Albuquerque Jim

Resistor Mod

What is this really?

I am not a total idiot when it comes to trucks, but I haven't spent any time with piggy back computers and such yet.

Can someone fill me in on the validity of this mod?

Yoter

Never heard of this mod on any vehicle. It seems fishy that under tools needed it states only a "piece" of electrical tape and yourself. No wire cutters, wire connectors, soldering iron ect ect.........? How so? I think there is something off here. And only for $4? Hmmm, im gonna pass and spend that $4 on some decal kit that will make me go faster. By the way that decal remark is a joke. I felt I better say joke so I dont get someone asking "how do decals make you go faster"? (Rant Mode Off)

turboale

Looks too good to be true to mee too...

szf2

Never heard of that before. Did some research and it looks like IAT Sensor = Intake Air Temperature Sensor. So the resistor must decrease some signal from the AFM or MAF. Maybe this makes the ECU think the air coming in is colder than it really is and the ECU responds with more fuel? Just guessing really. Maybe someone who knows more about the functioning of the ECU will chime in.

WT

Think this might answer a few questions. I think a few people here have done this mod.
http://www.midiwall.com/4Runner/ect.html

MTL_4runner

All you are doing with the mod is adjusting the output from one of the sensors.
It does work but I doubt 15 HP worth.
May help get rid of a pinging condition (due to leanout) if you have one.

Yoter

I like Dr. Zs info on this & will seriously look into his over the EBay ad. The ad states that you only need a piece of electrical tape (LOL), no tools,no wire,no conectors,no soldering eq.,and one I am wondering about being no damage to your eng.. If it alters your timing and allows more fuel to be delivered couldnt that overload the fuel injectors? This EBay ad may have stole the idea from someone not saying they did but it lacks the proper info on the mod. Dr. Z goes above and beyond explaining it all. Maybe that a deal on the resistor but the facts are not there for me to believe.

MTL_4runner

You should really have a potentiometer (like Dr Z suggests) rather than a single resistor. You are trying to fine tune the output of the sensor for best performance and I guarantee a single resistor won't work unless you get VERY lucky.

ALBPM

I agree!!!!

Better consult with the Dr. first.

rimpainter.com

Is there a Dr in the house?

Where you at Galen?

Dr. Zhivago

I'm here.

As for modding the IAT on our trucks: On some vehicles, changing the IAT does make a big enough difference to warrant messing around with it. What the resistor does is fool the ECU into thinking the Intake Air is cooler than it is, by increasing the circuit resistance, which can affect timing advance and fuel enrichment.

However, it does NOTHING for performance on the 5VZ-FE. I am speaking from experience. I had done the IAT mod on my truck with a 10K Ohm Potentiometer to see if there was any performance to be gained from it. There wasn't. Using my BR-2, I analyzed the Timing and Fuel Trim curves and there are no changes made to either of these parameters when modifying the IAT sensor circuit. With a 10K Ohm pot on these engines, you can bring the "Perceived" IAT down to 5 Degrees F, so you can be assured that I tested the full gamut of temperature ranges.

On the other hand, the ECT mod does improve low end and midrange torque and responsiveness. Mind, you it's not an earth-shattering difference, but it is noticeable. WOT is affected as well, but not to a great extent as the WOT maps are pretty set and fairly rich on a NA engine. You need a piggy-back to mess with those so that performance is noticeably affected.

All those E-Bay ads assume one resistor value for ALL cars wil suffice. That's BS. I hope this clears things up.

Peace!
G

MTL_4runner

I am not surprised, seems like the best you could do is to just richen the mixture and maybe eliminate any lean spots in the curve......I wouldn't expect it to make any more power on a properly tuned engine though. I would also think the ECU will be fighting you on the long term fuel trim....maybe not.