Unplug the coolant temp sensor

[blacksnapon]

Just remember, when you unplug the sensor (or have an open) it most generally tells the pcm -45 degrees. PCM now starts throwing fuel at it in an effort to get it to warm up.

 

[Skandocious]

Just remember, when you unplug the sensor (or have an open) it most generally tells the pcm -45 degrees. PCM now starts throwing fuel at it in an effort to get it to warm up.

I believe this is why eco wanted to try this in the first place. He said he wanted a richer fuel mixture to make more power.

 

[blacksnapon]

I think it'll be too rich.

 

[conanski]

Just to add to what has been thrown out here, the computer has a table assiciated with WOT fuel curves, and part of it is for learning. Over time the computer see's what fuel trims work at various engine loads and rpms and applies this to WOT operation. So because of this the motor will operate leaner in WOT than it will in OL, but it's will still be richer than CL. The last time I has the Tweecer hooked up I seem to remember the motor was running in the low 13's A/F ratio at WOT, but the computer had just been put back in so all it's learning had been wiped out.
In any event, disconnecting the ECT will certainly force OL and a rich mixture, and this will produce more power, but if you leave it this way it will also produce more engine wear over time as the fuel will wash more of the oil from the cylinders.

 

[eco]

What you posted shows absolutely NO advantage to disabling the ECT sensor, which was the OP's question!!!!!

Not necessarily disable, but possibly come up with a fixed reading at ~75* or whatever it takes to stay at a 13:1 ratio and a more aggressive timing curve....a ratio that would yield more performance, less economy and not rich enough to hurt the motor. I don't plan on doing this now, I want to know more about it though.

 

[eco]

Not true:

P0125 - This means that the engine coolant temperature (ECT) sensor indicates that the engine has not reached the required temperature level to enter closed-loop operation within a specified amount of time after starting the engine.

Hey Bob, that is a code for the EEC-V system, not EEC-IV...two completely different systems.

 

[Skandocious]

And, isn't putting a fixed value in for the ECT sensor disabling it......DUH

You are absolutely wrong here... The ECT is just a variable resistance resistor (as are a lot of the sensors in this truck). Depending on the temperature it receives, it changes the amount of resistance on the circuit going to and from the sensor. The computer reads the amount of resistance and uses a math equation to figure out how hot the engine is. If you put a FIXED resistance resistor, it will tell the computer that it is staying at a specific temperature, and you could control which temperature you want the computer to see by using different rated resistances on the fixed value resistor.

 

[Bob Ayers]

Thats a lie...

I could dig up the threads it prove it too.

No the fixed value isn't disabling because it is still sending the computer an input that it can work with.....DUH

"FIXED" value doesn't vary with temp, so you have basically diabled the ECT sensor.....any by the way, the ECT sensor isn't even in the circuit....DUH

Disable = NOT WORKING

 

[andym]

I broke my ECT off once. The engine ran exactly the same except for sucking lots more fuel. It didn't seem to have any more power at all.

 

[Skandocious]

I'm gonna clean this thread up and get rid of all the off-topic posts.

 

[eco]

"FIXED" value doesn't vary with temp, so you have basically diabled the ECT sensor.....any by the way, the ECT sensor isn't even in the circuit....DUH

Disable = NOT WORKING

Disable in this context would = to make unable to perform a certain action....not just NOT WORKING

So yes, it is unable to perfom the way the engineers wanted it to, BUT what if there was another way to get the system to perform well and to perform more suited to the users preferance? Disabling can be a good thing or a bad thing.

Or lets say you use a variable resistor controlled by a rotory knob. That would be kinda like a manual choke. With that set up you could set it rich for starting, then rich enough to get performance without going far enough to over richen and hurt the motor. Or you could put it in closed loop if you want.

 

[blacksnapon]

Personally, if you're just wanting to get more fuel, why not get injectors with more fuel flow? Then just leave the ect in the system.

 

[Skandocious]

Personally, if you're just wanting to get more fuel, why not get injectors with more fuel flow? Then just leave the ect in the system.

Injectors and a good computer mod like a TwEECer.

 

[eco]

Personally, if you're just wanting to get more fuel, why not get injectors with more fuel flow? Then just leave the ect in the system.

That, or an IST air adjuster (which I have), or more fuel pressure etc. but my thought was that the O2 would just try to lean it back out once it gets into closed loop.

This isn't something I want to do (unless I learn more about it and decide on it), it's something that I heard about. Not just more fuel, but open loop so the O2 doesn't fight it and you also get a mroe aggresive timing curve. I heard about it but I don't know all the details as to how it was set up. I just heard that it was done and the results were good.

 

[Skandocious]

If you're worried about the o2 sensor fighting it, then how about figuring out a way to control the o2 sensor circuit rather than the ECT circuit?

 

[blacksnapon]

That, or an IST air adjuster (which I have), or more fuel pressure etc. but my thought was that the O2 would just try to lean it back out once it gets into closed loop.

This isn't something I want to do (unless I learn more about it and decide on it), it's something that I heard about. Not just more fuel, but open loop so the O2 doesn't fight it and you also get a mroe aggresive timing curve. I heard about it but I don't know all the details as to how it was set up. I just heard that it was done and the results were good.

You have more than enough fuel pressure (until you get a ridiculous amount of horsepower). Just concentrate on using the pressure you have, more efficiently. A good quality controller can adjust the necessary perameters.

 

[eco]

If you're worried about the o2 sensor fighting it, then how about figuring out a way to control the o2 sensor circuit rather than the ECT circuit?

These guys at the race track that I saw (thats where I heard about this) stayed in open loop and had it rigged to run at just over 13:1. They presumably used a gas analyzer to fine tune. They only way that I can think of staying in open loop is to do so via the ECT. I also assume they had the ECT input to the computer rigged to achieve the AF ratio. I kid you not, that truck hauled some serious ass. It was an all stock motor and engine management system other than this mod.

This may be achievable via the O2, but thats a MUCH more complex sensor than the ECT and I don't have any idea how to take control of the reading it sends to the computer.

 

[eco]

You have more than enough fuel pressure (until you get a ridiculous amount of horsepower). Just concentrate on using the pressure you have, more efficiently. A good quality controller can adjust the necessary perameters.

I understand that, but how do you use (for example) an adjustable fuel pressure regulator to slightly raise the fuel pressure that the injectors see without the O2 sensor fighting the adjustment and then leaning in back out and eventually setting a hard trouble code once the O2 is unable to get the AF ratio back where the computer thinks it should be....ie a "HEGO voltage high / system rich" code?

 

[blacksnapon]

I understand that, but how do you use (for example) an adjustable fuel pressure regulator to slightly raise the fuel pressure that the injectors see without the O2 sensor fighting the adjustment and then leaning in back out and eventually setting a hard trouble code once the O2 is unable to get the AF ratio back where the computer thinks it should be?

Your fuel pressure on the eec 4 system isnt real critical as far as making adjustments. It concentrates on regulating air flow. It regulates air flow, while using a fuel pressure thats basicly "set". The o2 sensors will measure the oxygen in the exhaust, not the fuel.

 

[NeXtras]

I'm gonna clean this thread up and get rid of all the off-topic posts.

ohh haha no wonder my post dissapeared..

to be on topic.. what is Open loop exactly?