Stalling after header install
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
EFI self adjusts continuously(unlike a carb) and the system has more than enough adjustment range to compensate for an exhaust system, so the motor will not run lean or rich as long as the the system is functioning normally.
Freshman User
Joined: Aug 2012
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try unplugging the vacum line from the EGR valve, my 302 does the same thing when EGR vacum is connected... there is also a sensor on the the bottom of the throttle body that i had to replace and it helped a lot.
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Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
Little update on this scenario.
Seems over the last couple weeks, the computer must have reconfigured itself enough that now it starts and runs great. Doesn't stall or stumble when coming down from high idle after starting cold. Seems back to normal and I haven't touched a thing.
Stranger things have happened.................
Seems over the last couple weeks, the computer must have reconfigured itself enough that now it starts and runs great. Doesn't stall or stumble when coming down from high idle after starting cold. Seems back to normal and I haven't touched a thing.
Stranger things have happened.................
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
When the battery is unplugged the computer loses any stored codes but also loses everything it has learned about the engine in terms of fuel and spark management, so it has to start from the base calibration it was programmed with and build it up over time. The behavior you saw is normal and will be more noticable the more the engine is modified from stock, my truck runs really bad after a battery disconnect with the cam and big empty exhaust on it, but it doesn't take too long before it settles down again.
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Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
Ya, I figure it would relearn, but kinda strange how I just realized it was running good and not having the issues it had a few weeks ago.
Buddy used to run his '87 Mustang when it was new, if he screwed with it before taking it to the track it would not run as well til he flogged on it a few times. Then it knew what to do. Typical.
Buddy used to run his '87 Mustang when it was new, if he screwed with it before taking it to the track it would not run as well til he flogged on it a few times. Then it knew what to do. Typical.
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