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cold start update

18K views 114 replies 22 participants last post by  TheRig 
#1 · (Edited)
The cutout or stalling problem when warm, cold or otherwise was NEVER caused by the Dynojet Power Commander 111. This was purely a faulty power supply within the right side switch assembly on the 919. Specifically the starter defeat feature when the kill switch is off, the contacts related to that, and their poor conductivity. Having ridden a full season and now well into the cold I can positively confirm that I have solved this issue.
 

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#3 ·
I don't buy it. The PCIII is involved. Mine was hard to start. Removed the PCIII--instantly & permanently fixed to this day. No changes to anything else. Starting test were immediately before removal & immediately after. The PCIII may not be acting alone, but it is involved.
 
#4 · (Edited)
Its an update, there are previous posts regarding this topic that have already covered these questions and other opinions several times.
If you have a PC111 installed and prefer to keep it, but are having starting issues you want fixed.........do a cold start search, happy reading.
 
#7 · (Edited)
Brilliant, especially for a moderator.
This is a simple and easy to prove power supply malfunction,
as stated by Dynojet from the beginning.
Get a used right side switch assembly for a cbr 600 or similar,
they are cheap and plentiful. Carefully break the connector to free the pins.
Open the headlight and disconnect the right side switch, plug the cbr pins in and you have just solved the issue.
 
#8 ·
as stated by Dynojet from the beginning....
yeah because they don't want to admit that their product is the actual problem/issue.

and you have just solved the issue.
No you haven't, because the only changing variable when the problem pops up is the pc3 itself.

If your "solution" is a permanent fix, then my "solution" of just holding down the start button a few seconds longer is an even better fix because you don't have to do anything. Not to mention its free!

Again, don't buy it. Been tested and proven repeatedly, the culprit is the pc3 itself.
 
#10 ·
The cutout or stalling problem when warm, cold or otherwise was NEVER caused by the Dynojet Power Commander 111.
I don't buy it. The PCIII is involved. Mine was hard to start.
Found the source of contention here. What everyone seems to have missed is apples and avocados are being compared, causing the misunderstanding. If it's hard or impossible to start it is probably the PCIII. Cutting out when riding (Meaning it has already started: an entirely different animal!) is the kill switch. Installing the Yamaha kill / start switch as seen in the OP photo cured the cutout problem, but would not necessarily cure a cold starting problem, which has absolutely nothing to do with the kill switch. How do I know? Look at the wiring diagram -- the starter circuit is powered by battery voltage supplied from the output side of the kill switch which also picks up the engine stop relay. If when the starter button is pressed the engine cranks over the kill switch is functioning normally and is not the cause of any problem.

If, however, the engine dies while riding the kill switch is a likely culprit (amongst a variety of other possible malfunctioning components), indicating poor contact in the switch that when affected by vibration or other external forces disconnects power to the engine stop relay, which does its job of stopping the engine when deenergized.

Just trying to get everyone to realize they are on different pages!

Rob
 
#11 · (Edited)
My PC111 is over 10 years old and mounted in a less than ideal location directly underneath the seat cowl. Throughout, its been neglected, exposed to constant heat from the silencer, annual cold winter storage, water spray when caught in the rain plus some significant pounding from a stiff rear spring setting. Also, considering the many hundreds of power fluctuations its received from repeated starting attempts, the thing's an effing champ, and I came very close to stomping on it.
On the other hand, Honda has supplied a switch that worked fine when new but began giving problems like power to the headlight for example. I cannot define exactly what the switch is doing wrong, its a make before break thing, but I guarantee changing it for a better one will make your 919 start first time, every time.
Your lack of comprehension is astounding, but you probably didn't get that.
 
#17 · (Edited)
Your lack of comprehension is astounding, but you probably didn't get that.
Granted. I did not do any research before responding. Now I have. Here's my take on it, and while testing it is impossible for me (no PCIII on my 919) it does make sense.

First, a basic assumption: installing a starter / kill switch assembly from a CBR cured the problem. Cool. The question is how did it cure it? First, it's probably a new or newer switch than the one it replaced and the contacts are relatively pristine, guaranteeing a cleaner voltage from the kill switch to the load it supplies. Always a good thing, but maybe not the whole story. Part two is the electrical difference between the two switches: stock, the power to the starter button comes from the output side of the kill switch which will disable the starter when the kill switch is off. The CBR switch does not have this function. Otherwise, they are electrically the same. On the 919 all the kill switch powers is the engine stop relay and the starter relay.

