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> Idle hunting, Where do I start?
steuspeed
post Mar 16 2021, 07:24 PM
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I'm working on fixing my idle search. All new vacuum lines, plugs and wires. Car starts and runs smooth for about 1-2minutes, then the idle dumps and starts hunting up and down. My ECU knob was turned full clockwise by the PO. I turned it back to the factory setting.

Stock 2.0L 1973 car with Pertronix. Where should I look next?
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BeatNavy
post Mar 17 2021, 05:50 PM
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I think you're running lean. You need to troubleshoot the things that can cause that condition:

1. Low fuel pressure
2. Clogged injectors
3. Incorrect TPS calibration (although it seems like your idle knob IS making a difference)
4. Bad or poorly tuned MPS
5. Missing (or bad) D-Jet component, e.g., as Bleyseng says, ballast resistor.
6. etc. etc.

Try disconnecting the TI (ambient air temp) sensor. That will enrichen things a tad. See what impact that has, if any.

Are you seeing any symptoms outside of idle? Poor power or hesitation, bucking, etc.?

I assume you don't have an O2 sensor / gauge.
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steuspeed   Idle hunting   Mar 16 2021, 07:24 PM
Bleyseng   Do you have the resistor installed?   Mar 16 2021, 11:36 PM
steuspeed   I see a white wire/connector/black wire to cylinde...   Mar 17 2021, 04:59 PM
rjames   Are you sure no vacuum leaks? Does changing the po...   Mar 17 2021, 01:14 AM
steuspeed   Are you sure no vacuum leaks? Does changing the p...   Mar 17 2021, 05:17 PM
wonkipop   not sure i can help as have a 1.8 L jet. but have ...   Mar 17 2021, 01:24 AM
BeatNavy   I think you're running lean. You need to trou...   Mar 17 2021, 05:50 PM
steuspeed   I think you're running lean. You need to tro...   Mar 18 2021, 03:36 PM
914werke   :agree: hunting idle is usually a symptom of lean ...   Mar 17 2021, 06:09 PM
steuspeed   :agree: hunting idle is usually a symptom of lean...   Mar 18 2021, 12:09 AM
mgphoto   Most times it’s the idle screw on the throttle b...   Mar 17 2021, 09:44 PM
steuspeed   Most times it’s the idle screw on the throttle ...   Mar 18 2021, 12:10 AM
cary   Concur with Rob & Rich, too lean.   Mar 17 2021, 11:01 PM
BeatNavy   I wouldn't worry too much about the idle bypas...   Mar 18 2021, 05:18 AM
steuspeed   I wouldn't worry too much about the idle bypa...   Mar 18 2021, 03:38 PM
saigon71   Agreed that you are running lean at idle. Start...   Mar 19 2021, 05:33 AM
JamesM   Agreed that you are running lean at idle. Star...   Mar 19 2021, 08:45 AM
rjames   Agreed that you are running lean at idle. Sta...   Mar 19 2021, 11:39 AM
914_7T3   My ‘73 had the same symptoms and it was indeed t...   Mar 19 2021, 01:28 PM


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