Does anyone know if the pfc has a fuel cut on decel to conserve gas and does anyone know if the datalogit can turn this off, i'm thinking about going premix.

 

Check out Settings 1 on the datalogit FC Edit software for Fuel Cut values with Electrical load, A/C, and neither.
I think you can access that on the PowerFC commander too .

 

I can access this value through my commander but i'm wondering what the valve refers to. I think the base setting is fairly low, if i set it pass my redline will it mean that the fuel cut decel will be turned off since i will not rev past that value. Am i making any sense? Anyone else running premix, i did a search but didnt come up with anything.

 

Not sure either. I noticed an improvement when I set back the settings to stock though from what someone else had changed it to. My car doesn't stall now so much (well not very often). I'm guessing that's what it was.

I use the Pettit Fuel lubricant and have since my rebuild the other month. What are you concerned about with it?

 

Well imagine if i disable the stock oil injection and only us premix in the gas tank, and when i go full throttle and let off the gas and the computer cuts out the fuel, the engine wont be lubricated. It would probably be only for a short time, but its this short time that i am afraid of. I want to use premix because i think its a better form of luberciation than the stock oil injection. I used it on my TII and had no ill effects at all, no odd smells or smoke at all and i was running a pretty low ration of premix to gas.

 

I was under the impression that during decel (no gas) the OMP does not send any oil. I guess we could test that by looking at the voltage going to the OMP during decel. Anyone know for sure?

 

The value in the commander is the RPM at which the fuel cut will end, and the injectors will come back "on line" you can see this if you Monitor the injector duty cycle.

I believe if you set the value in the commander to "0" that the fuel will never cut. I seem to recall that there is also a minimum value that will stick, and if you set it below that, but above 0, it will stay at that minimum (wouldn't make sense for it to be lower than idle, for example).

 

I'll set it to 0 and i'll see what the duty cycles are when i go into decel, i wonder if i can test this at idle? Anyone else with more suggestions?

 

You said that i would make send for it to be set lower than idle but if i set it to 0, that would be under idle. Maybe i'm not reading it right or something.

 

I was taking a look at the OMP voltage on the sensor check area on the commander. When I went into decel (0% injector duty) the voltage going to the OMP drops to the same level that it is at idle, regardless of how high my rpms were. What sucks is that even premix would'nt help becouse the injectors remain off. I tried the zero thing, but my comander would let me go that low. Maybe I'll try it with the datalogit.

 

Rx7will, Sorry for the confusion.

"0" is special. The people who created the PFC probably needed a way to tell the PFC to disable the feature and never cut fuel in the first place. Instead of making a special setting, they figured "0" would work. Obviously if the fuel cut when you lift of the gas and only came on at 0 rpms... the car would die.

 

Yeah, i tried to lower the value to 0, but it wouldnt let me, and i looked at the injector duty cycle and it does go to 0% on decel. I guess i'll just add a little of premix just for a little extra. Let me know if you can turn the fuel cut decel off with the datalogit.

 

Damn - my memory has gone. I know it can be done, but don't have the manual here. Does anyone know where one is posted on-line? <nudge> that would be a great sticky post - the on-line manual ,/nudge>

 

in the mean time, you could try setting the value to 8000 or as high as it will go..... That should prevent fuel cut.

 

I tried that and it still cuts out. I read the manual and it does not say anything about turn off the fuel cut on decel. I guess they want you to leave it on to save gas.

 

I read the manual too. Hmmmm... I have an inquiry in with the person who I remember telling be about this feature. We will see. Sorry for the missinformation so far.

 

Here is the response:
"diable fuel cut you go to settings...idle...and then to a/e decell ..e/l decell..and a/c deccel...and raise the fuel cut on values to
8100 rpm...then the car never fuel cuts"

I haven't tried it myself - hope it works.

 

Anyone try this yet?

 

I tried it, worked great. The car is much smoother and easier to drive at low rpm, idling through traffic. much less bucking. However with no fuel cut in the upper rpm range my car now shoots 2ft flames when I shift above 5k. Looks cool though..