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Enduro Engine 4 stroke (including EFI & Exhaust) 4 stroke engine, EFI, and exhaust discussion


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  #11  
Old 11-03-2009, 03:07 AM
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I've just come across a product called TFI from Dobeck or Techlusion. It sits between the injector and ECU and allows you to amend the fuel delivery as you would with a carb system. This looks a better alternative to messing with trim and idle speed on the main ECU.
http://www.dobeckperformance.com/

This functionality should be built in as standard for competition bikes.


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  #12  
Old 11-03-2009, 07:01 AM
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I had one on my HD VRod. All it is is a pulse stretcher device, extending the injector pulse width based on some small potentiometer adjustments. There is a newer all digital version as well. They work OK, but are no where near as precise as changing the map. The adjustments are limited to three RPM ranges, so you wind up being rich in adjacent areas of the map to the area you are trying to correct. Also, you can only increase pulse width (add fuel).

What is your problem? If its an idle issue you will be much better off adjusting the trim and air bleed. For what you pay for the TFI you can have the Technoresearch VDST, and do your trim, TPS reset, and diagnostics. If the base map is OK then the TFI is a waste and just adds complexity. The TFI is mainly used as a quick way for adding fuel when an aftermarket exhaust is used on a modern street bike, as they are set lean anyway from the factory for emmisions reasons.
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Old 11-03-2009, 08:36 AM
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Originally Posted by GMP View Post
I had one on my HD VRod. All it is is a pulse stretcher device, extending the injector pulse width based on some small potentiometer adjustments. There is a newer all digital version as well. They work OK, but are no where near as precise as changing the map. The adjustments are limited to three RPM ranges, so you wind up being rich in adjacent areas of the map to the area you are trying to correct. Also, you can only increase pulse width (add fuel).

What is your problem? If its an idle issue you will be much better off adjusting the trim and air bleed. For what you pay for the TFI you can have the Technoresearch VDST, and do your trim, TPS reset, and diagnostics. If the base map is OK then the TFI is a waste and just adds complexity. The TFI is mainly used as a quick way for adding fuel when an aftermarket exhaust is used on a modern street bike, as they are set lean anyway from the factory for emmisions reasons.
I want to adjust the idle and I want it to start easier.
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Old 11-03-2009, 09:22 AM
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Then get the VDST, adjust trim and air bleed screw. The TFI is useless for this.
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Old 11-03-2009, 09:52 AM
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Then get the VDST, adjust trim and air bleed screw. The TFI is useless for this.
The dealer who has quite a bit of experience with GG and also Ducati (who use Magneti) couldn't get it any better. Said there was limited scope on the GG ECU. The TFI expands the adjustment quite a bit, even if only richer. Also someone else I know had similar problems on a Quad and it couldn't get sorted until a TFI was added. He reports it now starts easy in any condition and even pulled a bit better, not that I have a problem with that.

Not saying I'm getting a TFI but it sounds attractive from where I'm sitting. Buying the VSDTS could be an expensive test. Why would I do better than the dealer?
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Old 11-03-2009, 11:58 AM
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If the problem is a lean area of the map, the TFI can help. I cannot see how it could improve starting, because it is bypassed and not functioning when the bike first starts. It takes a few seconds to boot before it does its thing. This is because the ECU is applying a heavy start enrichment factor of its own at his point. There is a yellow LED that flashes while this is happening. Once this is complete, it will enrich the idle if the low speed range adjustment is set above zero. I'm sure mine worked this way, but if by chance Dobeck made a design change maybe you should call and find out.

The ECU trim parameter is fixed pulse width change, that is it adds or subtracts (on my IAW-5AM) approx 13us for each number change. It is not a % change of width, thats why its effect is primarily at idle and low demand areas of the map, where the pulse width is more narrow (leaner).

In the USA, the VDSTS, or VDST Standard (for one ECU family) is $200. A TFI is around $250+.

I assume your TPS was checked/reset and no codes are present. I'm by no means an experienced FSE guy, but I'm comfy with EFI systrems. I don't recall anyone here having to resort to adding a TFI to get the bike to run right, once the race map was enabled in the ECU.
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  #17  
Old 11-03-2009, 03:25 PM
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You may be able to do better with the VDST software than the dealer because you wont be paying by the hour and will have the abilty (albeit limited) to play around with the fuel load setting and see if you can get a solution that suits you. You will also be able to spend time checking the interpreted sensor readings against actual conditions to see if there are any anomalies there.

What vintage is the FSE? I am sure its on here somewhere but I cant find it.
What idle rpm do you get and what were you looking to get?
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  #18  
Old 11-03-2009, 04:05 PM
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GMP: Why can't the TFI work immediately? It'll boot when you turn the power on. It's not running Windows, it should be initialised as fast as the ECU! Maybe it doesn't work straight away for some reason but there's no reason it couldn't work from 0 revs.

The advantage over VSDTS trim that the TFI appears to have is there are separate settings for idle, acceleration and wide open.

Incidentally the bike runs fine but it doesn't like starting. From cold it will crank forever on a closed throttle with absolutely no sign of life. I have to play a game where I open the throttle, start cranking, let the throttle close and if it catches keep it cranking for a while or it'll die again. On the kickstart I have only once managed to start it and it took a lot of kicking leaning against a tree. I'm assuming it's too lean to start but that is an assumption not proven fact.

It's a 2006 model by the way and I take the point about having more time than the dealer.
I took it to him and asked for the valve clearances to be checked and the fuel trimmed. He did that and gave me the settings before and after having richened it a little but admitted it wouldn't start any easier. The only noticeable difference is it takes longer to warm up.
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  #19  
Old 11-03-2009, 08:55 PM
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Read my post again.

How the ECU works during starting is to continue to increase the enrichment factor (fuel) while cranking if the bike does not fire. I would look into the throttle angle, air bleed, TPS, and check the codes. If the ECU is one that allows trim adjustment, and it is, (open loop, non-emmisions) you should be able to trim it up and down to the point of it stalling from being too rich/lean. I have done this on my Ducati with the open loop race ECU.

One thing I forgot, does that system have an idle air compensation stepper motor valve? I'm too lazy now to look it up myself.
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  #20  
Old 11-04-2009, 07:03 AM
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Quote:
Originally Posted by GMP View Post
Read my post again.
I have and it's still not clear! Are you stating fact that the TFI does not change the pulse at startup or making an assumption? There is no reason why the TFI could not operate at 0 revs but I have no idea if it actually does. Let's put that question on the shelf unless we have a definitive answer from measuring or TFI themselves.

Quote:
Originally Posted by GMP View Post
How the ECU works during starting is to continue to increase the enrichment factor (fuel) while cranking if the bike does not fire. I would look into the throttle angle, air bleed, TPS, and check the codes. If the ECU is one that allows trim adjustment, and it is, (open loop, non-emmisions) you should be able to trim it up and down to the point of it stalling from being too rich/lean. I have done this on my Ducati with the open loop race ECU.

One thing I forgot, does that system have an idle air compensation stepper motor valve? I'm too lazy now to look it up myself.
Well if it is supposed to keep enrichening until it fires something is broke on mine and I suspect many others. There is no air compensation stepper on the circuit diagram. What do you suspect - not enough air?

I'm going to try connecting a car battery to test if it spins any faster - was also wondering if the little battery can't supply enough cranking amps. It does seem quite slow turning.
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