A theory involving the Hawk dlx

[ricsha91]

As we all know, the hawk dlx ecu has not been hacked to install different tunes for mods done to the bike.

The issue I see is the system not delivering enough fuel to a modified head, exhaust, or air breather.

So my question is instead of missing around with the logic of the ecu, can installing a bigger fuel injector be used versus missing with the ecu logic?

Not sure if the manufactures make a bigger injector that could be used on the hawk and also not sure if fuel pressure regulator is adjustable for a bigger injector due the pressure drop that the system would see if using a bigger injector.

I have a brand new dlx and pulled the convertor out of the exhaust and installed an KN air filter so it could breath. With around 130 miles on the bike I pulled out the plug to see what it looked like. Instead of being a nice tan color which I wanted to see, the plug was an off white color.

If anyone has some advice on knowing if this would work or not let me know

[wheelbender6]

If you can install bigger fuel nozzles, that may help. Its a gamble.

[Bill Hilly]

Unless someone has already tried the mention mods on one, and had poor results, I would bet that the airflow ,and oxygen sensors would do their jobs,and tell the computer how much fuel to spray. The injector probably has the ability to spray more fuel than you would ever need. If folks are not already trying it, I'm sure they will be soon, and much more fact based info will be available.

[franque]

@ricsha91 I've left you a reply at the bottom, just trying to correct a couple of things for some misinformed posting below

@wheelbender6 at least with the smaller stuff, one doesn't install nozzles, the whole injector is replaced.

@Billy Hilly Did you read OP's post? They had poor results! Your speculation on how fuel injection works, or should work, is disconnected from reality. In particular, this is something that is, if I remember correctly, 50 state street legal and CARB approved. I'll unpack this below. Remember, try to make what you post fact based, and not based on your opinion of how EFI might work.

- Firstly, with regards to what you said about the computer: to attain EPA/CARB approval, ECUs are quite locked down, and they are forced to stay within certain parameters. That is why, for example, a Harley that gets a different air cleaner and pipes requires a tuner so that it can run properly, and not excessively lean (OP, sound familiar?). There have been a couple of injected bikes on the market with user adjustable ECMs, but I don't think there has been anything sold in the last 10 years like that. It was a loophole that was closed.

- Secondly, the injector. Many injectors are specc'd for their specific application (though in this case, my educated guess is that they used something that was close, I doubt they received a custom injector) and there is not much room for increased fuel flow or power. Many "stage 1" tunes for cars are based on not exceeding the duty cycle of the injector, so that the car can run reliably without having to change much in the way of components. Exceeding a "stage 1" tune usually requires swapping injectors, etc. to deal with increased duty cycle on the OE injectors.

Without looking at the maps on this ECM, we cannot know the injector duty cycle, so it is foolish to say that the injector can "spray more fuel than you would ever need". That is merely a guess, and based on the wool between your ears.

- Fuel supply system - we have no idea if, or how much excess capacity the fuel pump has for this application, it could be that this system is based on European market 125s, where fuel injection is now required for emissions standards. If that is the case, which my educated guess is that Lifan didn't custom spec something for their 200cc bike, then there probably isn't much headroom for that, which I admit is (educated) speculation.

What you're describing in terms of EFI is kind of, almost, how a wide band O2 EFI system works, but only if there were no emissions regulations so that the ECM was free to make whatever power it liked, though there are still a lot of things to consider. Is the O2 sensor actually wide band? My guess, again educated, is that they're using narrow band O2 (nbO2) sensors, because they're cheaper, most name brand motorcycle manufacturers aren't using wide band O2 (wbO2) sensors because of cost. Additionally, in the locked-down state that this ECM has, there is no sense in putting an expensive sensor in it from the OE's perspective.

Why is wbO2 vs nbO2 important? A wbO2 can measure between 12-22:1 AFR, while an nbO2 can only measure 14-15:1. If the increased airflow is causing it to go leaner than 15:1, when it was almost definitely designed to run at 14.7:1, aka stoichiometric, there is not too much headroom for the O2 sensor to add fuel to get it back to 14.7, especially since anything richer than 14:1 is outside of the capacity of an nbO2 sensor to read, so they target 14.7:1, which is the ideal air-fuel ratio for emissions in a spark ignition gasoline engine.

