Dynotjet Pc Ii Problems

[ggathagan]

Years ago, I bought a DynoJet PCII off the Internet for my '01.

I had bought a Wolf underseat exhaust and wanted to improve the fueling curve.
When I installed it, however, I had problems with the engine cutting out.

Too often it would occur are the worst times, like midway through a curve.
I bought the O2 eliminators, but that didn't change anything.
Then I discovered that the PC was meant for the '98-'99 model with the 'choke'.
Dynojet was kind enough to reflash the unit for '00-'01 bikes, but that didn't improve anything and I finally took it off.

Fast forward to today.

I'm on my 2nd '01 and recently bought a Staintune highmount from a fellow VFRD member who included a PCII with a map for the Staintune (Thanks Maxswell!!). The map helped smooth out the acceleration and minimized the snatchiness when initially opening the throttle, so I was quite pleased with it.

I don't ride the bike daily as I used to, so it's rare that I'm in heavy traffic for any length of time.
This past week, however, circumstances forced me to take the bike to work.

As I was riding home in normal Honolulu traffic (20-25 MPH for about 20 miles), the bike started cutting out, just like the other bike did so many years ago.

This time, however, it was much more frequent.

I'd say about 2-3 times in the span of 2 minutes, but not at regular intervals. I couldn't discern any sort of pattern to the problem.

Due to traffic, the bike was hot, but not obscenely so.

The temp gauge would hit 220, the fan would kick in and it would drop down to 210.
I experienced the cut out in 1st, 2nd, and 3rd gears.
I experienced it under acceleration, under deceleration and under heavy acceleration.
This time around it was not on a curve; strictly straight line.

As I got closer to home and traffic thinned out, the pace picked up, the bike cooled down and the problem went away.

Although it would seem to be a heat-related issue, the fact that the PCII is mounted back by the ECU would lead me to believe that it's not a matter of the PCII itself overheating.

Another data point: The red FI indicator doesn't light up with the PCII installed, so I've not bothered with the O2 sensor eliminators.

Has anyone else had this problem?
Is it possible that there's a mapping issue? That doesn't seem like a logical cause, but I'm not well versed in how the PC modifies the ECU signal.

Dynojet lists the PCIII USB as an applicable model for the 5th gen.
Is it, or any other product, worth consideration to deal with this issue?

[Knight]

I was thinking that since ostensibly this device worked for the member who sold it to you, that the issue is your bike.

Since it happens under all throttle conditions it would not seem to be an extreme fuel (rich/lean) issue but otherwise hints that heat is causing something electronic to flake out. I would expect the PCii to handle all forms of motorcycle heat so maybe the bike connector's are corroded. Disconnect the PCii and inspect the connection carefully. Check the PCii power/ground wires and the bike's applicable ground. Grounds are prime suspects. Clean them thoroughly.

I have a PCV (1999 VFR). I was told by my mechanic that the cable was taught. Otherwise it works fine. I do city riding in 90°F weather with no issues. The one advantage of this over the PCiii is you can also buy more junk like a Wide Band 2 and make adjustments to the bike off an O2 sensor yourself. Otherwise if you got a deal on a PCiii that would do the same thing. Regarding the PCV Dynojet says, "it works but we don't support it". I did it anyway.

[ggathagan]

Thanks for your reply, Knight

When this occurs, the engine just cuts out and the tach drops to zero.
It doesn't have any of the characteristics of a fuel-related problem, but rather an electrical/electronic problem.

I've never had it happen while at a standstill, so I can't say for sure if the engine comes back up on it's own or if the bike is essentially jump-starting itself through its own inertia.

The bike has very low miles (just over 14K) and is in mint condition. All the rubber tubing is still supple, as is the wiring.

Point being that the bike is close to showroom condition; no rust, no oxidation on aluminum bits, no corrosion; nothing.

I inspected the ECU and PCII connectors prior to installing it and saw nothing wrong.

As to heat: If it was my old Wolf underseat exhaust, which came with a metal replacement for the stock under seat tray, I could see a possible heat issue with the ECU and PCII.
With the stock underseat and the Staintune, there's no way the back of the bike's tail is getting hot .

I've had the bike for just under a year and have never had this happen prior to hooking up the PCII.
The previous owner, a close friend, has never had any issues with the bike and he's had it since it had about 1300 miles on it

If I didn't have the identical symptoms with a different '01, and a different PCII, I might be inclined to think it was the bike, as well.
The whole deja-vu aspect of it tends to steer me away from the bike being the source of the problem.

[wera803]

I had a PCii on my 2001 for a while before I upgraded to the PCiii. The only real issue I had with it was when I got a map from someone else for a 1998 and used it. I think there was timing advancement in the map or something that my bike really did not like. Basically I had to pull the timing advance out and just run stock timing. That usually gave me an issue at higher RPM's.

This was probably 10 years ago though and I am going off memory, which isn't as good as it used to be.

More recently, I had a problem with my GSXR cutting off. Tach would drop to zero. I thought it started happening right after I put a PCiii on that bike, but it just happened more for some reason. After chasing it for months, found it was the side stand switch. The stand would resonate at certain RPM's and cause the issue.

[Knight]

Does the PCii connect to the ECU? Is the ECU flopping about?

Let's connect the two thoughts that something is in motion + the problem exists only when the PC is connected: People have had problems with ECUs in motion. If yes, secure the ECU. Problem go away?

[MaxSwell]

Sorry you're having a problem pal. That 1300 miles I put on the bike was during T-Mac; it hit mid 90's F and I saw engine temps of up to 230F. So, unless something is wearing out with the PCII, maybe it's electrical.

My first 2001, at ~ 80,000 mi, started cutting out and acting weirdly other ways (in order): 1) started to seem to loose power, 2) cutting out irregularly, 3) I'd activate my turn signals and the tach/speedo would drop to zero until I turned the signal off, then they leaped to the proper reading, 4) the speedo/tach would drop with the signal light on and immediately jump when the light didn't blink. Light blinks bright: no speedo/tach, blinks off: return to normal.

This happened gradually over ~ 100 mi. I turned around at this point and 100 mile later it quit completely. Dead as a door nail.

It turned out the r/r was shot and the stator was fried. Hope this is not your issue but I'd suggest you try "the drill".

Good luck.

[maxredline]

Dont forget to improve your ground block if you haven't already...its worth money in the bank!