ECU / Air Pressure Problems with my '04 Feej?

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Flylooper

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Here's something which may or may not be one of those oddities.

A couple of years ago on a trip, I noticed that sometimes (not all the time!) my completely stock '04 sputters, coughs, and runs quite rough when started from cold (like after having sat over night.) The check engine light lights up, which is scary enough in itself. I interpreted this to a problem with the cold bike not getting proper air-fuel and/or timing settings.

But I soon discovered that if left alone to warm up, once the temp come up to something approaching normal operating temp the thing smooths out as though nothing happened. I also came to notice that the problem only occurs when the bike is at some kind of elevation e.g., in the mountains or hills above about 2000 ft. When at home, which is at roughly sea level, there is absolutely no problem with startup from cold.

Except this morning! I fired up the bike and it sputtered for about 10 seconds. BUT today a low pressure front is moving through the Willamette Valley, where I live.

The questions:

1. Does barometric air pressure play a role in how the ECU functions?

2. Is the ECU the culprit?? :blink:

TIA for your thoughts.

Bob

 
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A couple of years ago on a trip, I noticed that sometimes (not all the time!) my completely stock '04 sputters, coughs, and runs quite rough when started from cold (like after having sat over night.) The check engine light lights up, which is scary enough in itself. I interpreted this to a problem with the cold bike not getting proper air-fuel and/or timing settings.
I'd wonder first if you might have the throttle position sensor issue that supposedly affects all 2004 bikes.

 
A couple of years ago on a trip, I noticed that sometimes (not all the time!) my completely stock '04 sputters, coughs, and runs quite rough when started from cold (like after having sat over night.) The check engine light lights up, which is scary enough in itself. I interpreted this to a problem with the cold bike not getting proper air-fuel and/or timing settings.
I'd wonder first if you might have the throttle position sensor issue that supposedly affects all 2004 bikes.
I had that done at the dealer when the SB came out. I don't think that's the problem. But then...... :(

 
Here's something which may or may not be one of those oddities.
A couple of years ago on a trip, I noticed that sometimes (not all the time!) my completely stock '04 sputters, coughs, and runs quite rough when started from cold (like after having sat over night.) The check engine light lights up, which is scary enough in itself. I interpreted this to a problem with the cold bike not getting proper air-fuel and/or timing settings.

But I soon discovered that if left alone to warm up, once the temp come up to something approaching normal operating temp the thing smooths out as though nothing happened. I also came to notice that the problem only occurs when the bike is at some kind of elevation e.g., in the mountains or hills above about 2000 ft. When at home, which is at roughly sea level, there is absolutely no problem with startup from cold.

Except this morning! I fired up the bike and it sputtered for about 10 seconds. BUT today a low pressure front is moving through the Willamette Valley, where I live.

The questions:

1. Does barometric air pressure play a role in how the ECU functions?

2. Is the ECU the culprit?? :blink:

TIA for your thoughts.

Bob
Go through the diagnostics and see if you find error codes for 13, 14 or 23. All three involve air pressure. A service manual is a MUST.

 
When I had my 04 in for the tps recall the tech asked me if I had any problems with the bike at higher altitudes. After I told him no he

informed me there was a recall dealing with rough running at altitude but was only to be fixed if the owner complained.

I don't have any other information on the recall.

David

 
Here's something which may or may not be one of those oddities.
A couple of years ago on a trip, I noticed that sometimes (not all the time!) my completely stock '04 sputters, coughs, and runs quite rough when started from cold (like after having sat over night.) The check engine light lights up, which is scary enough in itself. I interpreted this to a problem with the cold bike not getting proper air-fuel and/or timing settings.

But I soon discovered that if left alone to warm up, once the temp come up to something approaching normal operating temp the thing smooths out as though nothing happened. I also came to notice that the problem only occurs when the bike is at some kind of elevation e.g., in the mountains or hills above about 2000 ft. When at home, which is at roughly sea level, there is absolutely no problem with startup from cold.

Except this morning! I fired up the bike and it sputtered for about 10 seconds. BUT today a low pressure front is moving through the Willamette Valley, where I live.

The questions:

1. Does barometric air pressure play a role in how the ECU functions?

2. Is the ECU the culprit?? :blink:

TIA for your thoughts.

Bob
OK, thanks for posting this! I have an 07 that has a very similar problem. I live at 530 feet above sea level. 3 weeks ago, I started up my bike cold and then it stumbled and died. The engine light came on and I restarted it. After giving it some throttle it was able to keep running and as it heated up it got better. After I drive it a few miles I can restart it like nothing ever happened and the engine light stays off.

2 weeks ago I went on a 2500mi trip and not once did the bike repeat the strange behavior. All of the trip was between 2600ft and 8000ft above sea level. The next morning after returning from the trip it did it again.

The diag code shows #14 air hose malfunction but the tube is clear and un-kinked. The bike has a new air pressure sensor I added to see if it made a difference and it cleared it for a day and had quite a bit more power but then started its old tricks again. The ECU was upgraded a couple of years ago with a non altitude sickness ECU.

I don't know what is the trouble :huh:

 
The ECU recall was not specifically for rough running at altitude, but for rough running after the altitude changes.

Apparently the ECU only sampled barometric pressure at start and assumed it didn't change, and as you climbed your favorite mountain road the bike started to suck. Shutting off and restarting fixed it, as the ECU would re-sample then.

New ECU pays more attention to what's going on outside, evidently.

IIRC, that recall was for early Gen-II bikes, would not apply to an '04.

 
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