Strange setup IAT on 4.9 F150
08-12-2010, 07:11 PM
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Strange setup IAT on 4.9 F150
Hey guys, figured Id ask a larger audience and see what I get. Im working on a 96 F150 with a 4.9 I6. Wont Smog cause of a MIL for the IAT signal high. Ok thats fine probably unplugged or has a damaged wire. Pop the hood and notice that YEP IAT is unplugged on the intake manifold, problem is no connector. I pulled the injector harness off and opened it up and still no wiring Odd. Start looking around and low and behold the sensors is in the top of the Airbox. Has the Gray and Gray/red wiring and the harness is setup like this stock as there is zero evidence the harness has ever been opened up (factory tape ect.)
I went on Mitchell1 OnDemand and looked over the diagrams and component locations for this motor including updating and backdating years thinking it may have been swapped at some point. According to the info there always has been an IAT sensor in the #1 intake runner just where this sensor is located.
Just to double check things I opened up the EEC harness from the EEC connector to the sqaure connector that bolts to the engine harness and there is no wire there or on the engine side leading me to believe this has always been like this.
The door vin tag and the dash vin match as does the hood sticker and the belt routing sticker saying its a 4.9 truck California emmisions. This will not pass a visual test from the trained monkeys at the Smog shop even if the MIL was off due to it being unplugged.
So I gotta ask can anyone think of a certain model that had a 4.9 and had an IAT sensor in the air cleaner? Reason I ask is that theres some paint numbers on the valve cover leading me to believe the motor has been changed at some point, possibly being a mismatch to the PCM harness (which will even bolt up to a V8 harness
)
The kid that owns it bought it as a lein sale and knows nothing of the history of the truck. If I can get to the bottom of this Ill have it working Aok but it really doesnt make any sense.
I went on Mitchell1 OnDemand and looked over the diagrams and component locations for this motor including updating and backdating years thinking it may have been swapped at some point. According to the info there always has been an IAT sensor in the #1 intake runner just where this sensor is located.
Just to double check things I opened up the EEC harness from the EEC connector to the sqaure connector that bolts to the engine harness and there is no wire there or on the engine side leading me to believe this has always been like this.
The door vin tag and the dash vin match as does the hood sticker and the belt routing sticker saying its a 4.9 truck California emmisions. This will not pass a visual test from the trained monkeys at the Smog shop even if the MIL was off due to it being unplugged.
So I gotta ask can anyone think of a certain model that had a 4.9 and had an IAT sensor in the air cleaner? Reason I ask is that theres some paint numbers on the valve cover leading me to believe the motor has been changed at some point, possibly being a mismatch to the PCM harness (which will even bolt up to a V8 harness
) The kid that owns it bought it as a lein sale and knows nothing of the history of the truck. If I can get to the bottom of this Ill have it working Aok but it really doesnt make any sense.
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