: Limp Home Feature?

06-19-04, 08:41 PM
When your Northstar runs out of coolant there is the Limp home feature tha lests you go 50miles at 50mph with out coolant. How does this thing turn on or know when to turn on or is it done manualy.

Sorry to lazy to check owners manual:yawn: .

06-20-04, 05:29 AM
im not 100% absolute on this, but it seems since it has a coolant sensor., it will turn on limp mode when it detects a low coolant signal, sorry for stating the obvious

06-20-04, 05:43 PM
Thats what I was thinking, thanks a load.

06-20-04, 08:01 PM
Actually it seems to be temp related.

At 2?? degrees it shuts the air conditioner off and tells you it is doing it.

At 2?? degrees it will kick into "limp home" mode and tell you to shut the engine off immediately to avoid further damage.

I know from experience...:crying: .

Have fun,

Anthony Cipriano
06-20-04, 11:16 PM
The limp home feature is automatic and is based solely on temperature from the coolant temperature sensor. The coolant temperature sensor is located in the head so that if the system starts to go dry the sensor is uncovered very quickly. Once the coolant sensor is dry it'll pick up heat from the exhuast port wall adjacent to it and climb in temperature rapidly. When the PCM sees the coolant temperature sensor climb to around 132 celsius it triggers the limp home logic to alterately turn off the fuel to 4 cylinders so that those 4 cylinders can pump just air and cool themselves. After an interval the other 4 cylinders cut out to cool them. It's very effective at keeping the overall engine temperatures cool enough in a coolant loss situation to protect the engine from damage.

07-16-04, 08:08 PM
Does it turn back on after a while.

07-16-04, 09:37 PM
If the temperature goes up again, yes.

Anthony Cipriano
07-17-04, 12:46 AM
Does it turn back on after a while.

Do you mean does the engine go back to 8 cylinder operation after awhile? As long as the engine is overheated it'll stay in the limp home mode. If the engine is shut down and cools off the engine will resume 8 cylinder, normal operation automatically. If it overheats again it will go into limp home mode. If the engine is shut down and the problem causing the overheat is resolved the system will automatically revert to 8 cylinder operation and stay that way - until the next time it overheats.

07-17-04, 12:49 AM
Damn Anthony.. you're up late man :) .. just saying, i love this engine. Even in my 1993 i'm continousy impressed by all the though put into it.