CO Adjustments

[Denver_FJR]

I don't think it's going to be possible to change the decel/accel jump. The FI system on our bikes just doesn't make a very smooth transition on that. Since the PCIII makes modifications to existing injector pulses, I don't know how we could use one to make any changes there. You just can't modify injector pulses when there aren't any being produced.

Hot wire the clutch switch so the FI thinks the clutch is disengaged and doesn't cut injectors?

Full disclosure... I say this in jest. It would probably have a bad effect on safety cutout systems. Caveat emptor and all that.

 

[Fred W]

This doesn't have anything to do with the clutch. The ECU cuts fuel injection pulses when you are decelerating with a zero throttle opening and the rpms are somewhere above idle speed (not sure how much above idle it has to be). Clutch state doesn't enter into that at all.

 

[joebiodiesel]

I don't think it's going to be possible to change the decel/accel jump. The FI system on our bikes just doesn't make a very smooth transition on that. Since the PCIII makes modifications to existing injector pulses, I don't know how we could use one to make any changes there. You just can't modify injector pulses when there aren't any being produced.

Hot wire the clutch switch so the FI thinks the clutch is disengaged and doesn't cut injectors?

Full disclosure... I say this in jest. It would probably have a bad effect on safety cutout systems. Caveat emptor and all that.

I know you're just kidding, but so you know, the PCM looks for high RPMs, Closed Throttle, and High Vacuum(Low MAP Sensor) readings to know that the bike is engine braking. Then it cuts the injectors off until any of those readings indicate it needs fuel again.

It took GM almost 10 years to figure out how to take the off/on transition in a smooth fashion, and they were using a much faster processor than what they started out with. I can't see it being fixed by the aftermarket, or a couple of clowns with PCIIs.

In fact, I was beginning to doubt I can even use the thing at all. After my ride yesterday I was really happy with my latest settings. I took my wife for a ride and it ran as bad as it ever did. I didn't figure out what was going on until I only went about 160 miles on my tank of fuel. I definitely got a load of bad gas because the next fillup returned the bike to normal. I was pretty darn frustrated for a couple of hours though, and my wife was beginning to think I was nuts.

So, after doing an awful lot of monkeying around with my PCIII I am convinved of a couple of things:

I'm not going to be able to make the bike better than my present settings.

The 5 gas readings when it misses on accel between 1-2K RPMs are normal, so whatever is going on, it's not fuel mixture.

I may spend some more time trying to diagose what's causing it, but right now I can just run the clutch like a rookie and keep the revs over 2K when launching the bike.

Joe

 

[joebiodiesel]

The 1-2K RPM miss has been driving me bonkers. It's enough to piss off the Pope! Last night I spent some more time diagnosing it, and like usual I learned a few things, and ended up with more questions than answers.

Here is why it runs rough at 1-2K RPMs. The computer is adding extra injection pulses like it is accelerating.

The computer normally adds extra injection pulses when extreme enrichment is needed, like when the throttle is opening. Only between these RPMs do I get extra injection pulses like this. As soon as the engine hits 2000 RPMs, it disappears. Anytime I've ever seen anything like this on a car the first thing I suspected was a bad TPS. Rapid fluctuations in TPS voltage, even small ones, can result in a whole lot of extra fuel getting added. It's not that it can't be anything else, it's just that the TPS is the number one suspect. It was adjusted within specs but I decided to fool with it, trying several different closed throttle voltages. Every time I moved it, the RPM where it missed changed. Furthermore, if I substituted the signal with my signal generator, the problem disappeared.

Here is what the TPS looked like on the scope.

It's pretty easy to see that it drops to 0V for a tiny slice of time. Less than 300 microseconds, in fact. I figured there was NO WAY the primitive processor in the FJR could see this spike, but I couldn't find any other reasons for the false enrichment. I scoped MAP, Crank/Cam, and came up empty handed. Before spending $200+ on a TPS I ran the bike with the TPS unplugged, and the PCII accelerator pump turned on, and way up. Aside from the Engine Light being on it ran pretty darn good, aside from the surge that the PCIII fixed. I rode 40 miles of mixed riding looking for the problem to come back, but it didn't. I was convinved I needed a TPS. I put one on, and the bike ran no better than the original one. Anyone wanna buy a nice, low mileage TPS?

So here is where we are: The PCM is adding tons of enrichment only between 1-2K RPMs. I can't find any input other than TPS that is acting incorrectly. A new TPS doesn't fix it, but substituting a known good signal does. It just doesn't make any sense.

At this point I'm really wishing I had another bike to throw the scope on. In the mean time I may check to see if I can get the bike to go into closed loop without a TPS input. I'll unplug the wire from the PCM so the PCIII can still operate normally and see what happens. If anyone has any suggestions I'd glady consider them.

Joe

 

[Fred W]

Yeah, you should definitely try to get your scope onto another 2nd gen bike and see if yours is unique.

