• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

#1 Resistor?

C

confuzed_guy

New Member
Messages
9
Reaction score
0
Okay, I am a little slow as how these PMD resistors work. I am under the impression that #1 is on the lean side while #9 is on the rich side.

I have been kinda bitten by the "save fuel" bug but I am wondering just how "lean" is numer 1? I have other reasons to run her lean but I guess the question is - what's really the difference?

Thanks in advance!
 
OK, here's the deal... the calibration resistor changes the amount of fuel that your IP can deliver per 1000 strokes, in mm^3. It is like a 'trim' setting, that adjusts the IP so that it outputs the amount of fuel the PCM THINKS it is...

Now... that being said... if your truck isn't going fast enough, you push harder on the pedal... and that has WAY more impact than changing resistors. If you want to save fuel, put a brick under the pedal... the resistor won't do it.
 
JiFaire said:
OK, here's the deal... the calibration resistor changes the amount of fuel that your IP can deliver per 1000 strokes, in mm^3. It is like a 'trim' setting, that adjusts the IP so that it outputs the amount of fuel the PCM THINKS it is...

Now... that being said... if your truck isn't going fast enough, you push harder on the pedal... and that has WAY more impact than changing resistors. If you want to save fuel, put a brick under the pedal... the resistor won't do it.
Click to expand...
Thanks for the reply. Actually, what I plan to do is add a supplemental fuel. I'm kinda into the whole "alternative" fuel thing. That includes HHO but in this case the supplemental fuel will be a vaporized kerosene.

But I know this probably isn't the place for this kind of discussion. But that is the real reason for the #1 resistor. I even PM'd TD in reference to his "feeding the beast" modification - in reality, I want to see if that mod can be done in REVERSE - less fuel through the IP thereby allowing me to supplement via vapoized fuel. I know I can still supplement via vaporized and probably burn more fuel but that'll mean EGTs and stuff possibly going through the roof.

Oh well, it's all just fun experimentation. Will it work? Don't know but I am thinking so. Perhaps going to a manual IP is my best bet but I want to try other options first.
 
confuzed_guy said:
Okay, I am a little slow as how these PMD resistors work. I am under the impression that #1 is on the lean side while #9 is on the rich side.

I have been kinda bitten by the "save fuel" bug but I am wondering just how "lean" is numer 1? I have other reasons to run her lean but I guess the question is - what's really the difference?

Thanks in advance!
Click to expand...

Your thinking of this the wrong way. Your thinking gasser where you have a lean or rich air fuel ratio. Diesels do not have a lean air fuel mixture per say as adding more fuel makes more power essentially so long as you have enough air to burn it. A #1 resistor would simply limit the amount of fuel that the injection pump could deliver at WOT. It would still take a certain amount of fuel to make a certain amount of power to propel your vehicle at a certain speed with a diesel. It's not like a gas engine where you can lean the mixture down and use less fuel. Changing the resistor would not save you ANY fuel whatsoever(unless you drive on the floor board all the time), your right foot is the one that will save you there. A chip/reflash can save you some fuel by optimizing the injection timing to boost levels and fuel amount better than factory hence yielding better economy.
 
THEFERMANATOR said:
Your thinking of this the wrong way. Your thinking gasser where you have a lean or rich air fuel ratio. Diesels do not have a lean air fuel mixture per say as adding more fuel makes more power essentially so long as you have enough air to burn it. A #1 resistor would simply limit the amount of fuel that the injection pump could deliver at WOT. It would still take a certain amount of fuel to make a certain amount of power to propel your vehicle at a certain speed with a diesel. It's not like a gas engine where you can lean the mixture down and use less fuel. Changing the resistor would not save you ANY fuel whatsoever(unless you drive on the floor board all the time), your right foot is the one that will save you there. A chip/reflash can save you some fuel by optimizing the injection timing to boost levels and fuel amount better than factory hence yielding better economy.
Click to expand...
Yes you are right about the rich/lean mixture. I'm kinda looking for the spectrum for the reasons stated in my 2nd post. I plan on supplementing vaporized fuel via the intake - kinda like supplementing with propane.

