First up, apologies for the lack of pics and videos as promised. My day job has perked up because of the end of the year. But it has given me the chance to drive the car around a lot more and here is the rest of the story...
So off it went to RDD HQ for a Fuel Miser install.
Installation of the Fuel Miser for the Palio turned out to be a little more challenging than I thought it would be. First off the stock narrow-band O2 sensor was completely jammed in the header. Apparently a common problem in most cars, because the O2 sensor is the least checked/serviced part until a check engine light shows up on the dash and only then it is checked/changed. Most cars are running around with a failed sensor and wouldn't even know that it is killing their mileage and power. So the whole header had to be pulled out to extract the stock O2 sensor. Once that was done, back it went to RDD HQ for installation.
Now each ECU is different from the other and that little or no information is available about the Palio 1.6's Magnetti Marelli IAW 4AF made things a lot trickier. For starters while testing we unhooked the stock narrow band O2 sensor completely to initiate a check engine light, like in most cars. But in the Palio, nothing! The car started up and kept running like normal with no sign of anything out of the ordinary. The panic started. Either this is an antiquated ECU running open loop most of the time and only under certain conditions checks for the O2 reading or this is a really smart ECU that has detected that something is out of the ordinary and switched to a default map. But connecting to the Palio ECU is easier said than done because FIAT does not provide an OBD port for the ECU instead using a proprietary FIAT ScanPort to connect to the ECU. So Ron fashioned a new cable using an OBD2 board and cable he had lying around and we plug into the ECU. Voila! There were error codes stacked up in the ECU going back to the day the car was purchased and the coolant was supposed to have boiled over because of air in the coolant system.
There were also Lambda (O2) sensor errors which meant that the ECU had sensed that something was off and switched to a default mode wherein it would ignore the O2 sensor reading and run a rich map with lot of fuel to protect the engine. Turns out this ECU is a really smart cookie! I wonder how many Palio owners are driving around without realising why they're getting crap mileage because their ECU has switched to a default mode and running rich. So the error codes were cleared, the Fuel Miser was hooked up and the fun began! So with the wideband oxygen sensor in the Fuel Miser telling me exactly what air-fuel ratio the engine is running at all times, we confirmed that the Palios are indeed programmed to run rich, which explains the crappy mileage even when not in ECU default mode. The rich mixture is apparently a common practice by the factory to protect the engine and the catalytic converter from the varying conditions of usage, elevation, fuel, etc that their engines are likely to see.
In the ECU default mode we constantly saw AFRs of 10.5-11.5:1 which is filthy rich, even with the error codes cleared the AFRs remained at 11-12:1. By then Ron had also completed an evolution of the existing software in the Fuel Miser, so that also went into my car. Then the testing began...
The Power Mode air-fuel ratio was initially set to 13:1 and the Mileage mode was set to 16:1. The modes can be switched on-the-fly. In mileage mode the engine felt tractable and cruising speeds were easily achievable and you can easily cruise around at 80kmph all day in the city keeping the engine around 3000rpms and have no loss of power in any gear. Anything beyond 3000rpm feels a bit sluggish. Though in the mileage mode and the temp gauge never went even to the mid-point at anytime. But Ron has advised against Mileage mode in bumper-to-bumper traffic to protect the O2 sensor from overheating.
Now I have had the good fortune to drive a few fast cars in my time and was already quite impressed by the acceleration of the stock Palio for a car in its class. But I did not expect what followed when I flicked that Fuel Miser switch into the Power mode. Now I am not claiming that it suddenly started making more power. This is after all a stock car. What changed dramatically, orgasmically even, was the throttle response or even "power under the curve". The engine feels like its connected to the gas pedal. No sooner than you decide in your mind to move the gas pedal with your foot, you feel a satisfying surge forward starting from just under 2000rpm, the party really starts at 3500rpm and goes all the way till the redline. 80kmph to 140kmph between 3rd and 4th gear happens before I can think "OH NO! THAT'S A VERY EXPENSIVE AUDI, I AM ABOUT TO REAR-END! AND I HAVE SHITTY BRAKES!!". I'll be honest, that's all the courage I have had to test on my way to work. I'll tell you what, I have no complaints!!!
The difference in fuel efficiency post the install is why I wanted to post videos of the AFRs. Because there is no simpler way to put it other than that the fuel efficiency for my FIAT Palio 1.6 is now at 15-16kmpl with the AC on. I can already sense the disbelief
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To give you a fair idea of the improvement in fuel efficiency here are the facts:
I drive between Bellandur, where I live, and Electronic City, where I work. Thats a daily commute of 35kms every day and over the last three days I have used up 500Rs of petrol. And I have been driving around in the stoichiometric mode of 14.7:1 and not even the mileage mode. I commute around 4PM in the evening and 3AM in the morning and speeds are generally around 50kmph and once I am on the elevated highway my speeds are generally 90-140kmph, traffic permitting, which is around 3500rpm between 3rd to 5th gear.
Things're so good that for the first time since I got the car, I am considering commuting by car and even have the courage to keep the AC on in traffic.
