Muzzy fuel controller

Subject: Muzzy fuel controller May 14th 2012, 2:15 am

Here goes, I've got a muzzy fuel controller on my rzr. The settings got tampered with. Now I have to reset it, (the problem). When HRR built the engine (a modest 787 holz big bore w/46 mm throttle body,biillet intake n ported head,also holz primary n secondary clutch) it required more fuel. The muzzy only increases fuel not air, there r times thru out the band that it needs leaned out. I can put a sensor (o2) in the bung he welded on with a gauge. When I picked up my rzr (in Beckley) we rode it a little, it would smoke the tires on asphalt, hit the rev limiter in a heart beat but in NC it doesn't seem to have the same power. So do I keep adjusting on the fly with new gauge n sensor or bite the bullet n switch to dynojet auto tune with pc5 commander n the big ? Do I also have to run the commander v with these two other dynojet products? Please help I need input. One last thing it seems when u start changing things it never ends!!!!

Subject: Re: Muzzy fuel controller May 14th 2012, 7:20 am

Dave , a car computer will get in a loop , so it was set in wva at 3000 ft and then you brought it down to 800 ft ( which is about were we are ) I would expect a change . What you have to do in a car is let the diodes die in the electroic piece , unplug it from power for 24 hours , this will make it start up in a mode to learn what it needs to adjust instead of running the route it learned . I know you set a lot of stuff on those but some of the setting im sure it learns on its own . What altitude ( if you set it ) I would set at 2500 to 3000 . Reason being is that is where you intedend to ride . I don't have one of these controllers but would guess it just changes the fuel curve set by factory so it allows more fuel , but air is determined by the throttle body which I know you changed .

Subject: Re: Muzzy fuel controller May 14th 2012, 10:22 am

Punder/SuperDave,

Would your theory indicate that, if Superdave disconnected his battery, he's lost HRR's tune? Don't know if this happened and never thought it could - just asking.

If air at higher altitude is slightly less dense and the fuel map hasn't changed shouldn't the motor run leaner at a lower elevation? Or, does the T-BAP sensor take that out of consideration? If so, then maybe there's another issue or the T-BAP is bad. Thoughts

I bet James knows.

Subject: Re: Muzzy fuel controller May 14th 2012, 11:02 am

I was told some time back that the fuel injection on the Polaris uses a crude type air sensor ,not near as sensitive as a mass air flow , there is a good chance that it is off in some way or lacks the curve to do what he is wanting to do , plus there is not sensor in the Exhaust to read how rich it is in the tail , it basicly knows this RPM gets this much fuel per the set amont of air he has change both . I do know Dave changed the throttle body ( so he has more air ) , and this box should increase the fuel curve . As far as what James put in thru the computer to program is I would assume to be like your computer at home , if it is unplugged you retain your programs but sometimes a restart will correct problems with a computer like slow running . There is a good chance that he has another problem , one of them things were speed cost money how fast you want to go . I would clean the T-bap sensor ( was told you can use Mass Air flow cleaner , oil from K@N and other type oil filters can coat the sensor causing a false read . Newer model cars now do not want to be disconnected as it can cause a trip to the dealer that is why Auto Zone and places like that use a jump box thru the cig lighter to keep power to the computer . There is a AC delco place down from were I work , he had a car that was delived to him with a dead battery , it lcoked out the computer and called thru onstar cause it thougt it was being stole , but Cadilac is its own nightmare from what he told me .

Subject: Re: Muzzy fuel controller May 14th 2012, 12:25 pm

Ok following you two so far, I'll explain alittle better. The muzzy was set in WV, I think James tuned it perfect. Elevation is some what of a factor. I don't think it (the muzzy) lost its setting. Some friends were at the house this past weekend with their children. I had just finished installing water temp gauge. The rzr was running. I was checking, that the gauge was working properly. It was locked up, could not be moved, the seat was out n the muzzy was in reach of the kids n we left them unattended with directions not to get in or try anything of the sort. Well the younger of the two was interested in the light on the muzzy n so she started pushing the mode,+,~ buttons. She is a little sweetheart I might add n this was our (the adults' fault) for happening. Now, in researching the muzzy I found out it only controls fuel. James did put in a bung. To run correctly at all times I need an air/fuel gauge w/02 sensor so I can monitor n adjust on the fly according to weather n riding conditions(humid/dry,dusty/wet,cold/hot,one air filter or two etc). This is still possibly several hundred dollars.

