now. And it gets plugged in towards the back of the motor. Im just wondering if I'd be able to do this myself or if it would be hard to get to the plug?? Would this be the knock or cht sensor? All i can tell is thatt its coming out from in between the block and intake manifold. and it has a plastic plug on the end of it. Any help on what it is or where it plugs into exactly would be great...thanks

The knock sensor is on the block in the valley between the cylinder heads. the plug should be behind the engine between the passenger side cylinder head and the fire wall. It should have a push pin clip that is attached to the water pump heater hose pipe coming out of the back of the engine.

JMC

PS How in the H did they mix up the plugs?

Thats why im not sure if it is the knock sensor becasue the plug of it doesnt sound like it would go together with the maf sensor plug by the way you describe it...this plug that i dont know where it is goes that i think is the knock sensor is exactly like the plug the maf sensor really does plug into... but this comes out between the block and manifold..i dont know if thats where its suppsoed to come out at but thats where they have it...do you have any ideas of what other sensor plug is just like the one the maf goes too? but is down around the motor???

Pictures would help a lot. It is kind of difficult to figure it out without them.

JMC

Well i got it figured out it was the knock sensor...i had to tape it to a clothes hanger and fish it back through betweent he block and manifold all the way back to the firewall where it plugs in..took me about 2 hours..thansk for the help

Well , you got me confused lol - about the ground thing. Yeah , pics with an explanation would have helped . Glad you gotter fixed tho..:thumbsup:

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