Is JJ's chip what you had in your brothers truck when it blew?
This is the Cecil track day thread.

The computer in these trucks are more complex than I realized. I stuck in a chip last weekend and was running 10.5:1 air fuel ratio WOT. Then 600 miles later I was running 12.5:1 air fuel ratio WOT. I shut off the battery switch for 10 minutes now it is running 10.5:1 again. TR6's with 15psi boost from a KB and plugs look good. What works on one truck doesn't mean it will work perfect on another.

 

That is very interesting...

Can the PCM overide the settings in a chip after time? Something similar to the learning curve that a stock PCM has for driving styles/habbits. I have heard rumors that the '01/'02 PCM might actually do this with a chip, but I have never seen any proof.

Easter - not trying to stir anything up, but can you post what brand chip you were running when you noticed this?

 

I had Jim reburn my superchips for my truck in Commerce this weekend. We datalogged it and at WOT my FJO wide band O2 would read 10.5:1. I drove it back to Nashville and then to work in Clarksville the next day(500 miles or so). I noticed on the drive home from work Monday that the air fuel was now reading 12.5:1 at WOT. I guess the pcm was over riding the chip? I also installed TR6's instead of the IT24's that were in the truck. Anyway I called JIM who said to disconnect the battery. I did and the air fuel went down to 10.5:1 at WOT...
BTW, Jim told me that it would probably do this and that it may be due to the fact that the computer was compensating for all of the fuel it was getting with the bigger fuel pumps.

 

I guess that most people will not be able to compare their L with yours since you are heavily modded...

Regardless, it is very interesting.

If the PCM overides the settings in the chips, then that might explain how there are so many blown motors - especially the '01s.

 

 

 

That is interesting.

How does the computer know you have bigger fuel pumps?

Have you jacked up the fuel pressure beyond spec?

LSOS KIUJ TWTU

 

I am suprised that there has not been much input on this....

Someone has to know if the PCM can overide the settings from a chip...

 

I don't know how the computer works. All I know is what I see from the gauges and autotap. For example I disconnected the battery last night. This morning I drive around and don't get on the throttle hard for about 20 minutes. Long term fuel trims stay at around zero even at 50/70 mph and fuel pressure is around 32 and air fuel is 11.0:1. I go WOT a couple of times and now fuel trims are around -15 for cruising and fuel pressure is 37psi and air fuel is up to 14.5:1.

I was just posting what I have seen.

 

Most of the guys in my club dissconect the battery after every run at the track to restor the chip to optimal settings.
I know my truck seems to run a lot better every time i reconnect the battery after doing soem work on it.
I might just do it every night know and see what happens.
SEE YA!!