PO128 what the f...?

So, I have had my Preditor 91 octane tune, 180 stat and reset fan temps in my car since April. No problems, no codes...until about two weeks ago. Started throwing the PO128 code, temp too close to stat as I understand it.

I figure it is because of the car first experiencing cold weather...in the teens some mornings. I carry my scan tool, and reset and erase the code. This happened about every other day. Now, today it is over 50 degrees, and it did it again! So, I quess it is not due to cold weather, but I put about 7,000 miles on it before I see the code for the first time. And I passed emissions last week after having to erase the code twice before I went in.

Any ideas? I can't understand wnat is making it do this after all that time. Having to erase the code every other day is a pita.

 

In colder weather, let the car warm up to at least 110*'s before taking off. This should do it?

 

x2...... if i do not let mine warm up when it is below 40, the damn thing will not shift out of 1st gear!!!!lol

 

I've never had that problem, shifts fine

it always throws the code after about 10-15 min running with temp over 170

never gives code on start

thanks, any other thoughts on it????:help:

 

that's because the pcm will not throw the code til iy sees a complete heat cycle on the coolant temp sensor. those code comes up because the motor doesn't come to a high enough temp within the time frame. the time frame doesn't start til the pcm sees movement from the car.

 

Right, but a 180 tstat shouldn't be any different than a stock tstat for that. The threshold is somewhere between 167 and 176 (or 173) or something close to that. Unless that 180 tstat is starting to open early it shouldn't make any difference at all from stock with respect to that code.

The guys running a 170 tstat might have problems but you shouldn't see any with a 180.

1) I assume you have your fans set to come on somewhere 180 or higher?
2) Your tstat could be sticking open?

You might want to take the tstat out and put it in a pot of water on the stove with a meat thermometer and make sure it's opening and closing correctly and at the right temps.

 

in subfreezing weather i have herd of this happening on stock t-stats.

 

I was getting that code with my 170 Tstat..... I had Diablo turn off the warning light since I had no intention of changing it........ I also have a digital engine temp gauge some Im not worried