Author Topic: Tickle the temp sensor  (Read 2112 times)

MotoRandy123

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Tickle the temp sensor
« on: October 16, 2012, 05:58:52 PM »
The Yager uses fuel injection so you need an expensive setup to tune it.

A quick and easy $5 mod is to trick it into thinking the air is cooler that it really is.

This is the way those gain 20 HP and get better fuel economy gimmicks work.

The problem is the temp sensor has unequal changes at hot vs cold. It reads
15000 at -20c, 2500 at 20c and 580 at 60c so a fixed resistor won't work at hot and cold.

That's where the NTC thermister comes in. It acts exactly as the stocker so has big
changes when cold and small when hot. You can buy the EPCOS NTC thermister on ebay here;

http://www.ebay.com/itm/5-EPCOS-Precision-NTC-Thermistor-Fast-Response-w-BONUS-TINY-Fit-anywhere-/230720029512?pt=LH_DefaultDomain_0&hash=item35b7fc4348

Then solder it inline with the temp pin on the TMAP. This will double the temp the bike sees.
The bike will run richer and advance the timing for better part throttle response.

Too cold here for me to try it but it has worked for me on other FI bikes!
2012 Yager GT 200I - Southern NH

old geezer

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Re: Tickle the temp sensor
« Reply #1 on: October 16, 2012, 06:10:10 PM »
Not something I would do to any fi vehicle and I am an old time hot-rodder.

The proper way would be to find out if the engine control module can be programmed.
« Last Edit: October 16, 2012, 06:12:57 PM by old geezer »

CROSSBOLT

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Re: Tickle the temp sensor
« Reply #2 on: October 17, 2012, 07:44:11 PM »
I agree with The Old Geezer about reprogramming. However, (here it comes....) fiddling with the temp sensor is a really CHEAP way IF ya got the time to test ride your changes. Me, I rather ride than test ride. I'm a geezer, too, and I may not have all that much time left......(start the violins)

Karl
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

fshfindr

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Re: Tickle the temp sensor
« Reply #3 on: October 17, 2012, 08:50:52 PM »
That makes 3 of us geezers.

Richard L.  :)
Richard L. in Bellmawr
Keep The Rubber Side Down & The Helmet Side Up

old geezer

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Re: Tickle the temp sensor
« Reply #4 on: October 17, 2012, 09:33:19 PM »
I agree with The Old Geezer about reprogramming. However, (here it comes....) fiddling with the temp sensor is a really CHEAP way IF ya got the time to test ride your changes. Me, I rather ride than test ride. I'm a geezer, too, and I may not have all that much time left......(start the violins)

Karl

Fiddling with the temp sensor can cause it to stay in open loop. Not good.

MotoRandy123

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Re: Tickle the temp sensor
« Reply #5 on: October 18, 2012, 10:27:54 PM »
Do you know it is ever in open loop?

The ECU will see the water and engine temp warm up then stop the cold enrichment.
It's only the air temp that it will see wrong. This will only give you 5% richness. The
ECU is still in control using it's extensive map to control things.


Check out this article to see a successful implementation of this. He use a fixed resistor.

http://autospeed.com/cms/A_112726/article.html

They sell the booster plug for $150 to the BMW guys. It's the same as this NTC.
http://www.boosterplug.com/shop/cms-21.html
« Last Edit: October 18, 2012, 10:30:39 PM by MotoRandy123 »
2012 Yager GT 200I - Southern NH

MotoRandy123

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Re: Tickle the temp sensor
« Reply #6 on: October 19, 2012, 07:45:24 PM »
Taking a look today I found the TMAP says made in Germany on it.
(TMAP = Temperature Manifold Air Pressure)

I wonder if the fuel injection system comes from Bosch?
2012 Yager GT 200I - Southern NH

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