Gamefreakgc

Anyone here ever do this, and can they speak to whether it makes any difference?

http://www.midiwall.com/4Runner/ect.html

The original thread: https://www.yotatech.com/forums/f130...ect-mod-75163/

bone collector

im sure it works, say goodbye to gas mileage tho...

scope103

How would an over-rich mixture give more power? I think I'd need to see some dyno numbers before I'd believe that one.

Note that you'll also lose overdrive if you mess with the ECT sensor.

jerry507

Yea, I don't buy it either.

Gamefreakgc

The thought behind it is that it will further advance timing and provide more fuel, creating more power.

I read up on it more and it looks like some people have done the ECT and the IAT (Intake Air Temp sensor) and found that the IAT provide more results. By thinking the air is colder, it provides more fuel and advances timing.

Granted, this is NOT for long-term use, hence the dial that you can adjust. The thought is that it provides short term boost, for on the trail or for just normal drivng. It could be installed as a dial for fine-tuning or just a switch.

I realize long term affects of leaving it on would mean the ECU would adjust after a few cycles (I've messed with my truck enough to know it takes a few times of running the truck, shutting it off and repeating before the ECU fully adjusts) and you'd run the risk of pinging due to over-advanced timing. In short uses, it might work though. The thought behind it makes sense to me.

Just was wondering if anyone's done it. I dug around and found one person who did it on youtube with an A/F ratio meter and it does indeed richen the mixture immediately. It'll only cost me $15 or so for both parts. I can easily return to stock. I'll be down there soon wiring a kill switch anyhow.

Punchy

I run an O2 sensor on my 3vz for years and see no use in richening the mixture, As for advancing the timing then why not just advance it and keep as close to staich as possible.
The engine runs really rich already in open loop.

The only thing I can think this would help would be in high altitude situations where you can fool it into thinking its hot air and forces the engine to lean out due to lack of O2 in the air, Again pointless as the O2 sensor would see this and compensate.

Off note,,, Isnt the ECT the Electronic Controled Transmission?

jerry507

If you were going to do it, I'd spend the time to be able to switch between the pot and the actual sensor.

I'm working on tracking down some issues with my sender, and I am using the ECT as a comparison point because it's characterized in the FSM, so I can speak to some practical issues with this. The main issue with these things is they're logarithmic thermistors.

The guy in the first link uses a 500 ohm linear pot. That gives him a range of about 50C to 120C, but it's linear not logarithmic so it'll be a PITA to actually set it. You're not going to set it on the fly on the trail. So it's much more useful to be switching between a pot and the sensor so you can go between a good mileage mode and a "performance" mode.

The other question is how quickly does the idle change with temp. That can make it really hard to set it too if the idle is high from 50C to 90C and drops quickly past that. But that's just another reason to set it once and switch to the sensor for DD.

One thing to note too, on our trucks the ecu controls fuel with the cold start injector and timing, but idle air is controlled by a mechanical valve based on actual coolant temp. That means that you'll have to readjust, perhaps considerably, over temperature swings.

scope103

Yeah, that too. Engine Coolant Temperature.

Thermister (variable resistance); a thermocouple is something different (generating a very tiny voltage). Not that it matters in the end.

jerry507

Opps, thanks for the correction!

Gamefreakgc

Yeah, that makes sense. I was thinking of putting a numbered knob on the pot so that I can easily adjust and record. I found a video of someone doing this same mod with what you suggested, a dial and a switch. The dial to fine tune and the switch to turn on and off.

I was looking at the graphs and data from the FSM and I understand the exponential change in ohms, both for the IAT and the ECT. With a numbered dial and say, a 1k ohm resistor I could be precise. If I turn the dial to "2" out of 10 max, I know I've added 200 ohm of resistance. With the charts, I'd know what temp I'm sending to the ECU.

Anyway, what does everything think? Maybe I'll be the guinea pig?

jerry507

Yea, try a 1k at first but I suspect you'll eventually go to a smaller pot. It'd make it a lot easier to set it without buying a 12$ 10 turn pot.

scope103

I was going to say "it won't cost much, so give it a try."

But I'm afraid I know where this is going. You'll horse around with this for months, trying different size resistors, pots, relays, switches. Along the way you'll replace your cat and O2 sensor (because all the time running over-rich sure isn't going to do them any good). Eventually you'll get it to the point where it at least runs, probably because the added resistance is so small it's still within the temp. tolerance of the ECT sensor.

And after all that hard work, surely it must have done something? So you'll believe that it did, and you'll report "noticeable increase in horsepower."

But is it an actual increase in horsepower? Without a legitimate before-and-after dynamometer run, I'll just keep my opinion to myself.

Gamefreakgc

Haha, I know what you mean scope.

I'm not one to beat a dead horse though. If a 1k ohm pot doesn't do it, I'm just going to rip the thing out and wire it back together. I know the consequences of the truck running rich long-term, it was like that when I got it and the P/O had to put in a new cat when they sold it to me.

The only mod I've done that increased HP by any significant amount was the cat-back system. I don't expect this to do that. What I'm hoping for is kind of like a "performance boost" much like some newer cars have. A short term adjustment that gives a little kick when the driver needs it. That's my thought, anyway.