Revving in PARK produces odd shutter/shake 3500 - 4000rpms


searcherrr
11-04-2007, 05:12 AM
Can anyone tell me why our Windstars do this:
http://www.youtube.com/watch?v=jEaBAsniy6U&session=9iTeCZhkwM5oebf2G08nnWIVEsKVZ8UHOpBiGifW-vTuOTnZ404EiRbGswDFsIiyIYA7-SSjY1nKuhLfGSj-D0x7JGUCRfJ4VLUZspuSB2UT-OOXIwQvInN7pHx1vZ32QNeAMeQoBozFbuN1N1NHza2M_9htZQ_ bC4vxop-qg3XjNgFI9GdUtKZCf3-aWcbHvpe-X3sHEH6eHn0CzDIr3W9LDDkQPWSd7c1FzhBPHn3FT96UPKucvi Ci4K83gWQFNJQXX-yuKHT_a63tSoJPinOXNx_mZVNHfMFZsCsag5I=

At second 20 and 22 of this YouTube posted by someone he's revving it and its doing that shutter thing that it does when you rev it up to about 3500 - 4000 rpms..... when you are running it on the road it rarely goes up above 4000, but it has on occassion under hard load. What is the reason for this shuttering/shaking/bobbing of the RPMs when you rev it that high.

After replacing my water pump recently this seemed to get better, but it still does it either GOVERNING or TOPPING out the RPMs you can rev to while in park. I don't know if this means anything at all other than you just shouldn't rev it that high in Park, but I was wondering why our vans do it cause I've never experienced this an ANY other vehicle.

madmatt2024
11-04-2007, 09:24 AM
The vid sounds like the engine is just hitting the rev limiter.
My moms 97 Duratec Taurus does the same thing at 4k rpm when in park or neutral, yet it will rev to the red line if you floor it while driving. Manual transmission cars don't seem to have this, probably because people would complain.

kevink1955
11-04-2007, 09:25 AM
It has a Rev limiter that only functions in Park and Neutral. It's to prevent the engine from blowing up if something gets stuck on the gas pedal. It has no effect in any gear so the engine will rev up to the shift points.

jer1303
11-04-2007, 09:48 AM
Yep, rev limiter. Not real good on your engine to get it up that high with no load from my understanding.

wiswind
11-04-2007, 07:33 PM
I have never thought that it was good to rev an unloaded engine.
I have no expert knowledge to base this on.....just does not seem good to me.
I get uneasy when people post about reving the engine to see when the IMRC kicks in.....as even that is higher than I feel comfortable reving it.
I am not beyond putting the pedal to the metal when driving, and you will feel the boost when the IMRC kicks in.

This is why, I am surprised that they reved the heck out of your engine at the dealership as you mention in another post.
Taking it out and driving it around......staying near the dealership in case the temperature goes up makes much better sense to me.

searcherrr
11-04-2007, 10:57 PM
I have never thought that it was good to rev an unloaded engine.
I have no expert knowledge to base this on.....just does not seem good to me.
I get uneasy when people post about reving the engine to see when the IMRC kicks in.....as even that is higher than I feel comfortable reving it.
I am not beyond putting the pedal to the metal when driving, and you will feel the boost when the IMRC kicks in.

This is why, I am surprised that they reved the heck out of your engine at the dealership as you mention in another post.
Taking it out and driving it around......staying near the dealership in case the temperature goes up makes much better sense to me.

Yeah, agree with you I do..... (me Yoda) on all counts. I was just wondering why it would do that cause I thought it might mean something was wrong and I've never experienced any vehicle with a rev limiter before. What is that anyway? Is that just in the ECM/ECU ??? or is it a physical device?

On the note of what the dealership did at FORD from my other thermostat and/or water/pump thread: I really have to think things would've been fine for the rest of my trip had they not done that crap. What can I do though? If I were to bring legal action on them I'd be fighting with a 157k miles engine vs their big name and big fancy ASE techs. I can see if this happened and the engine was like 40k or even 50k miles I would've probably had a better chance at winning a suit or out of court settlement, but in this case with such high mileage even though I have ALL of my receipts to back up what I've done to the van I have NEVER undertaken internal engine maintenance so they'd probably blame me for not having that type of work performed in the past.

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