The reason why I'm checking things

[justacrossthehill]

My bike was running great until I pinched a wire from the O2 sensor under the RH engine cover. It blew the fuel injection fuse which I replaced after repairing the wire. Problem is, now I have a bad stumble right off idle. The bike still runs great once the transition is made from idle. It has been ridden probably 400 miles since this happened and it has no stored codes nor has the check engine light been on except when turning the key on. I have an O2 sensor on the way but am now wondering if I have smoked something in the ECU. Bike is an 08 with 16K miles. I just removed all the vacuum lines around the MAP sensor and found no restriction and no leaks. Also, when checking the output voltage directly at the TPS, it increases gradually  all the way to wide open throttle and is in spec at idle. It also passed it's test in the diagnostic mode. 

Ideas please? 

 

[1911]

O2 voltage?

 

[justacrossthehill]

Next time I have it running I'll check that. Hadn't thought of that at all, thanks for the suggestion. 

When I shorted that wire to ground, I took out a 15 amp fuse and I'll be surprised if I didn't take something else out at the same time.

I'll keep plugging away at it and if I ever get it fixed, I'll update this thread.

 

[1911]

Next time I have it running I'll check that. Hadn't thought of that at all, thanks for the suggestion. 

When I shorted that wire to ground, I took out a 15 amp fuse and I'll be surprised if I didn't take something else out at the same time.

I'll keep plugging away at it and if I ever get it fixed, I'll update this thread.

I’ll be watching/curious. I’m thinking you must have pinched the wire for the O2 heater circuit? There’s a thread on here somewhere where I sought info while chasing down my own gen 2 hesitation issue. I spent a lot of time watching o2 tps and map voltage.

 

[justacrossthehill]

I’ll be watching/curious. I’m thinking you must have pinched the wire for the O2 heater circuit? There’s a thread on here somewhere where I sought info while chasing down my own gen 2 hesitation issue. I spent a lot of time watching o2 tps and map voltage.

Yea, the heater circuit is what I believe I took out. The blown fuse was for the fuel injection. When the bike didn't start, I noticed the fuel pump didn't come on so I went from there discovering my mistake.

Not much in the manual about the O2 sensor that I've found.That and throttle body setup info seems to be very scarce.

When I bought this bike it was idling at 800 RPMs but at the time I didn't know how to raise that. It ran great for the 300 mile trip home other than idling too slow. Once home, I replaced the air filter, checked the throttle body sync which was good so I didn't do anything there, and pinched that wire fixing the oil leak at the cover. As for the idle speed, all I can get is a hair over 1000 RPM's so I may have something going on with the throttle bodies instead of an electrical problem. Those old obsolete Mikuni's on my FZ1 are looking pretty good right now. 

I'd love to hear whatever you remember about your hesitation problem.

 

[justacrossthehill]

Back playing with the bike a while this morning, no matter how I connect an ohmmeter through the MAP sensor and apply pressure or vacuum, I see no change in resistance. How can that be if this sensor is working?

Guess I should put the bike back together and check the output voltage.

Started from square 1 and pulled the valve cover to be certain everything is in time and did a valve check while in there so I'll be skipping this at 26K

 

[RossKean]

Back playing with the bike a while this morning, no matter how I connect an ohmmeter through the MAP sensor and apply pressure or vacuum, I see no change in resistance. How can that be if this sensor is working?

No error codes?

Don't apply too much pressure or vacuum to MAP sensor.  They may not like it!!

Regarding idle adjustment...  The adjustability on a GenII may be a function of your throttle body synchronization.  Most people just adjust the screws to get them all the same and this is the most important.  If the reference cylinder is not where it should be, you may find you can't adjust idle enough.  Try a TBS after setting all of the screws between a half and three quarters turns from lightly seated.  This usually works...

Note: Don't make major adjustment changes if you have a mechanical/electronic issue is causing the problem.  It is unlikely that the ECU was damaged - they tend to work properly or not at all.

You might try running with the O2 sensor disconnected.  They run pretty well with no O2 sensor but not so well with one that is not reading correctly!!  (I pinched mine in the case upon reassembly and it messed things up!!)  https://www.fjrforum.com/topic/140471-shorted-oxygen-sensor/?tab=comments#comment-892900

I assume that you are not using a Power Commander or other device that affects the fuel mixture??

 

[justacrossthehill]

No sir, no codes, all stock and everything checks out in the diag. mode. 

One thing I noticed though and the reason I checked the cam timing, when checking my throttle body sync, the vacuum level I'm seeing is less than I saw on a couple of U Tube vidoes. Mine only gets to 16 on my Morgan Carbtune and in the videos I was seeing the 22-24 range.

 

[RossKean]

As I said.  Do the TBS from scratch with the reference cylinder open 1/2 to 3/4 turns.

 

[justacrossthehill]

Finally fixed my bike. In addition to what I mentioned that I did above, I also worked on a few ground spiders. Of the two at the left rear engine, one has the ground circuit going back to the ECU for the engine sensors. I really don't think I had a bad connection but if it wasn't that it must have been the additional frame ground I added there. I was looking at the print and saw all those grounds tied in together on the way to the ECU and got the idea that Yamaha may have intended for the ECU control the ground so I cut out the extra frame ground there and redid my crimp/solder job where that spider was. I wish I had just cut that ground and tried it before redoing the splice but didn't. Before I made that splice initially, I checked each wire and one had a solid ground on it so I figured another ground there could only be good but that may have been a mistake. Anyway after checking everything and finding nothing out of spec it's now running as it should or probably better than it was. At least my idle speed is correct now. I did everything possible to the throttle bodys and feel like they are spot on. Thanks for the suggestions and I followed every one to the letter.

I've made my living working on things since 1977 and can't remember anything kicking my a$$ like this has.  Part of it is my age I guess because my ole noggin doesn't function like it used to.

Now at least, maybe I can ride this thing some.