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Discussion Starter · #1 · (Edited)
Ok so my wifes 848 is still showing issues. The bike runs smooth while rolling on the throttle, but hesitate/stutters at cinstant throttle. I replaced the following and it improved initially after adding new coils, but the problem is back.

I have replaced:

Fuel filter
chain
front sprocket
rear sprocket
ecu
ignition coils
spark plugs
battery

I have checked

Tps signal voltage and compared to jp diag readout
fuel pump relay
all grounds and connectors
Kick stand sensor

I have reset tps.

I initially pulled a primary/secondary ignition circuit on coil a fault. Now this is gone. Should i replace the tps next?

Would a bad voltage regulstor cause this?

Could the dp ecu be that out of tune?
 

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Bad voltage regulator… thats where I'd be headed next. You can completely unplug it and ride the bike a short distance to see what it does as it will drain the battery. If it has the same problem, then its not the regulator, but it's worth the test!
 

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Discussion Starter · #3 ·
Tuned ill try that as soon as i get home
 

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Discussion Starter · #4 ·
Voltage reg was bad. I just replaced it and still have the issue. Stator is testing good.

After replacing the voltage reg is keep pulling the following faults.

Primary/secondary circuit a fault
primary/secondary circuit b fault
throttle position sensor circuit a fault.
 

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It's possible the TPS is arcing inside causing erratic readings to the ECU. I had a TPS with a dead spot and when you reached it, the bike fell on it's face until you go past it. As yours isn't quite doing that, it's possible its just not reading properly when on the gas.
 

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Ok, so now ya gotta check grounds. Gotta go through everything you haven't tried yet. It may still be a faulty TPS unit, thats absolutely a possibility. However, when diagnosing it's important to have a direct correlation to that issue, rather then a whole host of other issues like you have right now.

Also!!! Do you have any aftermarket electronics on the bike? If so, remove all of it for testing purposes.
 

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Discussion Starter · #7 ·
No aftermarket electronics, wxcept for the hid ballast.

I dont know what other grounds to check. Ive checked the grounds coming off the battery terminal. The one to the ecu and the one to the starter motor.
 

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Discussion Starter · #12 ·
Not yet, I got called away on business.
 

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Discussion Starter · #14 ·
Ok Guys sorry I got called away and was not able to get to this for months.

I just replaced the VR, TPS, and Stator wires. I am having the same surging issue, but now I have found some more specifics.

If I put the bike in neutral and let it warm up then increase the RPMs and hold around 7k it will backfire bad! Like POP...POP almost like decal flame throwing on a full system if you will. Also now as the the bike chugs it will blink the check engine light, but then it goes away....
 

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You need to read the ecu and read the diagnostic codes. That will help guide you through this problem. There is something very basic your missing because you've replaced too many things. If the problem stays the same, then it must be something like the wiring harness. The ecu code reader will help give you some data on what part isn't working. Heck, it could be a pinched injector or timing sensor gap. It's something real simple and if you go back through the history of the machine, you may find a clue, prior to these current issues.
 

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Discussion Starter · #18 ·
I am tearing the bike down to start at the beginning again. The problem is there aren't any codes sticking. The CEL will flash and then go away.

The only change I can think of was the removal of the exhaust flapper motor. But the bike has a DP ECU...so that should have no effect.
 

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Long shot

This is highly unlikely, but I'll throw it out.

My 2008 848 track bike had a DP Race ECU and I installed a Shorai battery.

First lap it was clear the bike was almost unrideable. Ran fine from idle to 7000, then stumbled to 8500, then ran fine above that. Re-installed the Yuasa and she was OK again.

Next season I installed a MicroTec 197 ECU and decided to try the Shorai again. This combination worked and and she has run fine ever since.

I have absolutely no god-damned idea why this should have happened, but it did.
 

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Discussion Starter · #20 ·
Ok I am starting over....and by over I mean I took the bike apart again...remoed the entire wiring harness and am going through it wire by wire. I am also taking the engine over to a local level 3 Ducati mechanic and having him check the valve clearances and timing again in case I screwed it up somehow.

I will then reassemble...check the ECU map..and test drive. If it doesn't work after that I am going to try another set of tools that consist of a 10 lbs sledge hammer, a plasma cutter and a few blocks of M112.
 
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