Project Electronic Fuel Injection

[baddi]

Hey guys, Lego and acetone glue cant hold back pressured fuel, so for now i'm still running carb, untill i get the replacement parts.

After i put the carb back on, i decided to test the mixture with #80 jet, but i forgot that the rpm restriction in the injection are by cutting fuel and not the spark, so the rpm raised past 10.000 and here it got exiting:
At 11.500 RPM, the sound raised dramatically "WWRROOOOM" and it sounded like a 500cc motorcycle taking off, so i guess this is where the resonance point are on the Leo Vince exhaust, and it starts functioning as a tuning exhaust, sucking air out of the cylinder in the instance the exhaust valve is opened.

So i learned three things today:
- The Agility can handle 12.000 rpm with standart engine (exept exhaust) for a short amount of time.
- Lego-glue isn't strong enough for pressured fuel.
- The resonance point makes any engine sound f***ing fantastic and it is at 11.500 rpm with the Leo Vince exhaust.

[Mexwall]

Is there any progress on the idling problem?

[baddi]

Is there any progress on the idling problem?

Oh yeah. I am sorry for the lack of updates on this forum. The idling problem was that the sealing O-ring gasget between the throttle body and the intake manifold was too small because space had been carved to the O-ring in both the throttle body and in the manifold which is where the injector is. This would cause an air leak and enough air/fuel mixture to enter the cylinder to get the idle rpm rising.

I have driven this for months without problems and have been tuning it manually while reading the AFR with a wideband lambda sensor even though it can do self-tuning when there are a wideband lambda sensor attatched. But anyway.

It seems that the GY6 engine can hold idle rpm all the way down to 600 rpm, but i have not yet have had them stable below 800.
Also, when the engine is cold, i have trouble igniting a fuel mixture that is not enriched to AFR 11 or more and this causes some trouble, which i will figure out soon.

About the max rpm, i have recently found out that the 2010 agility has 2 springs per valve and the 2008 only has one, so do not attemt to hit 12.000 rpm if you only have 1 spring per valve.

Also, there is a restriction in the air filter about 7 cm from the carb intake which reduces the inside diameter by 1,6cm. When this is removed, the pressure after the throttle blade can be above ambient at WOT, so i guess the stock air box is not that much of a restriction. Also i have rounded all corners in the stock air filter and i have increased the diameter of the intake at the cylinder head to 24mm, so it matches with the EFI kit.

Even though the pressure is high with the stock air box, the Volumetric efficientcy is still only 80%, which is probably mainly because of the valves. If i can get a 4V cylinder head for less than the $400 a whole 139QMA-A engine will cost, i will try that to increase the VE. Also the air temperature seems to rise with about 10 degrees (celcius) higher than the ambient temperature when the engine is fully warmed (70-80 degrees) and the air box is 50 degrees. I guess this is a combination of that the intake to the air filter is pointed so that it sucks air that has blown by the engine and because the air filter is poorly cooled and placed right on top of the engine.


Now the project is to remove the engine and install the engine from my old crashed agility and get the EFI to work on that, because the rear pulley broke last friday and took a piece out of the engine block. :/


After that, the project will hopefully get exiting. I have talked with a man who wants to make bolt-on compressors for 50cc engines and i may be able to buy one from him later this summer, so i have bought an intercooler and shroud from a peugeot jetforce 125 compressor and hopefully i will get one of his 50cc superchargers (vane-type compressor).
The goal for the end of the summer is 10 hp, but it all comes down to weather or not i can get a compressor.

[baddi]

Oh.
And a partial reason why i did the convertion: Fuel economy.
Unfortunately i have been forced by the Danish police to restrict the scooter by top gearing and rpm, and the maximum speed is 38 km/h (gps). If i get above 42 km/h on a dyno, they will confiscate the scooter. :p

Also i have suffered from a dirty front brake that brakes a little all the time. The best fuel economy i could get our of the carburator with restrictions and the brake was 35 km/l (82 mpg).

With the fuel injection not in closed-loop but still with restrictions and a dirty front brake i have gotten 44 km/l (103 mpg) with AFR from 13 to 15 when warmed up.

I have also tested the AFR with the carburator and i found that it is imposible to succesfully adjust the AFR on a carburator at other points than WOT.  If yu adjust it for a good AFR at idle (12-13 is good for a carburated engine) with the air screw it will be lean at part throttle and if you adjust it for a good AFR at 10% throttle it will be rich at idle and lean at 20% throttle, so the only way to get the engine to run stable is to have it rich all over the place and then a little more rich at some points than at others. This is also because the fuel needed is not only dependent on throttle opening but also on rpm, and the methods of adjustment in a carburator is not very good at adjusting for several conditions.

With this said, the only place the AFR was stable with the carb was at WOT and above 7000 rpm. Here it was starting at AFR 11 (little rich but fine) and hitting AFR 12 when the rpm was a little above 7500 and then only slowly getting higher and higher AFR as the rpm raised, but it did not get above 14 at any point of WOT from 7000 to 9000 with a #80 jet.


Also, the GY6 engine is not very sensitive to lean mixtures. I have driven with AFR 17 non stop for an hour and not gotten higher engine temperatures than with AFR 13. The only thing i saw with a lean mixture is that it generates less power.
The only things i have found that influences the engine temp is the air temp and if the mixture is excessively rich. An excessively rich mixture carries alot of the heat out with the exhaust gas and a rise in air temp from 18 degrees to 25 degrees can easily raise the engine temp from 74 degrees to 88 degrees (personal maximum measured) if the AFR is correct.

