Parallel resistor mod?

Well, it's not really that rich, and the mix comes down quickly as the engine warms, but if I get the other end of the temp range rich enough (well almost rich enough, as I've never really had it rich enough to eliminate all pinging) then it's always too rich when the weather/engine is cool.

I think the rate at which the ATS richens the mix as the air cools is too quick, and adding the parallel resistor will flatten that rate somewhat. That will hopefully make the response of the TFI more appropriate.

As an aside, I put the TFI on my bike before I did the pipes or the intake mods. It did make the bike run better. Not much more power, but less pinging. The response to temp changes was less skewed then than after I changed the pipes and intake. Now I have more power, but the response to temp changes isn't as appropriate.

[blowndodge]

And mine is too slow. My bike now starts and runs real well in the cooler weather. Warmer weather is the killer in engine performance and ping. Although the resistor and coolant change as made headway, I'm still looking for hot weather total elimination of pinging. Either a stouter ATS resistor or WTS resistor in tandom. Carry on CD. Tell me how you wired "parallel" as I'm a little lost as to what your going to do besides run a second wire from the ECM. Seems to me electricity would follow the path of least resistance, but I'm no electrician!!

[dogdoc]

HUH

[blowndodge]

C'mon doc join in. Whats the ?

Well, again: The TFI can't subtract fuel. I'm doing the reverse of what you did with the resistor, to subtract fuel. Then I'll add it back with the TFI where I need it most.

When you add a resistor in series to the ATS, you simply add that resistance to the resistance of the ATS, and that's what the ECU sees. That's what you did.

Adding a resistor in parallel (across the two leads of the ATS) partly short circuits the ATS. I'll use a high value resistor so it's not like a direct short, but the object is to make the ECU think the sensor is hotter than it is. It will cut back fuel across the board, but it will cut it back less in the hottest ranges. When I add fuel back with the TFI, I'm hoping it'll add proportionally to balance out the mix across the entire temp range.

I don't know how to describe it better than that, so I'm just going to have to test it out and report back what happens. ;)

[bobzinger]

Please feel free to correct me if I'm missing something.
The TFI adds fuel in only a few specific areas.
1. (Idle Jet) 2500RPM and below.
2. Main Jet) above 2500.
3. accelerator pump?

Doesn't the Power commander add or subtract fuel at a 198 or so points. This map is for a 2005 1600 Nomad with V&H Baggers and an Upgraded Air Cleaner.

[blowndodge]

A Power Commander does what you stated.

I know what your doing cad. report back with results. when I do the WTS mod I'll report back as well. good luck!! Hope that opens up a new window of options for us Nomad owners..

Originally Posted by bobzinger

Please feel free to correct me if I'm missing something.
The TFI adds fuel in only a few specific areas.
1. (Idle Jet) 2500RPM and below.
2. Main Jet) above 2500.
3. accelerator pump?

Doesn't the Power commander add or subtract fuel at a 198 or so points. This map is for a 2005 1600 Nomad with V&H Baggers and an Upgraded Air Cleaner.

This is what I gather from my conversations with Mark at Dobeck:

Actually, that Power Commander map is only part of the story. In between those points the PC interpolates values, so you get a smooth surface in all directions. It literally replaces the map coming out of the ECU with its own map.

The TFI Doesn't exactly work by "mapping" any specific values to the F.I. It reads what the ECU is sending to the injectors and just adds to that based on it's it's internal algorithm, as modified by how you've set the first pot. So it's effect is spread over the entire range of RPM and fuel requirements smoothly, in except that it will provide a surge like an accelerator pump when it senses the ECU doing that as well. How much it adds to that surge depends on the second pot.

The third pot determines the fuel added in the upper RPM bands, and the point where it takes over from the first pot's adjustment is determined by the setting of the 4th pot. On a Nomad that 4th pot is set to 4500 RPM, and the third typically set to "off" so the effect of the first pot fades off by 4500, and then and no more fuel is added.

The other thing Mark mentioned is that the Vulcan injection works somewhat differently from most other bikes in this respect.

On most bikes, when the ECU wants to send more fuel, it holds the injectors open longer on each pulse. They pulse on every intake cycle. The longer they're "on" the more fuel is delivered.

On the Vulcan, the pulses are all the same length, but when the ECU wants to send more fuel it triggers more pulses. By counting the frequency of these pulses, the TFI knows what the ECU is trying to do, and determines what it is to do based on that.

I hope I explained that clearly, and that I understood Mark clearly. My conversation with him did not actually proceed from point a to point b in a linear fashion. It kinda jumped all over the map.