iat sensor question - Fuel Economy, Hypermiling, EcoModding News and Forum

hillbilly83 · 07-06-2015, 01:32 PM

I have a 2003 Chrysler t&c with the 3.8. I recently read somewhere else about unplugging the iat and putting a resistor in instead, the theory behind it made sense so I tried it. I put a 5.6k in. the check engine light came on and after about 35 miles the light went off. Initially I thought I was getting better mileage based on my factory overhead mileage avg reading, but I wasnt sure so I took out the resistor and plugged the iat sensor back in. Now my check engine light came on and hasnt turned off. Should I be concerned, should I put the resistor back in? any ideas?

dirtydave · 07-06-2015, 04:28 PM

how did it change the car?

hillbilly83 · 07-06-2015, 08:33 PM

Well I put the resistor back in and the check engine light turned off and my mpg avg went up as well. Any negative long term effects from mortifying the iat

ksa8907 · 07-06-2015, 10:17 PM

It is very unlikely to make a real difference in mileage because the iat is only a part of a bigger system, the computer relies more heavily on the o2 sensors. Pop the resistor out and the cel should reset after 3 normal run cycles.

roosterk0031 · 07-06-2015, 10:30 PM

Tweak any signal but the O2 sensor and it will compensate pretty quickly. Tell the MAF there less air coming thru the O2 sensor will figure it out and fix it to maintain Stoinch, except when running closed loop, but even then the LTFR will compensate some what so still not going to fake it out go run lean.

California98Civic · 07-06-2015, 10:46 PM

Don't measure MPG using the OEM electronic fauges since you have modified data inputs fornthe ECU. Use the pump and mileage. I don't think you can be sure the benefit has been real, or as large as you think, based on the OEM gauge alone.

oil pan 4 · 07-07-2015, 12:45 AM

Quote:

Originally Posted by hillbilly83

Any negative long term effects from mortifying the iat

In 1999 I had a 80s V6 fuel injected Camaro that had a malfunctioning IAT. The IAT was telling the computer the air was a lot hotter than it actually was, for some reason that leaned out the air fuel mixture, it ran lean and burned all the exhaust valves.

hillbilly83 · 07-07-2015, 05:02 AM

Before,the mod my gauges avg stayed at 22.8 mpg, and that coincided with mileage and the pump pretty close within .2 so now the gauge avg is 25.4. Maybe a placebo effect, am I driving better? Idk. If this is the case how do we fool the o2 and maf? I also modified my airbox, cut a slot in the resonator part allowing air to come under my hood straight into the airbox, pre filter of course

California98Civic · 07-07-2015, 11:04 AM

Quote:

Originally Posted by hillbilly83

Before,the mod my gauges avg stayed at 22.8 mpg, and that coincided with mileage and the pump pretty close within .2 so now the gauge avg is 25.4. Maybe a placebo effect, am I driving better? Idk. If this is the case how do we fool the o2 and maf? I also modified my airbox, cut a slot in the resonator part allowing air to come under my hood straight into the airbox, pre filter of course

Trying to fool the electronics is one of the more difficult ways to get higher MPG. Every electronic sensor signal mod has other consequences in the engine management system. You want to be careful with your car and safety. There is much easier to reach "low hanging fruit" ... take a look at this list (have you already?): 65+ Vehicle modifications for better fuel economy - EcoModder.com

And the hypermiling tips too: 100+ Hypermiling / ecodriving tips & tactics for better mpg - EcoModder.com

hillbilly83 · 07-07-2015, 11:53 AM

Would warm air intake do the same thing as what I want the resistor to do? Are there any programmers that work for fe? I just think covering up things reducing drag isnt going to do a whole lot, or will it?