Pcm ?
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Elder User
Joined: Feb 2004
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From: Indiana
Pcm ?
Is there a certain coolant temp that the PCM goes by before going into closed loop?
I have a 2000 ford winstar (3.8 L) that I had a MIL issue and was using a scan tool to gather info on when the code was actually being tripped. After checking the engine when it was cold (After sitting over night) it only stayed in open loop for about 30 seconds or less (the coolant temp was well under 100 degrees when it swithed to closed loop) . Is this a timed event or is it acutally suppose to stay in open loop longer? Most of the stuff I've read states it should stay in open loop to a certain temp before switching to closed loop.
I've corrected the problem that was causeing the MIL to come on and the van runs better than it has in a long time.
I have a 2000 ford winstar (3.8 L) that I had a MIL issue and was using a scan tool to gather info on when the code was actually being tripped. After checking the engine when it was cold (After sitting over night) it only stayed in open loop for about 30 seconds or less (the coolant temp was well under 100 degrees when it swithed to closed loop) . Is this a timed event or is it acutally suppose to stay in open loop longer? Most of the stuff I've read states it should stay in open loop to a certain temp before switching to closed loop.
I've corrected the problem that was causeing the MIL to come on and the van runs better than it has in a long time.
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From: Virginia
The oxygen sensor itself needs to reach 600 F before it will work. From what I can gather the computer looks for an actual readible signal from the oxygen sensor before it will go in closed loop. In 1986 they went to the heated oxygen sensor to keep the sensor hot enough during idle conditions. They explained the oxygen sensor would actually cool off during extended idle and the computer would drop out of closed loop. The engine would certainly be hot enough during those conditions, so it must not use the coolant sensor as it's only decision maker for closed loop.
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Elder User
Joined: Feb 2004
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From: Indiana
Thanks Franklin that explains alot. Just got a scan tool to help figure out what was going on with our van and it has a lot of options to it that I'm still trying to figure what they all mean.
