Cruise control overrevved!

[Rrrockhound]

I was on one of those high-speed roads with occasional traffic lights and when the light turned red, I shifted into neutral in preparation to stop. Didn't realize the cruise wouldn't disengage in neutral and the engine spun into the stratosphere! I don't know why I didn't just think to touch the brake pedal, but in full panic mode, I killed the ignition and coasted down. On restart, everything ran OK, no nasty noises, and the engine runs fine now. I assume there's a rev limiter, and if I hit redline, it wasn't for more than 1 second. Anyway, is there anything I should do or check at this point, like the timing belt tension? The timing belt has probably less than 1K miles on it now.

[Techno Duck]

As long as it wasnt a downshift, the rev limiter should have prevented any damage being done to the engine. If you downshift and over rev the engine, the rev limiter dosent do anything.

I wouldnt worry about it.. i have tapped the rev limiter on more than a few occasions (autocross). Still running strong... ::Knocks on wood::

You should have your timing belt retensioned soon anyhow.. supposed to be between 1000-1500 miles for a new belt.

Besides, its good to give the car a good Italian tune up every once in a while.. need to burn off some of that carbon buildup you know.. .

[Dougster]

Interesting...
Mine only engages ABOVE 80 MPH...

[Zero10]

Mine will engage at 20mph if I use it, but it cuts out as soon as I press on the clutch or the brake.
Sounds like your clutch switch is shot.

[AaronM]

Originally posted by Zero10
Mine will engage at 20mph if I use it, but it cuts out as soon as I press on the clutch or the brake.
Sounds like your clutch switch is shot.

Properly functioning 944 cruise control should re-engage when you take your foot off the clutch pedal.

[Rrrockhound]

Originally posted by AaronM
Properly functioning 944 cruise control should re-engage when you take your foot off the clutch pedal.

I think that's what happened...the cruise disengaged when I hit the clutch pedal, but re-engaged when I shifted into neutral and took my foot off the pedal. I checked the owner's manual and it warns against shifting into neutral with the cruise on. D'ohh! I didn't expect it, because my '83 Volvo would disengage if you shifted into neutral, so I assumed a Porsche would, too.

[Jer944]

the person that had the car disconnected mine cant wait to find out why once the motor is hooked back up

[Porsche-O-Phile]

LOL!!! There's a rev. limiter. Assuming it's working properly you've got nothing to worry about.

Just a heads-up, in a lot of states it's actually illegal to coast in neutral. In any case, it really isn't the best driving technique.

[AaronM]

Originally posted by Porsche-O-Phile
Just a heads-up, in a lot of states it's actually illegal to coast in neutral. In any case, it really isn't the best driving technique.

Agreed. I usually just leave it in gear until I've slowed to idle speed in that gear, then hold the clutch down until I'm completely stopped, shifting into 1st just as the car gets stopped.

[Brando]

How can they prove you were coasting in nuetral, when you actually could have been in gear with the clutch in? oooooooo...

[bearone2]

Originally posted by AaronM
Properly functioning 944 cruise control should re-engage when you take your foot off the clutch pedal.

yes it should but he stated he put it in neutral with cruise engaged which puts the motor in a severe no-load condition.

not sure i want to put all my faith in the overspeed limit capabilities which is protection in a loaded condition.

87951

[AaronM]

Originally posted by bearone2
yes it should but he stated he put it in neutral with cruise engaged which puts the motor in a severe no-load condition.

not sure i want to put all my faith in the overspeed limit capabilities which is protection in a loaded condition.

87951

Then don't put the car in neutral and let off the clutch with the cruise control on.

The system functioned as designed. The fault was in the driver.

[NKN84944]

Haha yeah I kinda did the same thing before in an old Fold conversion van. The cruise control got stuck on at 70mph, and I couldn't turn it off by pushing the brakes or the button. I was left with the only choice of throwing it into neutral, at which point I thought my engine was going to explode like you did. I also killed the engine, but that made it very difficult to maneuver the beastly vehicle around the traffic jam that I was quickly approaching

I would think that everything would be fine with your engine, assuming that your rev limiter is functioning properly. Definitely won't be making that mistake again now will you

[Eldorado]

why would it be illegal to coast?

[AaronM]

Originally posted by Eldorado
why would it be illegal to coast?

Because it stops engine braking and also makes it difficult to speed up quickly if that is needed.

[Rrrockhound]

Originally posted by AaronM
Then don't put the car in neutral and let off the clutch with the cruise control on.

The system functioned as designed. The fault was in the driver.

I can't believe new vehicles would be designed this way, and like I said, my '83 Volvo wagon (god, I loved that car!) would shut the cruise down permanently if you hit the clutch, so I may just look into splicing the clutch shut-off switch so it's on the same circuit as the brake pedal shut-off switch, to make sure this never happens again. Or I could re-train myself not to shift into neutral until stopped... Hmmm...re-wire or retrain self? Better re-wire.

[Zero10]

I tested mine, and it doesn't re-engage when I release the clutch, in gear or in neutral.
Either somebody already tweaked the clutch switch wiring, or mine's just plain broken