Was at Sturgis, sitting in idle traffic on main one day and it was over 90 deg.

I have a Thundermax ECM.

Engine starting getting really hot. Check engine light began flashing for about 10 min. Then it went solid.

Then the RPMs at idle shot up to around 2000 I think, maybe a bit more...very noticeable.

I then shut it down. After a while I fired it up and got out of there and it's been fine ever since.

Using Harley SE Synthetic oil.

Any suggestions about what happened?? I know it was overheating, but can anyone explain the process? It it a Harley or T-max thing to go faster idle??

 

From what I've read,the ECU will inject more fuel to help cool the engine.

 

huh... usually when a HD over heats it shuts down the front cylinder and runs off the rear, the bike runs real real choppy sounds like what happened to your scoot bud

 

Regarding what JRK said, Harley-Davidson refers to that as "Parade Mode."

 

The Touring bikes shut down the back cyl for rider comfort at idle and when in over heat mode it also injects more fuel into the front while the Dynas inject more fuel into both cyl. in over heat mode at idle.

 

Yea, I've read all that searching through the forums. But mine didn't cut one cylinder at all...it sped up the RPMs instead.

I'm wondering if the T-Max actually changes what occurs when the bike overheats.

 

It's the rear cyl that shuts down, the front gets more air so they wouldn't shut down that one. If you blip your throttle the parade mode won't come on. When the light flashes it's time to find a place to park or some open road, when it stays on shut it down.

 

There are two types of parade mode implemented by HD, the richen the mixture and then either shut the rear cylinder down mode or the skip fire mode where every other ignition is skipped on both cylinders. Some calibrations the timing is adjusted too.

On sportsters and dynas from the factory, only the fuel enrichment and perhaps a little timing is added.

In all cases, when the engine gets dangerously hot, the check engine light will start flashing then go solid. You should try to shut down by the time it goes solid.

The sequence is entirely controlled by the program flashed in the ECM, and TMax may have a program that does something altogether different.

 

Someone want to explain to me how his bike went into harleys overheat mode when:

He is running a Thundermax.

 

Okay, well I guess mine does the enrichment and timing changes only then, because it didn't cut any cylinders off at all...and didn't lower the idle at all.

- Hot Engine
- Light Flashed for about 10 min
- Light went solid
- A few minutes later the RPMs increased significantly and stayed there steady...didn't fluctuate up/down.

I turned it off at that time. Fired back up when it cooled off.

I think the RPMs went up because it was dumping more fuel in to cool off the cylinders, but wouldn't the resulting increase in RPM just heat the motor even more? I don't understand it...