PC3 Maps

[Chuck35]

32 mpg was measured with not2shabby's map, which as I recall was made for a similar setup. I have tried other maps and none ran as well, none offered great mileage.

I did ride around a bit with a windows tablet connected to the PC3 to get an idea what cells I wanted leaner. Basically 3750 to 4250 @ 5, 10, and 20% should cover it.

I've also been looking for reasons that I might be getting worse mpg than others on the same maps. I have an o2 sensor eliminator installed. It may do something, the check engine light has never came on. The Barbarian mod had been done, all co's are at 10 now which I believe is stock for an 08. Gen2 is a return-less fuel system with psi regulated in the pump, so that rules out a vacuum line off misrouted or clogged to the psi regulator. I was getting the code 14 for Intake air pressure sensor hose clogged awhile back on cold starts. I cleaned the hoses and ports and it hasn't returned.

 

[RaYzerman19]

I have an o2 sensor eliminator installed. It may do something, the check engine light has never came on.

Curious, Chuck, what is this device? I thought when one had a PC one just leaves the O2 disconnected........ Just a thought that any device connected may affect fueling.

 

[Fred W]

I've also been looking for reasons that I might be getting worse mpg than others on the same maps. I have an o2 sensor eliminator installed.

Bingo! There is no need or want for an O2 sensor eliminator on an FJR. Just unplug the sensor and the ECU will be content (no CEL codes) but more importantly it will force the ECU to never enter into "closed loop" mode. If you have an eliminator that is feeding the ECU a fake signal that it interprets as a "reasonable" O2 sensor feedback signal, it will allow the FI to go into closed loop mode, which over-rides both the ECU's stock fueling rates and the Power Commanders add or subtracted rates. This would only apply to idle and "cruising", which is exactly where your bad mpg is happening.

Ditch the eliminator and see what you get for mpg.

 

[Chuck35]

Excellent! Thank you Fred!

This will be my next test!

I had read reports of the mil coming on during extended rides and wanted to avoid that. I was also unsure if the ecu even attempted closed loop at cruise.

I'll post up my results here.

 

[900gc]

If you still get the dyno work done, curious minds want to know what the fuel/air ratio looks like with, and then without, the eliminator. And of course, what the finished PC map looks like. It's fun spending others $$.

 

[Chuck35]

Well I really thought Fred had nailed it. I measured 32mpg on another pair of 2 gallon runs.

I did make a couple of conclusions though. I also have a speedo healer installed. while the odometer is accurate, the odometer is slow. Using my gps mileage between fuel stops its 35mpg. Not quite as atrocious. I need a longer run for accurate conclusions. The shop (auto & bike)I had emailed about mapping just got back to me, they have lost their bike tech.

 

[Fred W]

Darn, I thought that was going to be it.

OK, more ideas:

Try loading a zero map in the PC3 for a couple of days. Just save the one you are running on your PC first (if you don't already have a copy) so you can reload it later.

If that doesn't help, try bypassing the PC3 completely (just put the injector cables back to normal and leave the PC3 otherwise installed).

Those two tests will prove whether the problem is your PC3 / map or something else on the bike before you spend a bunch of money remapping. If the mileage is still FUBAR with the PC3 out of the picture you'll want to fix the other issues before getting the custom map.

 

[Denver_FJR]

Yep, I got 32 mpg on my trip to Jax and the SS1000. This was at a steady 75 - 80 mph.

Was this recent? I'm wondering if the poor fuel economy is just related to winter gas (and combined with your slow odometer). Folks post up every winter asking for help about why their economy has dropped.

 

[Chuck35]

Darn, I thought that was going to be it.
OK, more ideas:

Try loading a zero map in the PC3 for a couple of days. Just save the one you are running on your PC first (if you don't already have a copy) so you can reload it later.

If that doesn't help, try bypassing the PC3 completely (just put the injector cables back to normal and leave the PC3 otherwise installed).

Those two tests will prove whether the problem is your PC3 / map or something else on the bike before you spend a bunch of money remapping. If the mileage is still FUBAR with the PC3 out of the picture you'll want to fix the other issues before getting the custom map.

Great Ideas as usual Fred, I am hesitant to zero map / disable the PC3 with the 4 into 2 holeshots installed. I have a couple of stock manifolds (with and without cats) if I have to go that far. I have an 09 ecu (upgrade?) as well as a map sensor in route. These were cheap and I have wondered about the 09 - 12 ecu upgrade.

