Booster Plug

I think you're right Charlie, I started reading not long ago about other spoofers & one Eruption user throwing the CEL in cold weather. I don't know what the engineers were concerned about. Cat-cons not working properly & fouling maybe?

A few months ago I met Jay Leno in the local mountains by chance, he asked what I was riding, I showed him the TR & told him I have a Guzzi too. He said something about having to be a real enthusiast to ride a Moto Guzzi, but I don't think so, I think the real enthusiasts are YOU guys that ride year 'round!

The Eruption as it is follows the IAT temperature curve with a 6% offset fuel enrichment, I wouldn't want to change that just to shut a light off, but we could switch back & forth from OEM IAT to Eruption. I'll give it some thought when I'm sober.

So, maybe two IAT's in the air box, switch between the modified one and the OEM, hmmmm? By the way being sober can be overrated IMHO.

Just drill a hole and mount a standard IAT next to the Eruption and swap back to it in really cold weather

Was in the process of writing when I got interrupted, DRZCharlie beat me to it

After thinking about my statement above overnight there really isn't any point to having a second AIT that when in use would reintroduce a lean stumble. My bike had the stumble the day before I installed the Eruption Mod at 28* ambient outside temperature. Now it doesn't. The difference is the CEL light is now on after the dash temperature gauge shows zero. On my friend Mikes bike he had the same ambient outside temps but as he rode the temps slowly dropped on the dash to zero. Why, wind chill? Have the additional thermistor's somehow affected how the ECU sees and somehow recalculates the ambient temperature on the dash?

If the ECU is considering the air temp and provides the corrected calculations for enriching the fuel mixture, and, the Eruption is providing the right information for the ECU to calculate proper enriching then it would seem that the Eruption is doing what was intended.

I guess the bigger question is when the CEL is on, is there ECU sampling and subsequent calculation that is causing or would cause the engine to be harmed? If not then it seems to me that like the "flashing snowflake" the CEL can be ignored. But how is this best verified? So, back to my original question to Run-it. Can we some how mod the Eruption to provide switching between the legs of the Eruption thermistors to accommodate a lesser/lower ambient outside temperature differential and still maintain the correct enrichening on the warm up circuit and not have the CEL on?

Then again, if the light is just a default condition and causes no harm maybe a patch of electricians tape over the light on the dash? Ha

Yes, a terra. Plenty more cold weather coming for us to get more data. I am just going to keep riding, if it blows up, it will be fun doing so.

Just to clarify, the Eruption will offset the temperature 20C or 36F. It's a good idea to check the resistance values of the thermistors that your vendor shipped to you prior to the build, I have unpleasant visions of people getting a/the wrong thermistor(s) shipped. They all look the same but can have way different values, if there's a discrepancy in what your dash reads & what the outside air is, you (or anyone) can compare the modded IAT resistance/temperature values to the table in the Eruption thread.

If the dash shows a (consistent) 20C / 36F lower than actual reading - then the Eruption thermistors & build is correct & so will be the enrichment amount.

I'm thinking there is no harmful condition present when the CEL is illuminated in low ambient. The evidence we have so far is that the engine runs normally. Timing & fuel is all we have to worry about & either would show up in how the engine runs.

Can't have a 6% enrichment without spoofing the ecu into thinking it's 20C colder than it really is. You can likely make a circuit that allows for switching to a 3% / 10C offset or some other intermediate value. So this would keep the CEL off a while longer. Will 3% richening be adequate to fend off the stumbles? Don't know, but it would be better than nothing.

I ordered my thermistors from Arrow. When I did the resistance check they were spot on. After my experience this morning I felt like there was no difference in engine performance with the CEL on. As for switching out half the thermistors for 10C it would be a great experiment.

OK you did a resistance check - you know you're good then.

I think a design that switches from the Eruption's standard 20C / 6% offset to something less will take the form of a second circuit in parallel with the Eruption.

It would go something like this...

Leave the Eruption (your modded IAT) as it is.
Don't cut but just splice into one of the two wires that plug onto your modded IAT.
Add a spst switch to the end of that new wire.
Add another thermistor (or pairing of thermistors) inline (series) with your new switch. Thermistor values yet to be determined.
Run the other thermistor wire to the other IAT wire.

I can draw it out later after I have a chance to figure out what values should be used.

I have a spst switch in my electronics parts stash. I'll order a couple more thermistors after the values are determined. My problem is going to be that I can't get to this until after Christmas because I have guests coming in tomorrow then I leave for Iowa for a few days shortly after. This sounds like it might be worth a try.

Hey run-it, I have a question you may be able to clarify for me. How would adding a regular resistor work in the situation with a switch? It's not like it would be used unless it was real cold right?

What do you find that is troubling coffee? The only thing that really bugs me about a spoofer being in place is the fact that the CEL comes on once the dash ambient temp light is at zero. My concern with that is that we don't know whether there are some default systems that come into play such as sampling changes in the O2 sensors.

A resistor by itself won't be good for a wide range of temperatures, a resistor in parallel with another thermistor would be better & may be good enough - that's all the Booster Plug is.

Better yet would be if something would track the IAT R/T curve like Eruption does but instead of 20C offset did a consistent 10C or thereabout. Don't know if I'd ever use it but people like options.

Here's how the new circuit will look, B to C is the new section, A & D are already in place.

Just need to figure out a value for the new thermistor(s).

My "Eruption Spoofer" mod is working perfectly! What a huge difference, no hunting for a steady idle, no fear of the bike dieing at a stop sign or pulling away. It was 28* when I went for a ride. The Eruption Mod is supposed to fool the ECU into thinking it is 20* cooler.

Here is the evidence that it works as advertised. No CEL.



Best of all it was cheap and it works brilliantly.

Could you just use a variable resistor as the switch and resistor in that pic? A variable resistor from off to whatever resistance you want?

I'm glad I don't know anything about thermistors. If I did, I'd probably be experimenting with mine too.

All I know is..........I was sad..........I plugged in my Booster Plug..........Now I'm happy.

Yep you definitely could. That's how it was done on early spoofers. There was a temperature chart & you dialed in the resistance value that worked best with your ambient temperature. Thermistor(s), make those resistance adjustments automatically.

Nev how are you finding the WUKA?
Thinking of putting this on my TR have seen their are problems when it is cold but that shouldn't be too much of a problem in Sydney..