Next, some basics about relays. All conventional relays have two operational voltage ratings. One is pull up voltage, usually listed as the coil voltage. It creates a powerful enough magnetic field to attract the steel armature and make contact. The second rating, rarely specified outside the data sheet, called hold voltage. It is the minimum power required to maintain contact, usually about 60% of the pull up power. This will become important later. Another characteristic is when a relay is deactivated it generates a negative voltage spike, or "back emf" in the same way an ignition coil does which can go as high as -250 volts for a few milliseconds. Generally, the higher the current rating of the contacts the stronger the back emf will be.

Putting it all together, when the starter button is pressed the relay applies battery voltage to the starter motor. The load drops the battery voltage to about 10 volts if it's in good shape and it's warm out. The colder it is the harder the battery has to work to spin the motor, and at the same time the weaker the battery is. Under these conditions the voltage may come close to the hold up voltage of the engine stop relay, but still not low enough to drop it out. That is until the starter button is released, the relay deenergizes, and a negative voltage spike is generated which will be sufficient to arc across the just disconnected starter switch contacts and apply itself to the output side of the kill switch. Under normal circumstances it would be absorbed by the voltage line from the fuse box, but with contaminated contacts in a ten year old switch the bulk of it may apply to the voltage holding the stop relay closed, temporarily deenergizing it. The ECU is "hardened" against this with high value capacitors that keep it alive until the relay reengages. The PC, however, may lose its initialization and cut power to the injectors, killing the motor.

If this is the case, and keep in mind this is all speculation, how to cure the problem economically? Simple. All that needs to be done is eliminate the back EMF from the starter relay by adding a shunting diode to the switched positive line at the relay to ground with the cathode (banded end) connected to the positive line of the coil. It will ignore the starter signal but bypass the negative spike to ground. No spike, no stop relay dropout.

As I said before I can't test this, so if someone with a PC who has the cold start problem kluge this up for a quick test? At most it would cost a dollar or two for a 1N4007 diode and take maybe ten minutes to hook it up. At worst it will have no effect.

Rob
 
#19 ·
Rob, if you would be kind enough to provide a simple diagram I'll be the test subject. Mine has the cold start issue in a big way since it got colder this year, I had to start it at least five times last Friday before I rode. If I can cure it with a diode I'm game.
 
#20 · (Edited)
The attached thumbnails are of the starter relay gang plug and an edited schematic concentrating on the starter circuits and how they relate to the engine stop and starter relays. Included is the 1N4007 diode and its orientation. The lead at the banded end attaches to the Yellow / Red starter wire, and the other end to a good chassis ground.

For a description of the method of making a connection to a female terminal including how to remove it from the connector body: http://www.wristtwisters.com/forums/f94/599-headlight-8592-3.html

Post #86 on the third page. Too lazy to duplicate that here.

For experimental purposes I usually just jam a wire or test probe I want connected to a particular circuit into the well the pin is in, usually resulting in a sufficient if very temporary connection, and jump the anode lead to the nearest bolt head, in this case the 6mm bolt holding the coolant header tank on the other side of the backbone. In this way if it works (crossed fingers) you already have the setup and just need to make it permanent. If it doesn't ... well, that's what experimentation is all about. At least it will only take about a minute to remove it, shake your head, and start at square one again. There must be a solution somewhere!

Incidentally, the 30 amp main fuse is in the picture, and the exposed 5mm allen bolt is the battery positive connection, where my battery tender positive lead is connected.

Here's hoping.

Rob

Oh, and the turbo Encabulator is child's play compared to this! Unless, of course, the pitch gyro magamp saturates, precessing into the yaw domain and the inevitable happens: Descartes contribution to 17th century rationalism was neatly negated resulting in a massive temporal chain reaction, the foundation on which our civilization is built crumbles, and chaos rules the next two centuries. At the very least. I hate when that happens!
 

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#23 ·
Well this is an interesting development! With Rob's explanation and proposed experiment, drivit may be onto something.

But one nagging concern I have is how does a pc3 that didn't have the issue before, all of a sudden develop the problem and persist despite new batteries, contacts cleaned, and even swapping over to a different 919 that never had a pc3 installed, still carry the problem?

I don't know enough about voltage kick back to try and speculate on the different variables. I could however, see that depressing the starter button longer could prevent the pc3 from cutting power, based on Rob's theory. I'm curious to see what rmb's findings are, that is, if I don't get to it sooner.

Drivit, it's one thing to say you have an idea, but it's another when you don't provide an explanation or "proof" of a fix while proclaiming you have the solution and berate people for their doubts. So excuse the rest of us while we try to verify this via Rob's experiment.
 
