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Originally Posted by dustom_99 I see no one paying 80$ an hour for regular maintenance here. People who pay 80$ an hour are the ones looking to make there Fi do what it wasn't programmed to from factory. |
Trouble in this case (vs. the N. American labor rates referred to) is not routine maintenance or modified systems, it's the fact of frequent failures with RE's budget Keihin FI system as used on the CL500's, etc. Not $80 an hour for labor, but Rs12,000 fuel pumps going bad on <2 year old bikes (see below) is expensive in my book. My theory is that current Indian-market FI systems – which seem rather crude and rudimentary for lack of sensors - are fitted more with marketing and profit margins in mind, rather than operational superiority. That would be precisely why you're seeing them on premium mid-market variants, and not on lower-margin 100cc segment machines (which, tellingly, even with carbs manage the highest FE ratings, DO pass emission norms, and remain the cheapest to maintain models in the long run!).
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Originally Posted by dustom_99 Altitude compensation is done by MAP sensor, not by O2 sensors. I am not sure if report about REs inability to adjust AFR for altitude is true or not but this kind of knowhow is very basic. |
After your reply I had to check whether I was mistaken here (it's been a long time since I worked in the ECU/MAF departments), but I wasn't. If you doubts about this understanding of the 02 sensor's role in engine control, read this, which is very clear on this point:
http://www.enginebasics.com/EFI%20Tu...Loop%20o2.html:
“Using the o2 sensor the ECU will modify its fuel table based on the readings the o2 sensor is seeing. This is important in maintaining a perfect A/F ratio as there are so many variables affecting the tune of a motor at any given time. For example, air temperature,
altitude, humidity, and so on.[/i]
So the truth is that all the pre-programmed fuel/ignition curves in the ECU are only theoretically “correct”. All other sensors – MAP/MAF, TPS, temp, crank angle, etc, feed info into the ECU, and it compensates according to how much fuel/advance SHOULD (ideally) be required at a given manifold absolute pressure (MAP sensor), rpm (crank angle sensor), load (MAF/TPS), engine/ambient temp (temp sensor), etc.
BUT the O2 sensor is the final arbiter, you could say, and different from all the other sensors in that it can sense how the combustion process is ACTUALLY going (not just how it SHOULD be going), and adjusting as needed AWAY FROM the pre-set “ideal” curves when necessary. It does this essentially by measuring / sending a rich/lean indication to the ECU. So it definitely does play a major role, along with the MAP/MAF and every other sensor feeding into the control unit, towards idealizing A/F ratio across a wide range of rpm's/loads/climates/levels of engine wear/etc. The O2 sensor IS a definitely an important one, but unfortunately it's expensive (Rs5,000+), so the FI systems on Indian bikes aren't using them (RE's export models do, incidentally).
So RE's domestic-market Keihin FI systems are basically running in “open loop” (without 02 sensor or its measurements / inputs), and therefore only adjusting fuel/timing according to a theoretical ideal (i.e., the preset curves), rather than according to what an engine might actually more precisely NEED at any given time. This is NOT the most effective way to run an ECU-controlled FI engine! Note that in the article link below, it's saying that an ECU can be set up to adjust to a
maximum deviation from the curves - which could easily be 10-20%! That means that the ACTUAL ideal can often be pretty far from the theoretical ideal!
Anyway (correct me if I'm wrong) I don't know that RE's Keihin system has a MAP sensor, either, and probably not a cylinder head temp sensor, so it's really just got a TPS to estimate load, a crank angle sensor to know engine speed, and basic programmed fuel / timing curves telling how much of each to feed in. This is not really a lot of info for the ECU to go on - which is why it can't really get near ideal, and the 500CL (FI) was only giving 26-27kmpl locally here, where a bolt-on carb setup on the same bikes was giving 32-33.
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Originally Posted by dustom_99 Now almost all bikes are Fi in India , except the 100cc segment or thereabouts. |
This is really interesting news..!!! Granted, there ARE optional FI
variants of a number of mid-upper segment offerings, but in truth it turned out to be no advantage (and some disadvantage) on the P220 and they went back to a carb; the Hero showroom itself is telling me the FI-Karizma's are a nightmare to service/repair, and I've personally known of at least three people (and I don't run much in RE crowds) who had their fuel pumps (suddenly, without warning) fail on CL500's no more than a couple years old, at something like Rs12,000 a pop. And the FI RE's frequently were misbehaving at high altitude. Thus, as of last year, RE started using a fuel injector that had a little external adjustment screw on it, allowing it to be calibrated for various altitudes; Theoretically each dealership was supposed to have the equipment to measure/perform this correction, but doubtful whether they all do, and not likely that this is something that could be performed by the owner en route, which is actually when you'd like to be able to do it sometimes (Manali-Leh, where altitude variations along the way exceed 10,000ft!) and on a carb, easily COULD do it.
Granted, a carb will need to be adjusted at altitude to run at its best, too - but
the point, getting back to the Himalayan, is:
What's the advantage of FI if it's 1) not compensating any more than a carb would for varying conditions; 2) is not serviceable by a majority of small, non-factory-trained roadside mechanics one may encounter on long tours in out-of-the-way places; 3) in practice is actually giving lower FE numbers than the same bike converted to carb; 4) is not any more reliable (in fact less in practice) than a carb; 5) has MUCH higher replacement costs for components (conventional fuel system is really only a carb, at maybe Rs6,000-7,000, whereas the Keihin FI has a pump, injector, and ECU, totaling 25,000 or more)??? 6) even factory carb'd versions of the same engines (P220/RE500std) are meeting emission norms...??? So I'm going to pay this much more up front and assume this much liability for what? Not having to use a choke in the morning? (incidentally, last time I was in Spiti, a guy on a FI'd RE Desert Storm had been having a terrible time starting it every morning that week, whereas his companion on a carb'd AVL TB had no issues). Budget FI systems are NOT desirable or in any way worth it in my book. Mere marketing hype.
Long story short, I'm hoping the Himalayan will be brought to market as a simple, robust, affordable, and easy to self-service carbureted bike, and if it's not, and the FI system has not been significantly upgraded from earlier RE's, and I ever do own one, I'll probably be putting a carb on it.
-Eric