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cold start? whats wrong with the idle

  • Thread starter Thread starter D347643
  • Start date Start date Sep 6, 2004
D

D347643

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Jan 28, 2003
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portland, OR
Sep 6, 2004
#1
  • Sep 6, 2004
  • #1
when i start my car up in the morning (or whenever its cold) it wont idle worth **** and it wont even flare up and idle high. shouldnt it idle high? the engine surges like crazy. anyone have any ideas?

thanks

Drew
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
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Sep 6, 2004
#2
  • Sep 6, 2004
  • #2
codes?
clean the iac and check ECT and ACT sensor values (they could be out of calibration but not out of spec - no code).
good luck.
 
D

D347643

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Jan 28, 2003
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Sep 6, 2004
#3
  • Sep 6, 2004
  • #3
anybody have a link to a resistance chart for the temps sensors? act, whats that?
 

HISSIN50

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Sep 6, 2004
#4
  • Sep 6, 2004
  • #4
Jrichker has posted the values for us before. try searching (im on dial up and not having luck) for the values from him. he refers to them as ECT and ACT sensors - standing for engine coolant temp sensor and air charge temp. good luck.
 
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White03Mach

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#5
  • Sep 6, 2004
  • #5
Check for codes and possibly a vaccuum leak somewhere. If it is, and smooths out when it gets hot, the heat causes the gaskets to expand and seal closing off the vaccuum leak. Hope this helps!!
 
D

D347643

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Sep 6, 2004
#6
  • Sep 6, 2004
  • #6
well the vac doesnt change cold or hot, it just surges really bad when its cold. arent our cars suppose to idle high when cold?
 

HISSIN50

"How long does it take to get help in here?
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Nov 29, 1999
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Sep 7, 2004
#7
  • Sep 7, 2004
  • #7
another one - when did you last clean your IAC? any load issues (i.e. the idle bogs when the a/c is on, etc)?

good luck.
 

jrichker

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#8
  • Sep 7, 2004
  • #8
ECT & ACT values as requested...

Code 21 – ECT sensor out of range. Broken or damaged wiring, bad ECT sensor. Note that that if the outside air temp is below 50 degrees F that the test for the ECT can be in error.

The ACT & ECT have the same thermistor, so the table values are the same

ACT & ECT test data:

Use Pin 46 on the computer for ground for both ECT & ACT to get most accurate readings.

Pin 7 on the computer - ECT signal in. at 176 degrees F it should be .80 volts

Pin 25 on the computer - ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer.

Voltages may be measured across the ECT/ACT by probing the connector from the rear. Use care in doing it so that you don't damage the wiring or connector.

Here's the table :

68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61

Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms
 
D

D347643

Banned
Jan 28, 2003
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portland, OR
Sep 7, 2004
#9
  • Sep 7, 2004
  • #9
i dont have a/c or a heater at all lol
the iac is 4 months old, you can hear it working too.
 
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