[LoveMyKymco]

Thats awesome, Im glad it all worked out! I knew there was an air leak somewhere.

[baddi]

Thats awesome, Im glad it all worked out! I knew there was an air leak somewhere.

Yeah, i was just surprised to see the air leak coming from between pre-assembled parts.

But it works great. As long as the mixture is properly tuned, it has way better accelleration and throttle response and the fuel economy is also better.

One of the things i love about this though is that it has the sensors and models to measure, predict and calculate almost anything in the engine and with the bluetooth adapter and android app i can see it and record data on my phone which is attatched to the handlebars and it has taught me a great deal about the engine and also helped me do many calculations of the engine parameters.

[LoveMyKymco]

Its crazy how cool EFI is, especially EPROM efi.
Can you take another video of the scoot?

[baddi]

Its crazy how cool EFI is, especially EPROM efi.
Can you take another video of the scoot?

I've got a couple of videos on my youtube and can record anything you'd like besides the tuning part. That makes too long and boring videoes that takes ages to upload.
But most of the videoes are made after some changes before the tuning was fully done. :p
Anyway, it seems that the agility wont idle very stably for a long time with anything but a rich mixture, so i'll discard my manually tuned calibrations and properly test the self-tuning option that it can do with a wideband lambda sensor. Tuning the mixture is fun as long at it makes sense.

Also, i should be getting an oil cooler in the mail in one of the next days.

My youtube channel.

[MotoRandy123]

My Yager "hangs" on decel at around 4000 RPM's. I think I might have an air leak too...

[baddi]

My Yager "hangs" on decel at around 4000 RPM's. I think I might have an air leak too...

I have not studied the Yager very much so i know close to nothing of it, but if it is only at decelleration, i would not think that it is an air leak as the fuel is totally cut in 4-stroke injection engines during decelleration. If it has a CVT, i would think that 4000 rpm is then what your torque spring makes it down to when it gears down and a tighter spring would raise the rpm. If your engine does not have CVT but it hangs at 4000 rpm during decelleration, i would look at the TPS sensor as the fuel will not be cut if the TPS sensor does not read 0% (+/- 0,18%).

If you also have high idle rpm, i would look at both the TPS sensor and look for any air leaks as air leaks would reduce the pumping losses and give slower decelleration even if the fuel is cut off but then would give high or oscillating RPM when the fuel is given back at idle.

[MotoRandy123]

Hmm you might be right about the TPS. I was trying to reset the oil minder light
a couple of weeks ago and it flashed a TPS problem. Maybe I need to reset it.
Thanks!

[baddi]

Hmm you might be right about the TPS. I was trying to reset the oil minder light
a couple of weeks ago and it flashed a TPS problem. Maybe I need to reset it.
Thanks!

You should get a detailed service book on your bike to know how to reset the TPS sensor without frying the ECU, since those are quite expensive. On the ecotrons EFI kit the tps sensor is reset by turning the ignition on and then disconnecting the ECU with the power on. When the ECU is then reconnected, still with the power on, the TPS sensor is reset to 0%.

If the sensor is reading a voltage out of the desired range or it goes to something like 35,000% or 0,000% when at WOT, then the sensor should be manually adjusted by the adjustment screw and then reset again. If this does not fix the problem or the resistance between the legs are out of range, then the sensor should be replaced. I once accidentally fried the ECU, MAP sensor and TPS sensor all at once and it seems that when these are done for, the resistance will be very low and not change significantly or linear.

And now for a little update on my bike:

I decided to try the auto tuning, which i has so far avoided because it seemed too "robotic", but i accually enjoyed it, since it only took a single trip to get it tuned pretty much.
Whenever i changed the throttle, i could watch the AFR change from 15.6 to 14.7 and either becoming stable here or hovering around 14.6 to 14.8. It took a couple of seconds for every condition, but unfortunately, it is very difficult to get it to self-adjust at WOT and low rpm, since the rpm will quickly change.

[Mexwall]

Thanks for the update, glad you found the problem.

[Mexwall]

I have driven this for months without problems and have been tuning it manually while reading the AFR with a wideband lambda sensor even though it can do self-tuning when there are a wideband lambda sensor attatched. But anyway.

I decided to try the auto tuning, which i has so far avoided because it seemed too "robotic", but i accually enjoyed it, since it only took a single trip to get it tuned pretty much.
Whenever i changed the throttle, i could watch the AFR change from 15.6 to 14.7 and either becoming stable here or hovering around 14.6 to 14.8. It took a couple of seconds for every condition, but unfortunately, it is very difficult to get it to self-adjust at WOT and low rpm, since the rpm will quickly change.

Did you use the ALM from Ecotrons for this or something else?

Any luck on finding an 139QMA-A cylinderhead?

Is it already superchargerd 

[BettinANDlosing]

I bought the ecotrons kit, wrote horrible quality. Not worthy the money at all. Super cheap China product for top dollar. Warning DON'T BUY ECOTRONS!!!!!!!!! mine ended up coming out of the box with a cracked fuel injection mounting bung on the throttle body, a bad ecu, and a fuel pump that couldn't keep up with demands. Sure the principals behind fuel injection is nice in theory, but if you can't trust your fuel injection to get you out of town then what's the point? Also is your agility 2t? The agility in us is 4t. Also if you're law requires to be below 38kph why the hell after you spending so much money of the bike?