bad idle. DP failure.

[fixkick]

this is one odd example of how idle can fail.
the mech put vacuum hoses on the engine doing service.
he failed to mark them.
or the VSV fails.(stuck open, more than one way possible)

in this example the EGR hoses were connected to the DASHPOT. ("DP"
seen here, failing, it must never move, like this, on any running engines
running over 30seconds.

http://jeepdied.com/look/alien-stuff/DP-...ailure.MOV


in addition to this, The DP is not calibrated, i see the gap is wrong too.
and both failures, (hose and gap)
Are wrong,and this
causes the ECU to go nuts. (very odd fast idle modes, that do not show up in a real scan too, expect , "target" parameter for idle is wrong)

hope this saves someone from this horror....
he, nor his mechanics, could figure it out and 3 throttle bodies later, and more parts swapped, and it still fails, until 1 video is sent out.
bingo, wrong actions on DP.

this violates the FSM rule of 3 to 30 second, startup DP actions.
The ECU we think tries to (secret mode) go to a virtual DP mode.
it sees it fail, and tries to emulate the malf'ing, DP.
and fails to set a DTC for this,,,