Engine running hot.... PCM issue maybe????
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TECH Veteran
Joined: Dec 2001
Posts: 4,117
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From: Ft. Lauderdale, FL, USA
Engine running hot.... PCM issue maybe???? Is it possible that the PCM needs to be reset somehow?
How can I check to see if my fans are coming on when they're supposed to?
Here's my post in the external section:
What on earth can be making my engine hot?
FACTS:
There is nothing stuck up in front of my radiator
The coolant is totally full
The coolant starts to flow after I let it idle for awhile
The fans are working just fine, they were checked thoroughly
My air dam in front is perfect
Symptoms:
If I drive in the city on a hot day (A/C OFF), the temp will go right up to the 210 mark, which in my engine equals about 230 degrees, according to the scanner.
If I put the air on it will quickly go right past the 210 mark and keep on going if I let it. I have to then put the heat on full blast to get it to come back down.
If I'm on the HWY on a hot day the temp will rise to about 215 degrees(scanner). If I put the A/C "on" it will go up to the 210 mark and maybe a little past.
The engine before rebuild never went above the 155 degree mark no matter where or how I drove it with the A/C OFF. With the A/C ON in the city on a hot day the most it would ever go is about 185 on the gauge. It never once saw the 210 mark.
It seems that when I turn the A/C 'on" all hell breaks loose. Because sometimes it'll stabilize and not climb, but as soon as I turn the A/C "on", BAM!!! The needle moves like a widshield wiper.
Could the thermostat be sticking open?
Can a water pump that does not leak, not pump water properly?
Can a failing bearing on the compressor be dragging my engine down when the A/C is "off", and then just totally killing it when its "on"?
Any ideas? I'm getting pissed now
How can I check to see if my fans are coming on when they're supposed to?
Here's my post in the external section:
What on earth can be making my engine hot?
FACTS:
There is nothing stuck up in front of my radiator
The coolant is totally full
The coolant starts to flow after I let it idle for awhile
The fans are working just fine, they were checked thoroughly
My air dam in front is perfect
Symptoms:
If I drive in the city on a hot day (A/C OFF), the temp will go right up to the 210 mark, which in my engine equals about 230 degrees, according to the scanner.
If I put the air on it will quickly go right past the 210 mark and keep on going if I let it. I have to then put the heat on full blast to get it to come back down.
If I'm on the HWY on a hot day the temp will rise to about 215 degrees(scanner). If I put the A/C "on" it will go up to the 210 mark and maybe a little past.
The engine before rebuild never went above the 155 degree mark no matter where or how I drove it with the A/C OFF. With the A/C ON in the city on a hot day the most it would ever go is about 185 on the gauge. It never once saw the 210 mark.
It seems that when I turn the A/C 'on" all hell breaks loose. Because sometimes it'll stabilize and not climb, but as soon as I turn the A/C "on", BAM!!! The needle moves like a widshield wiper.
Could the thermostat be sticking open?
Can a water pump that does not leak, not pump water properly?
Can a failing bearing on the compressor be dragging my engine down when the A/C is "off", and then just totally killing it when its "on"?
Any ideas? I'm getting pissed now
I would look into the thermostat, & the air flow for the radiator/condenser. If the PCM is turning the fans on it's not the problem. The fans can't cool it down? I would go through the mechanical cooling system well first.
the Low cooling fan setting is set at 226, about 210 on the guage. high is 236?.
I'm really not sure how you could of been running at 155* or so as that is even lower than a 160* thermostat. With my 160* thermo i average 180 degrees on the highway. My low fan is set to come on at 184. If I had no fan programming with my converter and a/c on i'd be well up into the 220's. So i'm not sure anything is wrong other than a new thermo and a tune to get the fans on early
Edit: I just read your sig, with that motor
i'm assuming you have every thing done with regards to a thermo and tuning. Sounds like its just to much for the stock radiator 
I'm really not sure how you could of been running at 155* or so as that is even lower than a 160* thermostat. With my 160* thermo i average 180 degrees on the highway. My low fan is set to come on at 184. If I had no fan programming with my converter and a/c on i'd be well up into the 220's. So i'm not sure anything is wrong other than a new thermo and a tune to get the fans on early
Edit: I just read your sig, with that motor
i'm assuming you have every thing done with regards to a thermo and tuning. Sounds like its just to much for the stock radiator 
First off with all the money you just put into the engine you would think they would set the **** a little lower and second this is where your problem may lie. Check to make sure the coolant hose comming form the TB is on the bottom connection on the radiator. If they are swapped this will cause the car to run a little hot.... Ask me how i know?