Obviously, vaporized fuel burn much more efficiently than atomized fuel as atomized fuel is just tiny liquid particles with more surface area of fuel vapor to ignite. Of course, the incomplete/inefficient combustion of fuel is expelled as pollutants and heat.

Just experimenting... Got a theory but need a little better understanding of how the electronic IPs work... Now ignition timing, that would be very helpful...
 
You need to understand that adding supplemental fuel to a diesel in the way you envision will cause the engine to have a new baseline idle and horsepower... you can't 'cut back' on the diesel fuel except by letting up on the pedal.

If, for instance, you drive your pickup onto a wellsite with methane venting to atmosphere, it will rev up and run on you, whether you touch the pedal or not. Adding propane of HHO in sufficient quantity will do the same thing. What you want is a way to only start adding the supplemental fuel after a certain RPM; a way to control how much is added, which will let you quit adding more diesel and start adding more supplemental... almost like changing fuel sources.

Just some food for thought...
 
Think of it this way,

For any give speed and wind resistance, you need X amount of horse power to push the truck down the highway. On a Dyno, it takes Y amount of fuel to make X horse power.

Changing the resistor adjusts the amount of fuel supplied for a % of engine load. At Max power, 100% load, it adjust the amount of fuel available. Larger the resistor number, the more fuel at 100% load.

So, for that given X horse power, you apply more pedal with a lower resistor value and less pedal with a higher resistor value.

In the terms of maximum fuel, a #1 to #9 is about 3%.

In terms of mileage, highway, you may not see any difference. Around town, stop and go, you may save a little with the smaller resisitor and a light foot over using a #9.


I went from a #9 to a #5. With my saver driving style, I save about 0.5 mpg around town. In a heavy foot driving style around town, make that 1 mpg. (my primary style)

I have though about going to a #1 to limit the maximum fuel available when I launch off the line from the stop light. I would expect to go from 12mpg on a #9 to 14 mpg with a #1 in urban driving.
 
JiFaire said:
You need to understand that adding supplemental fuel to a diesel in the way you envision will cause the engine to have a new baseline idle and horsepower... you can't 'cut back' on the diesel fuel except by letting up on the pedal.
Click to expand...
And hence, my problem.

But vaporization at idle will be very light at best anyways. Again, the theory here is to use the vapors to make a MORE complete burn of the fuel, thereby needing less to make the same power.

The good thing about utilizing the exhaust to do this is because the more one steps on the throttle, the higher the volume of exhaust generated which will cause more vaporization of the fuel to take place. At the crossover there is only about 1 psi of pressure at idle - I thought it would be higher for some reason :p

Oh well, I'll give it a try and see where I go from there.
 
It's only ~5% from 1 to 9 - the IP was calibrated to a specific value resistor due to electro-mechanical deficiencies - run whatcha got and do some other things, as detailed in DIESEL POWER-AD's mag vis-a-vis the '96 Dodge 3500 ex-cab long-bed dooley - same applies to your Diesel-engined vehicle, whatever the flavor - can prolly still find that article on-line
 
midniteplowboyy said:
How are you going to keep your mix from preigniting under 21:1 compression? Engine longevity might outway the fuel savings.
Click to expand...
As far as I know, the flash point for vaporized diesel/kerosene is the same as for atomized - that is why I am choosing to vaporize fuel the diesel engine would normally utilize. Of course, I might be wrong here.
 
Deere Freek said:
would you even notice any seat of pants performance? from what i've seen it's not even worth thinking about....
Click to expand...
In this case, performance gains isn't what I was looking for in as much as mileage gains. But I have talked to Turbine Doc and after talking to him, I am hesitant as well - who wants to destroy an engine for a few extra miles?

Thank you all who replied. I have a bit to think about and as Turbine Doc told me, if I proceed I will do so ever more cautiously.
 
You must log in or register to reply here.
Back
Top