Quote:
|
Originally Posted by TurboLS1Camaro
Ok.. More info on this..
Changed the plug wires back to the originals. Same issue. Put the original plugs back in.. Same issue. Put the new wires on the original plugs, same issue.
I am assuming GM has this set up kind of like my 2001 Camaro in regards to timing maps and fuel cells..
At cold fire up, it should be in open loop right? I think my Camaro is in open loop under 145* F. Once above 145* it goes in to closed loop and wont enter open loop until at WOT.
With the Century, at cold, open loop it runs great. No miss and no bog. As soon as it gets warm and goes in to closed loop it starts to miss under load. Perhaps it is seeing some false knock and slipping into limp mode?? Again, it is yanking a ton of timing (9* at WOT). It should be going from closed loop to open loop over 70% throttle if like my Camaro.
Any more suggestions? What could be causing this false KR if that's what it is..
I can log with A-tap and post it in to an excel spread sheet if any of you would like to view it. Give me the perameters you would like to see and I'll post a link to it. I would assume you would want to see:
KR
Timing
TPS%
O2
RPM
Gear
MAF
AIT
Anything else?
|
I agree with your analysis of open and closed loop ECU operation. Approx. at what rpm does the miss start? In closed loop FI system is dependent on 02 sensors primarily the one before the CAT. Is it possible the mechanic damaged the 02 sensor when changing the aft plugs and wires?
How much load is on the engine when the miss starts? For example how close to WOT. Did you check the MAF sensor. Is it clean? Have you tried disconnecting it to see if there is any difference for troubleshooting purposes. Hows the fuel system pressure at the rails? Other possibility ICM/coil packs.