Idle hunting, Where do I start? |
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Idle hunting, Where do I start? |
steuspeed |
Mar 16 2021, 07:24 PM
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#1
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Senior Member Group: Members Posts: 1,008 Joined: 12-July 11 From: Portland, Oregon Member No.: 13,308 Region Association: Pacific Northwest |
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? |
BeatNavy |
Mar 17 2021, 05:50 PM
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#2
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Certified Professional Scapegoat Group: Members Posts: 2,944 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
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. |
steuspeed |
Mar 18 2021, 03:36 PM
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#3
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Senior Member Group: Members Posts: 1,008 Joined: 12-July 11 From: Portland, Oregon Member No.: 13,308 Region Association: Pacific Northwest |
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. I checked in my 74 car for a resistor. None in that car either. I swapped the MPS and no change. I disconnected the air temp sensor. No change either. The car runs great. Lots of power. No hesitation or bucking. No O2 sensor. Hands free key starts. Idles nice for about 1-2 minutes before going into oscillation. |
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