free website stats program fuel mileage bad | Page 2 | Harley Davidson Forums

fuel mileage bad

Running high test premium fuel means that the ion-sense knock retard feature is probably not kicking in and retarding your spark advance which would hurt your fuel mileage.
Just curious,, what's your average altitude where you ride. The Switchback is a 103 correct?

Reason I asked about the factory download was because I have seen a dealership download the incorrect stage 1 map to a new bike. Friend of mine that has a 103" had a stage 1 map downloaded to the bike that was actually for a 96". I would have thought the ECM would reject it but it didn't. The maps were correct but the VE was adjusted for 7 cu/in less.

Just my opinion but I just don't see a tuner improving the fuel mileage on a bike that does not have some type of pre-existing issue. Even if changing fuel pot settings was to "correct" a problem, you would still have an underlying issue that was just being masked or hidden by the tuner.




Good one Hoople...

I wonder IF taking the ground wire OFF (Loose) on the Dobeck tuner to see What the mileage is when HD is fully in-charge.?
Then you have a base level to look at.

signed....BUBBIE
 
to see What the mileage is when HD is fully in-charge.?

Bubbie, I read it as an average of 36 based on thread entry #3 by Marknett. I have friends with 103's that clock in the 40's without trying very hard. I was actually shocked my 96" got low 40's on flat open road at sea level,, but I didn't correct for the error below.....so I actually may be at 39 or a solid 40 at steady state road speed.

Hope this is not adding salt on the wounds for Marknett but when I first got my 2009, I checked the calibration of my speedo & odometer. I found the odometer to be pretty far off. And guess in who's favor it was off... HD's. If I covered .94 of road, the odometer said I went 1.00 mile. Doesn't sound like much but that's 5% or 2 miles based on 40 which is a bunch when it comes to MPG.
 
average altitude is 309'- 375' ... The switchback is a 103 engine and my mileage was averaging 37 early in the break-in . I bought the bike new and installed the stage 1 air cleaner and slip on's at factory at time of purchase so i don't have a true stock to refer from.
 
So when you took delivery of the new bike, it already had the dealerships stage 1 download with Vance/Hines slip on's & air cleaner. Ok

You would think that your mileage would be better using premium fuel at sea level. You know of two other Switchbacks that get in the 40's and I know of a couple of bone stock 103's that get in the 40's also. Unless you weigh 450 lbs, this doesn't make sense because I would expect your mileage to be better.
Check to see if you have any historical codes, especially ones associated with O2 sensors or engine temp senor. Don't go by the check engine light. Manually check it. It certainly could be a sensor that the ECM can't detect. The ECM diags are very basic unlike today's automotive ECMs. If your pristine clean of any codes (speedo says None), my first gut feeling says an incorrect file was loaded to the ECM. Other than poor fuel mileage, how does the bike perform, start and run.

I have an approach I would take if this was my bike but have you bounced this issue off the dealership yet? If so, what did they say. Don't take this question the wrong way, but you are filling the tank to the brim each time you compute the MPG. There is no question regarding the miles traveled and the fuel used. And you haven't changed any tire sizes, pulley ratios or anything like that.
 
I fill up to the rim everytime so I am getting accurate data. I talked to the dealership and they installed a generic map using a program harley davidson supplies called Digital Technician . This is a generic map that is used ,according to him, in all 50 states regardless of alitutude . If that is the case it has to be a very basic and very conservative map . Any other type map would require buying the sespt and dyno time . I could go with another aftermarket tuner and tune for mileage more I guess. The sespt is $460 plus dyno is $350 . He stated that 36 mpg was normal for the 103 engine


What would be your approach?
 
If that is the case it has to be a very basic and very conservative map .

I agree. If it's good in California, it has got to be lean.
He said 36 MPG was normal.
When you say 36 MPG, is that on a pure highway run? I could see maybe 36 with only city stop & go riding but never on the super-slab in 6th gear. In my mind, no way is 36 normal on the highway in 6th gear. No way, somethings wrong.

I forgot to ask if your bike has a Cat and if so what did you do with it?
 
I recently made a run to louisiana .thats about 400 miles round trip and still got around 36 to 37 .. I am running a complete D&D fat cat exhauist system now without a cat
 
In my opinion somethings not right. You should be getting more than that based on a 400 mile run. When you get a chance, manually check for historical codes. Other than poor fuel mileage, the performance is good. No engine surging, pinging or other issues.

From a stone cold start up, does the engine have a higher than normal idle RPM and then after a couple of minutes, it settles down to the 1000 RPM range. In other words, it goes through a normal warm up sequence like it should.

It's important that it does that. That is the transition stag from open loop to closed loop. Closed loop is necessary for good fuel mileage.
 
it cranks and goes 1350 to 1400 rpm's and very slowly ,very slowly comes down. ends up at around 1050 always fluctuating.

Went to texarcana yesterday to the dr. 119 miles round trip on interstate . I was running around 80 .. just filled up and checked mileage . 32 miles per gallon.
 
32 miles per gallon.

32 MPG on the road. That should convince just about anyone,,, even the dealership, that something is not right. Some of it may be caused by the tuner. It's just pouring too much fuel into the engine. You need to run without it to be sure. A cold 1400 RPM and comes down to 1050 sounds about right. It doesn't prove the ECM is in closed loop and without any warm up enrichment, but it sounds like it is. At 32 miles a gallon, you should be able to smell the richness of the exhaust because the engine can't be cleanly burning all that fuel.

Without taking some basic measurements, so many possibilities exist . You could rip through this problem in an hour if you had the right tools (checking HC & CO at exhaust pipes and viewing live data using a SEPST) but those tools few homeowners have in their garage.

Something simple like a bad O2 sensor could cause this so check for historical codes. You just may have a DTC sitting in there dieing to get out. If the error log is clean, is there another dealership you can go to and start fresh.
 
Back
Top