Yep, I got 32 mpg on my trip to Jax and the SS1000. This was at a steady 75 - 80 mph.

Was this recent? I'm wondering if the poor fuel economy is just related to winter gas (and combined with your slow odometer). Folks post up every winter asking for help about why their economy has dropped.

I hadn't considered winter fuel blends, but if that could account for 2 or 3 mpg it would put me about in the range expected.

I had never driven calmly enough or long enough to worry about mpg before. (due to odometer inaccuracies my actual mpg was 35)

 

[Fred W]

Chuck,

I forgot that you'd mentioned that you've changed your header out. I probably wouldn't be all that concerned about damaging anything from the reduced back pressure of the exhaust changes you've made. I doubt it really leans anything out that much, though it already does run lean stock. I wouldn't advocate leaving it that way long term, but I don't think you'd cause any damage by running a few gallons through it that way as a test.

It'd be a pretty big PITA to go back to the stock exhaust just to run these tests.

PS - Do you have a big winter windshield mounted on there now?

 

[RaYzerman19]

I'd agree that running without the PC will hurt anything for a while, but normally the o2 sensor would have to be plugged in to be "normal". Since you don't have one now, not sure what positive or negative effect that will have, if any. However, you have to go for a few tanks with the "o2 sensor eliminator" unplugged first (PCIII connected). We don't know what that thing does........

I haven't found the Rifle barn door windshield to have any real effect on mileage. Most probable cause of winter mileage being down is simply the colder temperatures. Winter gas has isopropanol or methanol added as a 'dryer', but do you have that down there in the sunny south?

I am also skeptical that an '09 ECU is going to improve mileage over an '08 ECU (with o2 sensor connected as in OEM condition), might have a minor beneficial effect on driveability. However, all that goes out the window when a PCIII is connected and overrides the fuel mapping.

 

[Chuck35]

I have a rifle barn door installed, year round.

There are many unknowns in our ecu's, we know nothing about ignition mapping for example and it isn't addressed with a power commander. I'm hoping the 09 ecu is a general upgrade, of course running the headers will still require fuel remapping.

In the automotive world ecu's have "learned values" these take a pretty good while to adjust themselves.

It is still quite possible Fred hit the nail on the head about the O2 eliminator. It may just take a good bit of riding to see the change.

The advise not to get a map done yet is spot on

 

[Fred W]

The ECU runs open loop (no O2 significance) most of the time anyway, so I don't think it will matter too much from an engine damage standpoint, but you have a point that it may be responsible for some of the loss of mileage.

Unfortunately, Chuck, the FJR's ECU is pretty dumb compared to a modern automotive OBD-II type ECU and doesn't have any ability to "learn" fuel trim. It just has the pre-programmed base fuel and ignition maps and the various sensor inputs to trim them (the O2 sensor being one of those). Since unplugging the O2 eliminator didn't cause a change in symptoms, I am suspecting that one of the other sensors that inputs into the ECU is responsible, but it would be nice to eliminate the PCIII before going down that path.

FWIW my mileage goes in the toilet up here in the winter, from 40-42 mpg summer to 35-36 in winter months when I can ride. But we get a pretty severe change in the winter fuel mix, and I go from a pretty small windshield to a monster Gen 1 Rifle touring barn door (can't stand the heat behind that thing in the summer). Plus the air density difference between 90 degrees and 35 degrees is significant.

 

[Denver_FJR]

Unfortunately, Chuck, the FJR's ECU is pretty dumb compared to a modern automotive OBD-II type ECU and doesn't have any ability to "learn" fuel trim. It just has the pre-programmed base fuel and ignition maps and the various sensor inputs to trim them (the O2 sensor being one of those).

Pretty dumb ECU? Yeah, have to agree with that!

Regarding no ability to learn fuel trim, do you not think it has long and short term trim memory?

 

[Fred W]

No. I am fairly certain that it has none

 

[Denver_FJR]

My fingers outran my brain a bit. Not having a long term fuel trim is plausible, but I think the ECU must have a short term trim for a couple reasons.

• The nature of a narrow band O2 sensor prevents the ECU from "knowing" how rich or lean the exhaust is. All the ECU can do is increment/decrement the trim a predetermined amount based on the rich/lean signal from the O2 sensor.
• The factory manual shows the ECU can throw codes 31 & 32 for excessive rich/lean conditions. I'm guessing this is based on a short term trim reaching some upper/lower threshold.

All conjecture by me of course, I don't have any secret insight into the ECU.