In this waveform:

If the ECU was intentionally adding fuel I would expect it to look like trace 1. Traces 2 and 3 the "normal" timing pulses are all raggedy looking, and the added pulses are clean. That doesn't seem right at all.

 

[joebiodiesel]

If the ECU was intentionally adding fuel I would expect it to look like trace 1. Traces 2 and 3 the "normal" timing pulses are all raggedy looking, and the added pulses are clean. That doesn't seem right at all.

The raggedy pulses are extra ones that are used when there is a call for lots of extra fueling. The top trace does it also, just not in this particular spot.

Today I did some more fooling with the bike. I disconnected the TPS, turned on the Accelerator Pump feature of the PCIII and cranked it way up. The bike hits closed loop just fine, in fact it seems to enter it quicker and more often. It will even cycle the O2 during steady 1-2K RPM operation, which it never did before. The bike runs like it ought to. It still continues to work normally after the Check engine light illuminates, which took almost 40 miles today.

Anyone else want to try this to clear up their throttle roughness at 1-2k RPMs? If you already have a PCIII, just unplug the TPS, Install the Accelerator Pump feature, and use the following settings to get started.

RPMs 3

Sensativity 80%

Fueling 80%

Please let me know what you think.

If anyone is close to Syracuse, NY, or near Orlando, Fl this week and wants to get together, please let me know. I'd love to put my scope on another 2nd Gen bike.

 

[joebiodiesel]

I rode my bike about 400 miles with the TPS disconnected and the PCIII adding all the fuel I needed for acceleration enrichment. My bike ran like a Swiss watch, like it ought to. Everything was great until I passed a gaggle of pirates on their way back from Americade. The acceleration over 80 MPH was a little soft, and the bike topped out a little over 100MPH. It was brutally lean at high RPMs. :-( Back to the drawing board.

By the way, the spit and sputter that FJRs do at idle is gone with the TPS disconnected. As a last resort I could add the fuel I need at full throttle with the PCIII, but I'm still bent on fixing the false enrichment at 1-2K RPMs.

Joe

 

[joebiodiesel]

If anyone is close to Syracuse, NY, or near Orlando, Fl this week and wants to get together, please let me know. I'd love to put my scope on another 2nd Gen bike.

No takers? I don't want to change anything on your bike. I just want to scope the injector signals. We don't need to lift the tank or anything. I just need to back probe a couple of wires at the PCM.

 

[Crash Cash]

If anyone is close to Syracuse, NY, or near Orlando, Fl this week and wants to get together, please let me know. I'd love to put my scope on another 2nd Gen bike.

No takers? I don't want to change anything on your bike. I just want to scope the injector signals. We don't need to lift the tank or anything. I just need to back probe a couple of wires at the PCM.

Hey, I'm on the east side of Orlando south of UCF, with an '07. I might have to work Saturday 18th for a production software rollout, but I'll be free on Sunday 19th.

I assume PCM is a typo for ECM? I have the new ECM after recall with the altitude fix on it, and I also have a throttle spring unwind and the G2Ergo cam. I did the Barbarian jumper mod, but all my settings are back to stock.

 

[joebiodiesel]

Hey, I'm on the east side of Orlando south of UCF, with an '07. I might have to work Saturday 18th for a production software rollout, but I'll be free on Sunday 19th.

I assume PCM is a typo for ECM? I have the new ECM after recall with the altitude fix on it, and I also have a throttle spring unwind and the G2Ergo cam. I did the Barbarian jumper mod, but all my settings are back to stock.

I'll be back home in NY by Friday night. :-( Any chance I can come out your way one night after work? I get done right around 4pm every night this week. It won't take very long to do, so I won't be taking up your whole night. PCM=Powertrain Control Module. The auto industry switched to that when they gave most of the transmission shifting duties to the ECM, Engine Control Module. I use them interchangeably....sorry. I'm still a rookie on bike electronics.

Joe

 

[Crash Cash]

I'll be back home in NY by Friday night. :-( Any chance I can come out your way one night after work? I get done right around 4pm every night this week.

Sorry... it's release time, and I'm not getting off work 'til 8 or 9pm and then I have to grab dinner before I start gnawing on someone's leg. I'm on a "waiting for crap to compile and deploy to the stupid exadata" break right now, as a matter of fact.

 

[joebiodiesel]

Sorry... it's release time, and I'm not getting off work 'til 8 or 9pm and then I have to grab dinner before I start gnawing on someone's leg. I'm on a "waiting for crap to compile and deploy to the stupid exadata" break right now, as a matter of fact.

[sigh]

No problem. I do appreciate the offer though!

I'm doing classes from 8-4 until Thursday, then off to Tampa on Friday, then back home to Syracuse Friday PM. There is an thread from last summer with a bunch of guys complaining of the same 1-2K rpm miss. I'll try reviving that thread (if I can find it again) and see if I can't find a volunteer.

For any lurkers, next week I will be in Albany, Newburgh, Poughkeepsie, Westchester, NY area.

Joe