If it ain't Broke, don't FIX IT!!!

[RCone]

Ok, so I decide to relocate my IAT to the airbox. I do, start truck up, everything a OK. Run errand, shut down truck for 10 minutes, restart and temperature gauge spikes to 240 degress and check gauges light comes on. Obviously, truck temperature WAS NOT 240 degrees. Also threw a P0116 code. Hmmm, get home, disconnect batteries, pull IAT from airbox and tape to top of airbox, same thing. Pull harness and check for continuity, no problem there. Checked resistance values of new IAT at 74 deg F and reads bout 12 ohms (right where it should be at that temperature). Checked all pins on harness and truck. Ok there. Take out old IAT (stock location), clean with carbruetor cleaner (yes, it was pretty dirty) reinstall and hooked up at stock location. PROBLEM GONE! WTF???? Anyone got an ideas on this one? BTW, running a 180 degree thermostat. Hoping that Marco reads this and weighs in with an opinion as I am stumped.



BTW, driveability became an issue when check gauges lite came on. Computer didn't like it one bit. Shift points messed up, poor acceleration and everything. Almost like limp mode.



Roger

 

[Mundgyver]

I think your problem would be that the airbox is plastic and that the stock location for the IAT is metal. I'm thinking a ground path here for the circuit and its operation. You might think about putting it in the intake air horn up around the dip stick mount. I think that this has been done by others with some success. One other thing to think about also is the wiring. If you did a wire extension, the type of wire might play in here. I'm talking about the material of the wire. Thermocouple wiring is generally made out of two different alloys. I'm not sure if this is the case with the IAT or not. If you extended the wiring and just used regular wire and the harness has a special alloy wire, that might also be a problem. Good luck.

 

[dresslered]

IAT resisance?

Checked resistance values of new IAT at 74 deg F and reads bout 12 ohms

I believe that the IAT sensor should be about 9k to 11kohms at 77-degrees. Perhaps you just left off the 'k' but thought that I might mention it in case you had a short.



It shouldn't mater what the IAT is mounted in (i. e. plastic) as it is a two-contact sensor. I'm not sure that I would bother moving it in the first place, however.



P. S.



CAV CIRCUIT FUNCTION

A K104 18BK/LB B(+)

B K21 18BK/RD INTAKE AIR TEMP SENSOR SIGNAL

 

[RCone]

Yes, I did leave off the "K" on the 12K ohms. Thank you for the responses. I think I learned my lesson David with regard to the topic of this thread. You are right, why move it? But, having said that, will I ever learn? I wasn't looking for a power increase nor improved mileage. I only thought to move it as I do have an exhaust brake and apparently it causes it to carbon up much quicker and it would be much easier to get at from a maintenance standpoint. Me thinks I will not tempt fate again, leastways in that area. Will I continue to mess with my truck? Yup. Seems as though human nature is never totally satisfied.



Roger



PS. I still can't help but wonder tho what caused it to act up. I just have a need to know.

 

[Mundgyver]

Will I continue to mess with my truck?

Its not messing with the truck Your just tweaking it's hidden potential, through selective experimentation based on well reasoned and an analytically sophisticated thought process



That sound better

 

[dresslered]

Roger-

I'd be real curious as to what your problem was if you find out. I too had read all the discussions regarding the IAT, and since I have an exhaust brake, I felt inclined to investigate as well. What I found was a very dirty sensor. My first thought was that this contamination was causing a parallel resistance path thus lowering the total resistance. I measured mine before and after cleaning with absolutely no change noted. In fact, I'm not even going to check mine anymore. Yes, I believe people have had faulty sensors, but no, I don't think that it is a real problem. But, that is just my opinion. Don't ever feel bad about making improvements on your truck. You are just going through some of the R&D efforts at this time.