Rev limiter ? 08 4.6 Ltd? Governor ???

[pjw73nh]

UP here in New England we're in the first REAL cold snap of the 2013 - 2014 winter season.

This AM I left my car running for about 40 mins, with the heater on, and when I came out, car was not as warm as I would have liked. I attributed this to low idle and not enough coolant circulation...

So when I got back in the car I revved the engine a bit to circulate some coolant. It stopped revving at 3500 exactly. Yet when I put it in gear and drove, I was able to punch it, get it to downshift, and get it up to 6000+ rpm.

Does this engine have a governor? and/or does it only engage at low temps?

Tnx.

 

[Flag Gibby]

No it is just the torque converter stall speed. As far as the cabin not warming up very well, it could be due to your thermostat opening too early and not letting the engine reach proper operating temperatures. It really should have been hot in the cabin if you had it idling for 40 minutes.

Note: I overlooked the Park/Neutral statement regarding the OP... The correct answer is Yes there is a Park/Neutral rev. limit. It just happens that the stall speed and P/N rev limit are the same.

 

[Explorer0204]

UP here in New England we're in the first REAL cold snap of the 2013 - 2014 winter season.

This AM I left my car running for about 40 mins, with the heater on, and when I came out, car was not as warm as I would have liked. I attributed this to low idle and not enough coolant circulation...

So when I got back in the car I revved the engine a bit to circulate some coolant. It stopped revving at 3500 exactly. Yet when I put it in gear and drove, I was able to punch it, get it to downshift, and get it up to 6000+ rpm.

Does this engine have a governor? and/or does it only engage at low temps?

Tnx.

In both neutral and park they have a rev limiter of 3500. Don't really know why but they do. My 02 didn't have it the 04 does. Even my friends 04 mustang does as well.

 

[Flag Gibby]

Guys, it really does have to do with the torque converter stall speed... every automatic transmission has one it just happens to be that Ford uses one that is set to around 3500 RPM on these vehicles. See here for a better understanding: http://www.bankspower.com/techarticles/show/10-understanding-stall-speed

 

[mreed112]

Torque converter stall speed has nothing to do with engine rev limiting in park and neutral. I believe that the reason for limiting engine rpm in neutral (and P) is to reduce impact loading to the transmission by preventing revving the engine to 6k and moving the shift lever from N to D.

 

[Flag Gibby]

True, I overlooked that detail because it just happens that the torque converter stall speed on this generation is 3500 RPM; at least that is what I recall from the last time I checked it (or was it 2500??).

So I was wrong, my original statement should have been Yes there is a Park/Neutral rev limiter because high RPM's on an engine not under load is hard on the internals; it also helps save the transmission as you mentioned mreed.

I think that I am going to take a break for a couple of days from here... making too many stupid mistakes due to overlooking details.