#24 ·
Unless, over time, that voltage irregularity has caused circuitry issues (overheating ?) on the PCIII mainboard itself? Just a guess...

Might explain how the issue appears on the PCIII over time, then goes away when removed from the bike.
 
#26 ·
i just spelled out all the abuse mine has endured and it still works perfectly so....no......and its not my idea, its my solution. You got all the explaining you need to fix it and a guarantee.
Do you make your repairman explain every detail before you believe he fixed it. Because i'm from Canada it may or may not be an acceptable repair? Ever hear of intermittent automotive electrical problems? Nobody's forcing you to attempt the repair, if you threw your PC111 away and aren't pleased i wouldn't be either. I figured it out myself and detailed the procedure-big deal-it would have been a lot sooner if i wasn't misled by all the BS. Then a year later i graciously provide a final confirmation, prompt an excellent informative explanation as to why the switch is nada including a more economical, easier fix, and the BS keeps coming. No doubt there are several owners out there who also figured this power supply issue out on their own without ever having seen this website, wish i met one.
 
#27 ·
Yeah yeah, and Rob made more contributions in ONE post on the topic than all of the posts or threads you've created. Really insightful, thank you! Not to mention he was much nicer about it (Thanks Rob, as usual!)

If Rob's theory proves correct, then technically, changing the switch is not the more economical, easier fix. A $2 diode and 10 minutes of your time would do the trick (if tested and confirmed).

Meanwhile, I think I'll just stick with the proven (and multiple members confirmed) method of keeping the starter button depressed for a bit longer than average. The best part is, the cost is FREE.
 
#28 · (Edited)
Like I said at the beginning...the PCIII is involved, although probably not acting alone. The stock bike, by itself, has no issues regardless of the age or condition of the stop switch. Only the addition of a PCIII brings about the problem. This has been proven repeatedly by removing the PCIII & it instantly & permanently curing the issue on a previously affected bike. If the PCIII was truly innocent, the starting problem would remain despite its removal & the bike would still be hard to start due to the bad switch--but that does not happen.

If Rob's theory is true & I am reading it right, the different type of switch has no bearing on anything--just that it is a "new" switch with clean contacts. Clearly Dynojet is not as smart as Honda since Honda safeguarded the stock bike against this by integrating a diode or capacitors into the ECU as Rob alluded to. Dynojet could have done the same within the PCIII black box to avoid this issue but didn't.

Rob, my question is those with the issue--of which I was one---to get our bikes to start we had to partially open the throttle while thumbing the starter button & it would start fine while the starter button is released & all. How does the opening of the throttle enable the bike to start verses the idle position other than it is looking at a different place on the fuel map for info? Would not the PCIII still de-energize with release of the starter button if it is a power supply problem? I'm not challenging just wondering.:nerd:
 
#29 ·
Rob, my question is those with the issue--of which I was one---to get our bikes to start we had to partially open the throttle while thumbing the starter button & it would start fine while the starter button is released & all. How does the opening of the throttle enable the bike to start verses the idle position other than it is looking at a different place on the fuel map for info? Would not the PCIII still de-energize with release of the starter button if it is a power supply problem? I'm not challenging just wondering.:nerd:
I always just held the starter button down, which based on Rob's explanation likely allowed the voltage to return to a high enough level to not allow the relay to drop.

To answer your question, opening the throttle could prevent this in two ways, first of all, higher RPM=more charging, it could be that the higher RPM raises the battery voltage slightly faster to a point where the relay cannot drop.
or, more likely I think, the higher RPM allows the bike to stumble through the momentary loss of fuel/spark/whatever is cut when the PCIII loses power and doesn't have time to die before the power commander returns to duty.
 
#33 ·
I'm from Nova Scotia and ride regularly in the off season and store my beloved 919 outside(late April to December) - have a PC3 installed and have never once experienced the cold start issue. Not scientific by any stretch but just my humble 2 cents from eastern Canada.
 
#35 ·
No sadly, I sold my pc3 in preparation to sell the 919. One test he mentioned was to see if one could pull the headlight fuse and test the energy spike theory. If I recall correctly though from a track day, I don't think the 919 ecu will allow the engine to run with one of the essential fuses missing - the headlight fuse or the running lights fuse. Cant remember which one. Can you try the fuse test Rob mentioned?
 
#36 ·
Pulling the headlight fuse made zero difference. I've ordered a new lithium battery, supposed to have around 400 cold crank amps. I'll see if that helps. I've also got some diodes ordered. When I get them I will try that method Rob suggested. Battery and diodes should arrive next week. I post my findings. Thanks mate.
 
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