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Testing 3-wire coolant temp sensor?
Topic Started: Oct 30 2012, 08:26 PM (3,540 Views)
going88mph
New Member
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Does anyone know how to test the 3-wire (later) coolant temp sensor? I tried checking each pin with respect to battery ground, and I get nothing. Car has a hard time starting cold, runs for 2 minutes, and then shuts down where it can't be restarted unless you floor the pedal.

Thanks.
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Tubablake
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That doesn't sound like a coolant temp sensor issue
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going88mph
New Member
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What does it sound like? Injector is new. Tps is new. Cam sensor is new. Cap/rotor/plug wires are new. It appears to be flooding badly. When i rev it up, it drops back down and stalls, spewing oil-thinned-with-gasoline from the valve cover vent hose (air filter assembly removed). Thought maybe a dead cts was making it run extra rich.
Edited by going88mph, Oct 30 2012, 10:06 PM.
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mwebb
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FOG

if the vacuum to the MAP sensor is not correct
MR MAP sensor will correctly report hi load and MR ECM will open injector pulse width to create
rich condition

if the cat converter is clogged , for the same reason , vacuum will be incorrect , the same condition will occur .

having said that
you can use a scan tool to view coolant temp to verify your
theory

and you can also view MAP or Intake vacuum
MAP = manifold absolute pressure ,
MAP + intake vacuum = barometric pressure / local ambient baro

test , do not guess
Edited by mwebb, Oct 31 2012, 12:24 AM.
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clarkdw


Quote:
 
spewing oil-thinned-with-gasoline from the valve cover vent hose


Before you spend any more money on the shotgun approach do yourself a favor and do a compression test. The above is a classic sign of severe blowby. Severe blowby will result in poor vacuum, poor vacuum will result in rich running.

Follow the link to get comparable results.

How to compression test
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going88mph
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Update: Hooked up code reader. Threw p0134. Replaced o2 sensor and we're back to the races!!! This explains why it would start and run for two minutes (open loop mode).
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mecevans
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Also change that oil ASAP, before it causes engine damage.
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