Subject: Re: Muzzy fuel controller May 14th 2012, 12:31 pm

If I go to a dynojet set up it will be commander pcv v and auto tune. It is plug n play n forget. On the gauge that comes with plus the o2 sensor u set the ratio u desire (probably 13/1 or close to that) n the system makes adjustments thru out the throttle band/curve constantly. There r times it needs to be lean/rich. This also prevents leaning to a point that it is blow torch in the cylinder. 600 frickin dollars!

Subject: Re: Muzzy fuel controller May 14th 2012, 1:53 pm

It self adjusts!!!! I gotta get me one of those things. My a/f gauge has gotten a bit of dampness in it, and it some times goes plumb crazy, so I am neading to up grade.

Subject: Re: Muzzy fuel controller May 14th 2012, 1:59 pm

Yep , if it goes lean she gonna get fry but will be fast till it blows . If you plan to change the rest of the pieces as you have mentioned , I suggest getting the o2 sensor , with not reading on the exhaust you really have no idea unless you put it on a dyno , run a o2 sensor off the exhaust and adjust it all the way thru the range ,but that is even subject to being off when humidity and barometric pressures change . So you need a system that can read all those and adjust accordingly . Other words go get a Kia sportage with AC and heat and trade in the RZR ... problem solved .

Subject: Re: Muzzy fuel controller May 14th 2012, 3:18 pm

Go with the pc autotune, it will be able to adjust for altitude changes, based on the o2 sensor in the exhaust. They are the best set up out there for nodding your toys.

Subject: Re: Muzzy fuel controller May 14th 2012, 3:25 pm

The Polaris RZR has a fuel injection system which helps ensure that the engine’s performance remains consistent and is virtually unaffected by changes in temperature or altitude. This system measures coolant temperature, air intake temperature, air intake pressure, engine speed and throttle position, then automatically delivers the ideal amount of fuel to optimize power delivery.
Why can't this high-tech system deal with adding a free flowing aftermarket pipe and/or intake?
The simple answer is that unlike automotive applications, a fuel injected UTV does not have a mass air flow meter. Therefore, there is no way to measure the amount of air actually taken in by the engine.
The long answer requires a bit more understanding of how a fuel injected UTV works.
To run at the optimum level and achieve the highest power output, Dynojet has found that an air/fuel ratio (AFR) between 13.0 and 13.4 to 1 is best. A fuel injected UTV like the Polaris RZR uses a "map" that is built into the ECU to decide how much fuel to deliver at different points of the RPM curve. Various sensors on different systems allow the curve/map to be shifted up or down (richer or leaner) to compensate for altitude and air changes. These sensors do not really change the shape of the curve they just move it up and down a small amount.
Even if the fuel curve was perfect on a stock UTV, once you have altered the airflow through the engine (by changing the exhaust, intake, etc.) the table that the ECU uses to deliver the correct amount of fuel no longer matches the altered levels of airflow at different parts of the RPM range. One of the things to keep in mind is that not all modifications increase airflow throughout the RPM range. Often it is necessary to lean out certain areas of a fuel curve for peak output.
The best solution to this problem is to allow the user to add or subtract fuel at each 250 RPM increment and throttle position so that the new map matches the new airflow created by the addition of a pipe or intake.

Power Commander III:

The Power Commander is a fuel injection adjustment unit that plugs "inline" with the RZR’s stock ECU (electronic control unit). The PC uses original equipment style connectors, so no splicing or cutting of the harness is required.

Changes are made to the bikes fuel via the Power Commander's onboard microprocessor. With this technology, the PCIII offers a large area of adjustment without making any permanent changes to the bike’s ECU. Removing the Power Commander returns the bike to its previous stock condition. Each unit comes complete with software and cable link that allows you to change between different maps or make adjustments to a map file.
The competition's unit can only be adjusted externally and only modifies the length or duration of the fuel signal at low, medium and high RPM. Fuel can only be added - there is no capability to lean the curve out.
The Power Commander can be adjusted externally for fuel delivery at low, medium and high RPMs. The Power Commander also utilizes fuel maps that adjust fuel delivery at every 250 RPM along the entire power curve.

Subject: Re: Muzzy fuel controller May 14th 2012, 7:51 pm

Great narrative from sprinklerhead. For my Rat RZR project I had S&S re-flash my ECU for timing, rev limit and fuel according to how similar my changes are to their engine build-up. I have a PC III and (with HRR's help) will do the finish tuning with it.

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