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Discussion Starter #1
Well, it's been a while, but the winter rides kept the engine temperatures low (<175F), but my last ride in 80F+ degree weather has ressurrected the engine caughing problems of last summer. After a longer ride, I had my wife hop on fro a short run around the parking lot of a park, and the caughing returned in spades! Basically, the hotter the engine gets the worse the problem.
I'm sure this has something to do with a temp. sensor. Several threads on other Duc machines support the theory.
My question for you guys is, where are the sensors, how many are there, and which is the likely culprit? The temperature gauge seems to indicate correctly, so is there another which might be bad??
 

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Life is too short to worry !
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You might also consider the coils or spark plugs (The easiest to check as a new set would resolve the issue - you could even try a colder running plug).
Either of these might misbehave at higher temperatures if faulty.

Is it firing badly on 1 or both cylinders , if one only then you could try switching the coils.
 

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Temps sensors for the water temp are on the left side of the engine in the coolant fittings for each head. You’ll see them as there will be an electrical connection going to it as well as a small water hose. One is for the temp gage; the other sends the temp data to the ECU so it can adjust the fuel map accordingly.

There is an air temp sensor as well as an air pressure sensor. Both are under the head light fairing, I think... Both input to the ECU for fuel corrections, but I am not sure if the impact is as much as the water temp. Could be, not sure. You just don't hear of them going bad very often.

You could try swapping the water temp sensors, a little messy to do it, but it will tell you a lot if your dash temp reading is suddenly screwy.

Electrical, could be. High temps can effect things like coils and plug wires if they are in poor condition. Insulation brakes down and heat can make the problem worse.
 

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Mr Leakered
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Check out the ducatidiag thread. It will let you see the sensor readings and allow you to run ignition tests. All for just the cost of the cables and a donation if you feel like it.

Have a good one.
 

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Discussion Starter #5
Thanks all for the comments. I'll try swapping the sensors first; sounds like the low $$ approach, and I should have time tomorrow. Easy fix, if not too messy. I'll report back!
 

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You could try swapping the water temp sensors, a little messy to do it, but it will tell you a lot if your dash temp reading is suddenly screwy.
You can do this simply by swapping the wires between the sensors, there is enough length and there is no coolant loss.
 

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Discussion Starter #7
Derek,
That was exactly what I was hoping to do; I haven't gotten the fairings off yet to verify the lead lengths, so yours was a timely reply. I plan on doing it later, if sheet-rock work doesn't get in the way! I plan on riding a distance Tuesday. Will report back...
 

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Discussion Starter #8
Well, now I know one thing its not! I got the engine up to temp., and swapped the cables (horizontal is the gauge sensor, while vertical is the ecu sensor...). When I pulled the vertical cable, the engine immediately adjusted rpm downward. I hooked up the gauge to that sensor, and got the same reading as with the horizontal sensor.
I took it for a quick ride at higher engine temps (185-190), just to make sure it wasn't a loose wire, and got the same backfiring/sputtering as usual.
I guess its on to coils and plugs?! Never had those go bad though.
 

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Leave the plug for the ECU unplugged and take it for a ride that way. The ECU will think the engine is cold, and it will richen up the mixture.

If the stumble goes away, then try plugging in a 220 Ohm resistor into the ECU plug. It will then think it's a rock-solid 207 F, and should run well also.

One note about doing this is the fact that the ECU also controls the fan relay. So doing either of these, just be sure to drive it so that you get enough wind thru the radiator to give normal cooling.

The Jaeger sensors are a known weak point. Search in here for "BOSCH" and you'll find many strings related to this, along with the Bosch p/n's and also NAPA equivalents.
 
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