Thermostat modification

[zippy]

for the temp itself, but it also reads maf readings and a few others to set the code.

[SuperSport]

I use to get a check engine light in my 8.1L after i drilled 3 holes in the thermostat. I had my friend scan it at the dealer and he said it was running at 167 degrees, but after a while it just went away. I think it just took time to learn.

[MustBBrent]

I use to get a check engine light in my 8.1L after i drilled 3 holes in the thermostat. I had my friend scan it at the dealer and he said it was running at 167 degrees, but after a while it just went away. I think it just took time to learn.

I think you may have SCARED it (the PCM, that is.)

[deezel]

pirate, my guess agrees with zippy... see if you get this code:

DTC P0125 ECT Excessive Time to Closed Loop Fuel Control

 

To fix this, you either need to plug up some of those holes in the tstat, or adjust the tuning. With a PCM editor you could probably reduce the closed loop enable temperature by 5-10 degrees and get rid of this code.

[ChevyHighPerformance]

On the LS1, the delay time to set P0125 is from 2 min 20 sec to 22 min 30 sec. This is the time delay for the ECT to reach 93 F. This depends upon startup ECT, IAT, and vehicle speed. It may be better to shim the piston in your stock tstat to 160 instead of drilling holes. The stock LS1 tstat is ~$16 to get one to modify.

[BenKey]

for the temp itself, but it also reads maf readings and a few others to set the code.

Zippy, you're getting way too deep on me. All I was saying is there is no way, unless a wire is attached to it, that the PCM will know whether or not the thermo is "physically" open.

 

I was not getting deep and talking about whether or not it would be using multiple data points to make a conclusion.

[zippy]

for the temp itself, but it also reads maf readings and a few others to set the code.

Zippy, you're getting way too deep on me. All I was saying is there is no way, unless a wire is attached to it, that the PCM will know whether or not the thermo is "physically" open.

 

I was not getting deep and talking about whether or not it would be using multiple data points to make a conclusion.

lol, sorry. didn't mean to go into it like that.

there is no way for it to physically know anything about the thermostat.

[pirate#3]

pirate, my guess agrees with zippy... see if you get this code:

DTC P0125 ECT Excessive Time to Closed Loop Fuel Control

 

To fix this, you either need to plug up some of those holes in the tstat, or adjust the tuning. With a PCM editor you could probably reduce the closed loop enable temperature by 5-10 degrees and get rid of this code.

Cool, thanks for the info. I reset the pcm and it hasn't thrown me a code in the last two days. I'll probably pull the thermostat and fill two of the holes until I buy some sort of tuning.