Question Temperature dependent idle issues??

[quixitoc]

My FZ6 has a strange issue when it gets cold outside. When ambient temps are above 60-70 degrees Fahrenheit (so nice warm riding weather), my bike runs perfectly, idle is steady, performance is great. However, when it gets colder out, weird stuff starts happening. During this cold weather, after about 15-20 minutes or so of riding, the idle becomes strangely high (up to 2000+ rpm). Then, after about 30 minutes to an hour, the idle drops drastically, sometimes below 1000 rpm, requiring me to give it throttle to keep it alive. I would think this would be a throttle body issue or something to do with tuning, however, as soon as I key off and key on the bike again, the bike's behavior becomes completely normal, until 20 minutes later where this odd behavior repeats. I'm thinking because of this it may be an electrical issue, but I have no idea what specifically is causing this.

 

[Gary in NJ]

There is a water temperature sensor in the throttle body assembly. The sensor may be fine, but corrosion in the tube may be causing inconsistent readings. We have seen this failure several times from forum members.

 

[quixitoc]

There is a water temperature sensor in the throttle body assembly. The sensor may be fine, but corrosion in the tube may be causing inconsistent readings. We have seen this failure several times from forum members.

Gotcha, is there a part number or diagram of it that I can look at? It's an 04.

 

[Gary in NJ]

You know...I've read about this but never took the time to look it up myself. I just read the entire FSM and I can't confirm that such a system exists. I have a spare engine in my garage and will inspect it to identify how the system works.

Are you getting any fault codes? If the coolant temperature or intake air sensors have failed you will typically get an unpredictable idle.

 

[Gary in NJ]

I found it…it does exist. It’s not called out anywhere in the FSM for the fuel injection system or the throttle bodies, but the hose routing for the cooling system shows “throttle body hose”. That's it - this part is NOT shown in the microfich as a part number (or description) nor is its operation or use described in the FSM.

If you look at the photos below, the unit on the left with the vertical hose outlets is the idle adjustment and throttle body sync. The two horizontal hoses on the right are part of the cooling system and help the throttle bodies maintain a constant temperature - once the bike is warmed up. This is a mechanical device without a sensor...so data does not go to the ECU. If this is clogged you will not throw a code and the temperature in the TB will be inconstant - which can result in idle problems.

 

[quixitoc]

I found it…it does exist. It’s not called out anywhere in the FSM for the fuel injection system or the throttle bodies, but the hose routing for the cooling system shows “throttle body hose”. That's it - this part is NOT shown in the microfich as a part number (or description) nor is its operation or use described in the FSM.

If you look at the photos below, the unit on the left with the vertical houses is the idle adjustment and throttle body sync. The two horizontal hoses on the right are part of the cooling system and help the throttle bodies maintain a constant temperature - once the bike is warmed up. This is a mechanical device without a sensor...so data does not go to the ECU. If this is clogged you will not throw a code and the temperature in the TB will be inconstant - which can result in idle problems.

View attachment 75570View attachment 75571View attachment 75572

OK, I'll be sure to clean that out next time I open the bike up, although I don't see why this condition would change as soon as I key the bike off and on.

 

[Gary in NJ]

You are sure that you don't have any fault codes?

 

[TownsendsFJR1300]

I think you can check the intake temp sensor with the two "clock buttons" on the display.

Check and see if the temp suddenly drops (perhaps causing it to go into cold start/high idle mode..) when it shouldn't

.

 

[Gary in NJ]

Good call Scott. You can see what the ECU sees in real time.

 

[quixitoc]

You are sure that you don't have any fault codes?

I think you can check the intake temp sensor with the two "clock buttons" on the display.

Check and see if the temp suddenly drops (perhaps causing it to go into cold start/high idle mode..) when it shouldn't

.

No codes, coolant temp seems normal and behaves as I would expect. Which “number” of the diag menu is the air temp?

 

[TownsendsFJR1300]

I think it's just under the menu, in the instrument cluster...
it's not a diag code.

We don't know what year bike you have, it may be slightly different between the S1 and S2.

I can send you a PDF owners manual (which is where it would be).
PM me with the model and an address and I can send it to you..

.

 

[quixitoc]

I think it's just under the menu, in the instrument cluster...
it's not a diag code.

We don't know what year bike you have, it may be slightly different between the S1 and S2.

I can send you a PDF owners manual (which is where it would be).
PM me with the model and an address and I can send it to you..

.

Found it in my service manual, will try once I finish painting the bike. Thanks!

 

[Makiabelhs]

behind this black cap is the auto choke, mine whose stuck.
i screw the little safety nut, then the revs goes hi when the engine was cold, i turn it back to the original position and now works fine, that s why i suppose it whose stuck.