[Gmecm] Tracker TBI

[Jason McNamara]

First thing that comes to my mind is the coolant temperature sensor.  Usually when they fail the computer thinks the engine is colder so adds more fuel.  
   
  I've had problems like that with many cars, although not as bad.  rough running in open loop, sluggish.  Hook up the scan tool and see 10-15 degree lower temp from the sender then what the engine is at, pop in a new coolant temp sensor and no problem.
   
  Worst I ever saw a CTS fail was on the formula sae car at school.  We had problems with it flooding out while trying to start it.  Hooked the lap top up to it, the ecu thought the engine was at -200F in the middle of summer in Ohio.  Since we were out testing about 30 miles from the nearest parts store we just reset some of the cold start values to get it running.  Of course it wouldn't run right after that (bogging, lack of power) so we reconfigured the ecu to ignore the CTS while running, just had it use throttle position and MAP.
   
   
  Cowen <captain_krill at yahoo.com> wrote:
    
I also noticed last week we had a day down to -11
Celsius, and when I started it, it was so rich it ran
on 3 cylinders for 10 seconds - then it went to four,
as normal. I'm guessing it was very rich in open
loop, then when the HO2S warmed up, it was fine.
--------------
  So, I'm guessing it's rich in open loop. What can
cause that to happen suddenly, in a totally stock
vehicle with no messing around?? Thanks for any
guesses!

Duncan