Hesitation/stumble in transition from open loop to closed loop
Hesitation/stumble in transition from open loop to closed loop My car is a recently converter 93 to 94 car (engine harness/pcm, maf, heated o2's etc). Car overall runs strong, but has a stumble when it goes into closed loop. The car chokes, and goes to die, whether you're driving or parked. It lasts a few seconds then the car runs great the rest of the time. It has new o2's (Denso's), maf checked out okay, and most things sensor-wise on the car are brand new (within a year old). Went through the tune with my tuner and there's nothing wrong in that department. I have no clue what it could be, can anyone throw me some ideas? Thanks!
TECH Apprentice
Joined: May 2010
Posts: 333
Likes: 1
From: Arkansas
I've spent month's trying to track this issue down. What is your target idle speed? And what about your car, cam? forged pistons? What else? Next time you drive it get it at operating temp in closed loop. Turn it off and then restart it. if it does not stumble now when it goes from open to closed loop then at the point when you go from open to closed loop with a cold engine your 02's may not be hot enough starting with a cold engine. I had this problem with bosch's. I think I did anyway
