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Suddenly dying at 2000 rpm


Chuck

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I hate it when I don't understand what is happening. I just finished going through the Mighty Scura. Most of the tank off check list, plus one of Scud's nice fuel lines, and a new fuel line from the right injector to the PRV. I had to remove that fitting from the injector so I wouldn't break something, but that is the only thing I changed over there.. oh.. unplugged the injector and TPS.

Finished everything up, pushed it out in the hanger, and it started right up and did it's lumpy idle thing. :)

Started to ride it up to the Guzzi Garage, and it stopped dead as soon as I gave it some throttle. Hmmm. Tried it again. Same thing. As soon as it went to 2000 rpm, it died dead as a mackerel. I've *never* heard of this before. Yeah, it's repeatable.

Hooked up Guzzidag, and looked for faults. Nada. Hooked up my tester to the TPS, and it wasn't where I set it last. Not terribly far off, though. It was about 175 mv. Moved the throttle a little off idle, and the tester said OL.

Can someone explain this to me? I'm *assuming* the TPS suddenly magically went bad?

TIA..

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To confirm you had loosened the TPS to test it? It’s very sensitive when you retighten it.

 

 

Sent from my iPhone using Tapatalk

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I've been through 3 TPS on my EV,  some days it will still cough through throttle range.  Some days it will be smooth as glass.

 

Most days it will do both.

 

I would only mess with it when Docc does his voodoo dance.  That california cycle works sells aftermarket TPS.  They're about $80.  Doesn't include the voodoo dance.  

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To confirm you had loosened the TPS to test it? It’s very sensitive when you retighten it.

 

 

Sent from my iPhone using Tapatalk

Didn't touch it. I'm familiar with how fussy setting it is.

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Ok, it's *not* the TPS. What I was seeing was simply overtravel of the meter set on mv. Setting it on DC volts, it travels very smoothly from .150 to 4.75 volts.

What else can cause the engine to suddenly stop running at 2000 rpm??

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Does it stop above 2000 rpm when it is in neutral too?

It won't go above 2000. Acts perfectly normally untill 2000 and instantly dies. In my recollection, I've never heard of this one.

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I'm not Kiwi_Roy, but I wonder if the problem comes from an intermittent connection in the circuit from the neutral switch, sidestand relay (#3), run switch, ecu relay (#4)? I had some relay base sockets pushed back which made intermittent contact at awkward moments.

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Have you done anything with the timing sensor? It’s easy to pull, maybe there is a bit of schumtz on it?

 

Is it acting lean? Rich? Pull a plug after it dies and see what it tells you.

 

I’ve got a couple TPS sensors I could send your way if you want to check that out.

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Have you done anything with the timing sensor? It’s easy to pull, maybe there is a bit of schumtz on it?

 

Is it acting lean? Rich? Pull a plug after it dies and see what it tells you.

 

I’ve got a couple TPS sensors I could send your way if you want to check that out.

 

That was one of the things that was on the tank off list. It was weeping, so I pulled it, cleaned it, and put some hi temp silicone around the o ring and reinstalled it. I know they are fragile, and maybe a wire broke, but the test at the computer plug looks ok. 703 ohms instead of 680 sounds ok to me.

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Sounds more like fuel to me Chuck. I had a Ducati do this to me once due to a lean chip in the ecu. I had modified the engine for racing and installed a different chip that was too lean. It was all good when the engine was cold and on the enrichening map and idle and reving in neutral was fine when warm but as soon as you opened the throttle under load when riding and it called for genuine fuel flow it stopped dead as well. No missing or hicupping, just stopped. 

I'd re check all the fuel stuff you pulled and also whether any of the hoses has collapsed internally. Have a look at the fuel pressure when it happens.

I only mention it because it feels for the world like ignition when they stop dead like this but it can still be fuel and thats what you've had apart. 

 

Ciao

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Have you done anything with the timing sensor? It’s easy to pull, maybe there is a bit of schumtz on it?

 

Is it acting lean? Rich? Pull a plug after it dies and see what it tells you.

 

I’ve got a couple TPS sensors I could send your way if you want to check that out.

That was one of the things that was on the tank off list. It was weeping, so I pulled it, cleaned it, and put some hi temp silicone around the o ring and reinstalled it. I know they are fragile, and maybe a wire broke, but the test at the computer plug looks ok. 703 ohms instead of 680 sounds ok to me.

 

Would checking the resistance of the coil tell you if the sensor is reading correct? Like if the gap is incorrect.

 

I ask because I’m curious, not trying to be facetious. Also not trying to rhyme...

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