This is topic will a 180* thermostat cause this problem? in forum Tech Talk at Northern California Ford Owners  .


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Posted by yesIdid (Member # 58) on :
 
will a 180* thermostat prevent my car from going into closed loop if engine temps are too low?

i have a suspicion my car's not always in closed-loop; we had issues with it staying in open loop on the dyno a few weeks ago.

[worship]
 
Posted by Cobra5.0JEEP (Member # 1482) on :
 
quote:
Originally posted by yesIdid:
will a 180* thermostat prevent my car from going into closed loop if engine temps are too low?

i have a suspicion my car's not always in closed-loop; we had issues with it staying in open loop on the dyno a few weeks ago.

[worship]

no, i believe closed loop only lasts for a minute to a minute and a half unless theres some senor telling it not to do so. The thermostat won't effect it.
 
Posted by BlueOvalRacing (Member # 1531) on :
 
Sorry Dana, but an stuck open, missing, or colder than stock (192 degrees) thermostat can affect closed loop operation. If the pcm does not see the engine temp come up to around 192 degrees, it will keep the fuel pulsewidth up (rich) thinking that the engine is not warmed up. That will not allow the o2 sensors to switch rapidly, therefore causing the pcm to stay in open loop. The o2 sensors have a built in heater, but that is only used on start up to heat the sensors up to keep them from fouling, and to help control the fuel delivery on start up.
 
Posted by mtbaughs (Member # 4052) on :
 
Maybe a 160 degree stat will keep the car in open loop but a 180 degree stat never will unless it's stuck open. Things to check are, the car running overly rich from improper fuel calibration, bad O2's or a mis-calibrated MAF

[ August 09, 2004, 06:14 PM: Message edited by: mtbaughs ]
 
Posted by yesIdid (Member # 58) on :
 
changing-ou the t/stat is easy; i'll try that first
 




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