Exhaust leak

[exwinger]

Ok , have had the spyder in the shop numerous times for codes showing the bike running lean , one side or both. Had o2 sensors replaced , intake flanges replaced , hoses replaced , puter reset etc. , etc. and code still popped up running lean after a few miles. This last time he said the problem was caused by two small exhaust leaks . Have 100 miles on it now ( a record ) and no codes . My question , why would an exhaust leak cause a running lean code ? I think the problem is still there waiting to rear it's ugly head again when I'm out in the boonies but maybe I'm wrong . Originally it would go into limp mode but then after some parts replacement just the check engine light would come on and the running lean codes. Just maybe the exhaust leak was the main problem ?

[SpyderAnn01]

So have you ever replaced the exhaust gaskets? It is a pretty cheap fix and with your Spyder being older they are probably in need of replacement.

[garb55]

Lean condition usually is not caused by exhaust
It could be the 2 short vacuum hoses going to the throttle bodies
They may look good but if you bend them you will see small cracks
Most people replace them with silicone hoses
That said
I wish I had a vacuum hose I would cut it so I could look more lean

[Chupaca]

You may never have been actually running lean. The computer thinks you are from the information from the sensors. If the senors (O2) are reading the gases from the exhaust and they are leaking it may be sending the wrong message...

[Snowbelt Spyder]

I know it sounds counter-intuitive, but yes, air can be drawn into the exhaust due to a leak. Both, from when a slight vacuum is formed right after the exhaust valve closes due to pulsations, and by a venturi effect at higher flows-depending on the physical nature of the leak. Of course, for the O2 sensor to respond to the extra air, the leak would pretty much have to be upstream of it.

Remember, the EFI is operating in closed loop mode. As Gene stated, if the O2 sensor is sensing a false lean condition, the fuel injection system was trying to correct it by increasing fuel trim, which in turn made you actually run a little rich. No harm done if that was the case.

[SteveLaoyster]

I know it sounds counter-intuitive, but yes, air can be drawn into the exhaust due to a leak. Both, from when a slight vacuum is formed right after the exhaust valve closes due to pulsations, and by a venturi effect at higher flows-depending on the physical nature of the leak. Of course, for the O2 sensor to respond to the extra air, the leak would pretty much have to be upstream of it.

Remember, the EFI is operating in closed loop mode. As Gene stated, if the O2 sensor is sensing a false lean condition, the fuel injection system was trying to correct it by increasing fuel trim, which in turn made you actually run a little rich. No harm done if that was the case.

[exwinger]

That's what my idea is also , that the exhaust leak was the original problem and I had a lot of parts replaced that was needless. Fortunately all the parts and labor have been under warranty. The spyder has been running great the whole time with just check engine light on . Guess we'll have to wait and see if the codes come back. Gets a little unnervy when you see check engine and leery to ride it when you're 500 miles from home and in the mountains. Thanks all for ideas and thoughts. Dealer said as long as it's just the check engine light and nothing else to just ride it until I can have it serviced.......................but then it's not his money he's spending either .

[exwinger]

Well after another 130 miles after getting it out of the shop last week ( been i 5 times already this year ) the check engine light is back along with the lean bank codes. I didn't think the exhaust leak was the problem but one never knows with these high tech engines. I did contact BRP when I took it in the last time to the shop and was told that if it happens again after all the problems I've had with it to contact BRP before contacting the dealer which I intend to do first thing in the morning. The dealer has refused to contact BRP and start a case file on this problem even though the last time I told them twice that I was instructed by BRP to tell them I wanted one opened .BRP has said they will start the case file now and the dealer will be assigned a tech for this problem and will give the dealer specific instructions on troubleshooting . I can't figure out why a dealership would continue to keep guess on what they think the problem might be instead of going to the experts .What really gripes me is we have a long trip scheduled on the 8th with other riders and that I'll maybe have to cancel .Even if I get the bike back I'll be very leery about taking it and then on the 20th I have another ride to the twistys in N.Carolina with another friend and this trip last year was when the problems started and I ended up losing 1 1/2 months of riding . BRP came thru for me on a bad electrical problem that was plaguing me and hope they can solve this one for me .It was a different dealer with the electrical problem and they didn't hesitate to contact BRP for help. Unfortunately when the latest problems started I couldn't use the other dealer.

[Mickay]

100% Sure it's exhaust leak. Look between manifold and catalyzer. If you have a leak from cylinder 1 it's will cause P1074 Too Lean on cylinder 2,and vice-versa. For whom you know what i'm talking about. Compare the distance between the 02 sensor and the joint/gasket/leak. They are not on the same place on the pipe.

I try to explain but you could see english it's not my native language.

Leak will let introduce fresh air in the system that affect the 02.

I had the p1074 for 2 years try to troubleshoot but never see a clear sign of leak on the pipe. I slack the c-clip on both 2 side to make sure to create a leak to release some pression cause by the catalyser. It's take 50km and the code disappear. Now i'm on my 500 km. No more P0174 i'm at 70 000km with a RT 2010.

So change it.

Hope , i help someone.