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SC400 a little sluggish/ odd idle


Old 03-07-18, 12:51 PM
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Default SC400 a little sluggish/ odd idle

Picked up a new to me manual swapped SC400, was S/C by previous owner but now it's NA again. Had a ton of vacuum leaks/most of the systems were taken off for the EFI and had a rotted rear subframe. Replaced everything from the blown HG shell I had sitting here. Now it's running and driving 100x better but still doesn't feel as fast as I think it should and has a weird condition we're it will get caught in a high idle loop like warm up enrichment(1100-1200) no matter what temp it's at. if I turn the car off and back on once it's warmed up it will drop down the regular 600 rpm idle some driving will result in it climbing to 800. I was thinking maybe CLT sensor but there isn't a code. All I got was a 27 & 29 (obd1). That's sub o2's? Don't think they affect the afr at all but may be mistaken. Need some expertise
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Old 03-09-18, 08:24 AM
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Most of the time, Sub Oxygen Sensors monitor the Catalyst efficiency, so I doubt that would be your problem. Older SCs tend to have issues with both the VAC meter and Idle Air Control Valve. Also do not forget, that OBD 1 only sets codes for hard faults (IE: the component has 100% failed). So even if said components are sending bad signals to the ECM, it will not set codes for them. Manual inspection and testing will be needed.
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