delete this friggen thread. thanks mods.
Resistor mod
99Dakota
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x2:wave:
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I've read here and on other forums the iat relocation trick is garbage, but this is the first i have seen on wiring in a resistor. I'm actually skeptical, but for a buck it is worth a shot.
I fully agree the relocation trick is garbage. AIRRAM sells a wiring harness for this trick with a resistor in it marketed as the Power Wire. It's $60 for those who don't want to spend a $1 and some time on it.
FWIW: I think this trick is a complete waste of time for anyone who has a programmer or a flash that has real tuning abilities to it (SCT, Diablo, etc.), but if it works for people without those, then go for it.
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did a similar trick like this on my 99 ranger. could feel a slight difference in power but never actually dynoed it.
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The IAT sensor is on the front top left of the intake manifold on 3.9 5.2 and 5.9s.
See the threaded hole to the right of the fuel rail mounting bolt, this is your sensor. I have always heard it is a waste, but if it works for you awesome.
![Image]()
See the threaded hole to the right of the fuel rail mounting bolt, this is your sensor. I have always heard it is a waste, but if it works for you awesome.
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They sell the resistors on ebay and have for years.
I put the resistor on my 1992 Magnum Dakota long ago just to take it back out and throw in the trash.
This diode tricks the fuel injection to think the outside air temperature is colder than it actually is. The result is incresed fuel consumption and cylinder wash. My truck lost about 1 mpg and ran way rich.
I would not recommend this mod to anyone. There is a reason the engine needs accurate ambient air temps!! Pursue your power increase with a tuner or other bolt ons.
I put the resistor on my 1992 Magnum Dakota long ago just to take it back out and throw in the trash.
This diode tricks the fuel injection to think the outside air temperature is colder than it actually is. The result is incresed fuel consumption and cylinder wash. My truck lost about 1 mpg and ran way rich.
I would not recommend this mod to anyone. There is a reason the engine needs accurate ambient air temps!! Pursue your power increase with a tuner or other bolt ons.
maybe for the size u bought. eitherway, this resistor does NOT control fuel only advance the timing if you cool the temps. the o2's control fuel trim. sounds like you have other issues. either that or it works differently on pre obd2 system.
try it on anyone of your newer trucks, bet you will see a different in mpg and power. the other guy at work with has an 07 ram hemi and has this done and is getting 16.5mpg compared to his steady 13.6mpg no matter how he drove. i beleive he is running a 22k ohm resistor though, which i couldnt find at my local radioshack.
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That resistor can't do what the MSD does. The MSD only adjusts spark advance and it does it in an adjustable, accurate fashion. The resistor mod is a hack job mod that gives you an uncontrollable amount of spark advance as well as screwing up the afr calculation.hmm. how much did that MSD thing cost compared to a 99 cent resistor that could do about the samething your describing?
And did I read it right that you did this on top of the superchips tune? So you are taking an ecm that is already advancing spark enough to require 93 octane and now advancing it more? Just wait until it gets hot out and your fuel trims catch up and lean that mixture back out.
The PCM does reference the IAT sensor voltage for control of the fuel just so you know.
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I usually don't get involved in these hack job bullshit threads, but you are spending WAY too much time spreading wrong information. Let's pick apart your post bit by bit.
You say that like there is a science behind picking the resistance to fool the computer. Here is the problem with your logic. The IAT is a negative temperature coefficient sensor. You are correct that more resistance makes the PCM think it is sucking in cooler air, but the problem is that this is not linear. As The resistance changes very rapidly when it is cold, but as it comes up to running temp there is very little change in the resistance. Having a resistor that large is basically telling it is's sucking ice cold air all the time. Also, the colder it is outside, the colder it's going to tell the PCM it is. It may be fine when it's warm outside, but the extra resistance PLUS the resistor may very well toss a code and turn your check engine light on. You don't say a word about actually looking this stuff up, so I'll assume you're taking a complete random stab at this "22 thousand ohms" that you're preaching. Take a look at a generic NTC resistor graph if you want to see what I am talking about. http://www.designinfo.com/cornerstone/ref/graphntc.gif
Sort of. The PCM takes this into account when setting the timing, but it's watching the knock sensor A LOT more closely. As a rule of thumb, most companies are trying to run as much timing as they can without the engine detonating. The knock sensor detects this, not the IAT. Yeah, the PCM looks at air temp, thinks it's getting more oxygen than usual, and may try to bump the timing forward a degree or two, but the knock sensor is going to stop it if it goes too far. This is part of the on the fly control that you keep talking about. Speaking of closed loop....
This is partially correct. When the engine is in closed loop the engine uses o2 sensors, along with other inputs, to control fuel trim. the o2 sensors are NOT the sole input the PCM uses to control fuel trim. Don't believe me? Try slowing down without the PCM using the throttle position sensor to know you're not giving it gas
Also, in open loop, the O2 sensors are completely useless. The computer is only guessing what the parameters should be based on things like the air temp, TPS signal, BARO, MAP, etc. Throwing your IAT out of wack just made your PCM guess wrong!All that being said, if you guys want to start hacking your wiring, be my guest. Maybe you'll be lucky... maybe you won't. Me, I feel like Dodge spent millions of dollars writing this programming for a reason. If "an extra 3 degrees timing" really did all these great things with absolutely no ill effects, don't you think that Dodge would have put that programming in their selves?
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Just for you lazy asses... Here is the 22k ohm 1/2 watt resistor. Here is also a link to them on Ebay. 50 of them for 1.50 so if they work you can mod all your friends cars.... If not then you have 50 to make a necklace out of.
http://cgi.ebay.com/22K-Ohm-1-2-Wat...tors-50pcs-/260451731656?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3ca42208c8
![Image]()
http://cgi.ebay.com/22K-Ohm-1-2-Wat...tors-50pcs-/260451731656?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3ca42208c8
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Cutting the wires was a mistake IMO. I used to just bend the resistor into a U and plug it into the harness.
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