Is it a MAP or a MAF sensor? That can change certain parameters. Additionally, there are tricks to get more fuel into the engine by spoofing the temperature sensor. Is it alpha-N, where you only have a TPS and engine rpm controlling fueling?

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My educated guess is that it is a cheap Delphi open loop nbO2 EFI system that will require either another ECM for more independent control of the EFI, or potentially a tuner for another Delphi application could be used to adjust some parameters. Realistically, without a wbO2 system, there won't be a lot of capacity for increased power, partially because peak afr for a gasoline engine is around 12.5:1.

Sorry if I was a bit long-winded, I could explain more, but I hope that this will suffice at this time.

[Deckard_Cain]

Franque pretty much hit the science on this one, but just slapping a bigger injector in there is not realistically going to work, given how EFI systems operate.

A larger injector is something you'd do along with an upgraded fuel pump to wrap up considerable other changes/upgrades.

What we really need is to extract the fuel maps and look at how the OE ECU is tuned before we can tell what is and isn't.

If it were that important to me (it's not), I'd just put together a Microsquirt ECU system and run my own programs.

[Bill Hilly]

I had miss read the first post. I read it as the plug was tan, which he wanted to see. A plug that's off white ,with 130 miles on the bike total, and assuming that some were put on before the mods is not necessarily a sign of running too lean, especially with fuel injection. I have no experience with fuel injection on motorcycle, and little on my cars,and trucks, because they are basically trouble free. I recently changed plugs on my truck with 80,000 miles, and they were all what one could call off white. They were not the super clean bright white that screams LEAN, but just a very subtle ,more greyish than tan color. I still don't know if the bike actually ran bad,(unless I'm reading it wrong), or if the plug just wasn't as tan as expected. Ideally it would be nice for the original poster to know how the plug looks on an unmodified efi Hawk after being ran for such a short time. Like I say, I have no experience with repair, or modification of any fuel injection, but I know they all have to have the ability to analyze how much fuel to spray under every changing conditions. I would think air temp ,and altitude changes would require the efi system to be flexible enough to work with slight airflow mods, but it is just speculation .

[TxTaoRider]

I'm not a fuel injection specialist so go ahead and tell me I'm way off. Lol
Back in the 90s I had a tbi transam. I had added headers an free flow cat converter and a small cam and Holley tbi body. There wasn't much available for the tbi card but the Holley had an adjustable fuel pressure regulator. By adding pressure I was able to overcome some of the WOT leaness. I did later use larger injectors and lower pressure. I'm sure it wasn't right, but it seamed to work.

[franque]

Yeah, TBI systems were incredibly cheaply designed and not very good... at least not much of a step up from a Q-jet. It was basically a carburetor by design, one big, central injector, and I know there was some semblance of computer control over it, but not very much.

It was alpha-N, which in my opinion isn't really a step up from a carb, actually a step down since it's spraying fuel based on fuel position and RPM, so it isn't sucking the fuel that it needs like in a properly jetted carb, it's just getting fuel thrown in regardless of load. The FI used in American cars was super primitive, and the kits to swap back to a carb were, aside from an emissions standpoint, with a good carb and good jetting actually an upgrade in fueling.

This is one of those things where if it is in fact a Delphi injection, there will be a workaround to be able to tune it.

[ricsha91]

Originally Posted by Bill Hilly

I had miss read the first post. I read it as the plug was tan, which he wanted to see. A plug that's off white ,with 130 miles on the bike total, and assuming that some were put on before the mods is not necessarily a sign of running too lean, especially with fuel injection. I have no experience with fuel injection on motorcycle, and little on my cars,and trucks, because they are basically trouble free. I recently changed plugs on my truck with 80,000 miles, and they were all what one could call off white. They were not the super clean bright white that screams LEAN, but just a very subtle ,more greyish than tan color. I still don't know if the bike actually ran bad,(unless I'm reading it wrong), or if the plug just wasn't as tan as expected. Ideally it would be nice for the original poster to know how the plug looks on an unmodified efi Hawk after being ran for such a short time. Like I say, I have no experience with repair, or modification of any fuel injection, but I know they all have to have the ability to analyze how much fuel to spray under every changing conditions. I would think air temp ,and altitude changes would require the efi system to be flexible enough to work with slight airflow mods, but it is just speculation .

