Thermostats—- 160* vs 187*

[Jonesy92]

I lied. Scanner is in The wife’s car. -_-

 

[Jonesy92]

So, I finally narrowed it down. I picked up the last in stock 161* degree thermostat from the lock auto parts store, and have been driving for about a week with no hesitation, no lean codes, no CEL’s, and better yet, no reduced engine power mode any longer.
I did install a fuel pressure gauge into the a-pillar from Glow Shift to watch the pressure while I was driving and pressure seems to be about 57/59 at idle.
Now onto the replacement of the control arms, brake pads, tie rods and ball joints

 

[rockola1971]

So, I finally narrowed it down. I picked up the last in stock 161* degree thermostat from the lock auto parts store, and have been driving for about a week with no hesitation, no lean codes, no CEL’s, and better yet, no reduced engine power mode any longer.
I did install a fuel pressure gauge into the a-pillar from Glow Shift to watch the pressure while I was driving and pressure seems to be about 57/59 at idle.
Now onto the replacement of the control arms, brake pads, tie rods and ball joints

That 161 deg thermo didnt fix the problem. It covered it up. Both my 5.3L(2) and 6.0L K chassis normally run around 200deg or so. They are designed to do that. You have something else going on there. DO you even go into closed loop at 161deg?

 

[Jonesy92]

I’m not sure what you mean? Running without the thermo dumping new into the system?

 

[rockola1971]

I’m not sure what you mean? Running without the thermo dumping new into the system?

You running at 161 deg may keep your PCM from going into close loop, so you are in open loop. During open loop the PCM ignores most of your sensors values and uses tables of instructions to run your engine that are defaults until it is warmed up to around 180-190. So no fine tuning and getting max efficiency out of your engine. Your open loop situation is likely causing the PCM to ignore a sensor that is bad because it was forced to by the 161 deg thermostat. When you had in the correct thermostat the engine was warming up enough to go into closed loop and your potential bad sensor reared its ugly head and the PCM did not ignore it. All of the codes you saw were clues to the actual problem. All of our era K and C Chassis run around 200deg normally, there isnt anything special about your 4.8l,5.3l,6.0l that would cause it to be different.

 

[MassHoe04]

Makes sense @rockola1971

I thought this was an interesting note...

"Gasoline vaporizes at 140 degrees if you raise the temperature of the gasoline to say 200 degrees the gasoline will vaporize faster in the combustion chamber resulting in a better burn and improved gas mileage."

Taken from this article.

Double Your Gasoline Mileage Now and Improve our Economy

Its my opinion that the current economic conditions were brought on by high gas prices. I believe if we can consume less fuel we can stabilize the price of gasoline and our economy. If we do nothing we will have contributed to our failing economy. Here is a solution we can implement right now...

www.science20.com