04-01-2018, 10:43 AM
yes, that will happen, and for sure with vacuum leans, so one closed it too much to hide the leak and fails.CCW is closed TV.
just screw it back to where it was, counts.
its just stop screw just like all CARBs had.
the vacuum lines pinch them if rpm drop or surge ends, you have line in the line or the object on the end of the line is leaking.
the map sensor line must be hand inspected, and both nipples on both ends not packed in gunk or the filter on that line
the EGR hoses, pinch them.
inspect the DASH pot first make sure it retracts after starting car, it MUST this is first, first.
the ISC can fail too, it can stick open ISC is that thing on left facing TB, 2 wires, looks like cyclinder, its valve that controls idle.
it has gaskets that can leak. air.
cracked PCV hose.
all hoses to the induction plenum (area below TB is that) causes a huge fast idle speed, and surge.
it can be overwelming the possible pathes for leaks, even the TB gaskets in the middle can leak, 91 to 95, Im not sure on 89/90
The TB body has air hole pathes inside, for the ISC and IAC, that can leak.
the IAC in the base of the TB can fail, if its water hose is clogged, this causes it to run too cold and not go past 150f water temp there, and the valve sticks open
sorry I forgot to say 1st the water temp most be 180f or more, hot, not 140f, or the EFI locks up in cold running mode, and goes mad.
one more trick is find a way to unplug the ISC 2 wires, on 91 this kills the injector, but i forget on 89 if it is 2 pin connector, or shared. it is 2 wires for sure.
if the ISC is unplugged, rpm goes to like 400 hot. engine shacks.
this is normal, if RPM stays high, there is a vacuum leak. hot. all comments by me are hot engine 180f+
cold RPM are bag of worms #2. LOL
just screw it back to where it was, counts.
its just stop screw just like all CARBs had.
the vacuum lines pinch them if rpm drop or surge ends, you have line in the line or the object on the end of the line is leaking.
the map sensor line must be hand inspected, and both nipples on both ends not packed in gunk or the filter on that line
the EGR hoses, pinch them.
inspect the DASH pot first make sure it retracts after starting car, it MUST this is first, first.
the ISC can fail too, it can stick open ISC is that thing on left facing TB, 2 wires, looks like cyclinder, its valve that controls idle.
it has gaskets that can leak. air.
cracked PCV hose.
all hoses to the induction plenum (area below TB is that) causes a huge fast idle speed, and surge.
it can be overwelming the possible pathes for leaks, even the TB gaskets in the middle can leak, 91 to 95, Im not sure on 89/90
The TB body has air hole pathes inside, for the ISC and IAC, that can leak.
the IAC in the base of the TB can fail, if its water hose is clogged, this causes it to run too cold and not go past 150f water temp there, and the valve sticks open
sorry I forgot to say 1st the water temp most be 180f or more, hot, not 140f, or the EFI locks up in cold running mode, and goes mad.
one more trick is find a way to unplug the ISC 2 wires, on 91 this kills the injector, but i forget on 89 if it is 2 pin connector, or shared. it is 2 wires for sure.
if the ISC is unplugged, rpm goes to like 400 hot. engine shacks.
this is normal, if RPM stays high, there is a vacuum leak. hot. all comments by me are hot engine 180f+
cold RPM are bag of worms #2. LOL
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