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Engine dying when coming to a stop


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OK I moved this to a new thread so I wouldn't hijack some else's.ūüėź¬† To recap my VFR was dying most of the time whenever I came to a stop at¬†red lights or stop signs and occasionally just decelerating into a tight turn.¬† It would always start right back up no prob but the same would repeat at the next stop.¬† Idle is where it's supposed to be, new fuel pump, cleaned and balanced injectors. plus I could find no loose vacuum lines or loose connectors.¬† To me the simplest and easiest troubleshooting was to unplug the Power Commander III and see what's up.¬† I did exactly that and took it for test ride #1 this afternoon and could not get the bike to repeat the problem. Hmmm.¬† I will repeat test ride tomorrow to be sure but so far it is looking like the PCIII may have been the culprit.¬† So my question is does that mean the PCIII was defective or could it have just been a bad map?¬† I have¬† zero experience with the PCIII's but have found an online manual @ DynoJet's website.¬† Also another question is does the bike even need this PC?¬† It is my understanding that the stock ECM is pretty capable of adjusting to changes such as my Two Brother's Pipes.¬† Does the PCIII actually improve HP, Torque, or MPG?¬† Or does it just give you controllability?¬† Thanks for any advice or sharing experiences with this.

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Did you remove the throttle bodies recently for some work? And did it do this before fitting the PC3?

Sent from my ONEPLUS A5000 using Tapatalk

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Know nothing about a PCIII but I have read where there have been running issues caused by bad Grounds for the PC. So have a good look at the wiring for it and make sure both power and ground wires have good solid connections. At least you've identified the culprit to your engine dying issues.

Cheers.:beer:

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Bike ran perfectly fine when it left showroom floor. There is no reason it shouldn't now if maintained in good condition.

 

It's air-flow mass that determines power and fuel & ignition needs to match for optimum output. With your mods, there is absolutely zero reason to have PCIII on your bike. Only needed if you've got extreme mods that factory ECU cannot adjust for. Such as big-bore high-comp pistons on stroker crank, larger valves with fully-radiused seats, D-ported intake-tracts, turbo or supercharger.

 

If you've got driveability problem, it's most likely maintenance issue. Worn plugs, cracked plug wires, dirty injectors, clogged fuel-filter or sock screen. This causes issue with spark and fuel. Using PC to try and compensate is not solution. Proper troubleshooting with testing and measurements to find faulty or misadjusted components is correct procedure. Followed by replacing worn-out faulty part and re-adjustments. Mis-adjusted TPS sensor and idle-switch is very common culprit.

 

In this case, very common for PC to cause more problems than it helps. Restore bike back to factory-fresh clean condition and it'll run perfect like when it left showroom floor. You're halfway there with disconnecting PCIII, now remove it completely and you've solved problem for good.

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OK after second test ride the issue has completely disappeared so obviously it WAS the PCIII. So since I am removing the PCIII I'm guessing I need to remove the O2 eliminators as well?

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no. you can leave those alone for now. Make only one change at a time.

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Had a similar problem with my 06 and a PC3. Turned out it was that where I had the PC3 located, which was in the space just behind the rear brake fluid reservoir shown in red. My sergeant seat had a tab on the underside that pressed on the PC3 when I sat squarely on it, like when stopped at a light, and it would start to misfire from then on. Went through all types of troubleshooting until I noticed the indentation on the PC3. I shifted the position of the PC3 to avoid the tab and has been working perfectly ever since.

 

 

PC3 space.JPG

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I had a similar problem with my VFR.  But I have a Bazzaz Zfi installed.

 

Whilst the Bazzaz was installed properly, according to the instructions, I really hate the use of scotchlocks.  They might work for a while, but in the end - in my experience, they just result in bad connections.  I traced it to the fact that the scotchlock that was connected to the switched power lead was dodgy.  I removed it and soldered the wire instead.  Then went around and removed the other scotchlocks that were used with the Bazzaz Zfi and haven't had any problems since then.

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