Your correct about not having all the miles on the plug with the mods I have done to the bike. Here is a photo of the plug after pulling it with about 30 miles on the plug after the mods. I did clean the plug up before the mods to see results if I would be running lean.

Not the best pic due to having to shrink the photo down to meet the requirements to fit the data size for the jpeg.

[Bill Hilly]

Originally Posted by ricsha91

Your correct about not having all the miles on the plug with the mods I have done to the bike. Here is a photo of the plug after pulling it with about 30 miles on the plug after the mods. I did clean the plug up before the mods to see results if I would be running lean.

Not the best pic due to having to shrink the photo down to meet the requirements to fit the data size for the jpeg.

That does look like it's running lean to me ,from the picture it looks pure white. Did you notice it running any differently after the mods?

[ricsha91]

Originally Posted by Bill Hilly

That does look like it's running lean to me ,from the picture it looks pure white. Did you notice it running any differently after the mods?

Not really sure about running differently due to doing to many mods at same time.

Motor still runs fine, but between doing the delete on the convertor, k&N air fliter and changed the sprocket to the 17, 45 there is no ass left from the motor in 5 gear. I was running a 16, 45 before deleting the convertor, but never did have a gps speedo on the phone to see what the true speed was.

Yesterday took the bike out with the speedo on the phone with mods and was only seeing mid 50's on average. Saw mid 40's going into a strong head wind (gusting mid 20's) and top speed of 60 with wind.

I wish I would of got more data before doing the catalyst removal. The other two I can change back.

[Bill Hilly]

I really don't know. 30 miles is not a lot. Maybe you could hook your original air box back up, and see if it makes any difference in how the plug looks. From the picture it does look pretty white, but I'm looking at it with my phone. It does look like it has a little carbon on the recesses. I would try another 30 miles with the air box hooked back, and look at the plug, because I don't figure you want to weld the cat back in unless you absolutely have to. After doing that, and you are in doubt about the bike running too lean, I would consider welding it back , because it may eventually burn a valve is ran way too lean .

[ricsha91]

Originally Posted by Bill Hilly

I really don't know. 30 miles is not a lot. Maybe you could hook your original air box back up, and see if it makes any difference in how the plug looks. From the picture it does look pretty white, but I'm looking at it with my phone. It does look like it has a little carbon on the recesses. I would try another 30 miles with the air box hooked back, and look at the plug, because I don't figure you want to weld the cat back in unless you absolutely have to. After doing that, and you are in doubt about the bike running too lean, I would consider welding it back , because it may eventually burn a valve is ran way too lean .

Ummmmm, yep a little to late with the cat. I ended up cutting the pipe in half and drilling out the cat and then welding the exhaust pipe back up. So that is a no go with the cat. I will ride it for another hundred or so and take another look at the plug and determine where to go after that.

I really wish it could be as simple as just putting a larger injector in place of the oem injector to make up the difference in the fuel shortge the ecu is giving the bike. I know the ecu is looking at all of the parameters (air temp, air density, rpm, throttle position, 02 sensor) and sending a signal to the injector to pulse open for a certain duration to meet and make the perfect stoichiometric. I just figured if the ecu is at its max bandwith for the pulse to the injector, why not just install a bigger injector to get the needed fuel to the cyclinder.

[JohnC]

Originally Posted by ricsha91

Ummmmm, yep a little to late with the cat. I ended up cutting the pipe in half and drilling out the cat and then welding the exhaust pipe back up. So that is a no go with the cat. I will ride it for another hundred or so and take another look at the plug and determine where to go after that.

I really wish it could be as simple as just putting a larger injector in place of the oem injector to make up the difference in the fuel shortge the ecu is giving the bike. I know the ecu is looking at all of the parameters (air temp, air density, rpm, throttle position, 02 sensor) and sending a signal to the injector to pulse open for a certain duration to meet and make the perfect stoichiometric. I just figured if the ecu is at its max bandwith for the pulse to the injector, why not just install a bigger injector to get the needed fuel to the cyclinder.

Did removing the CAT change the sound or volume of your exhaust?



Thanks,
John

[ricsha91]

Originally Posted by JohnC

Did removing the CAT change the sound or volume of your exhaust?



Thanks,
John

At idle not much difference in sound, but going down the road yes ( by a lot).

Also the bike can breath. After removing the catalyst the amount of air being pushed out of the exhaust at idle is quite noticeable.