Hi - I've got a 74 2.0L with stock EFI and it's developed a lean cold idle condition that I've been trying to diagnose. I've procured a backup AAR to try out as mine "seems" to work but I need to test it further. My other thought is the CHT sensor is bad...in taking a reading at the plug jack, I'm getting a jumpy reading of anywhere between 1.5 and 7 ohms. This is at ambient temp of about 85 F in my garage. I have not taken a warm temp yet to see how it goes. I'm wondering if there is a short or bad spot in the wires somewhere that is causing the fluctuation or if this is a normal scenario?
Basically, the car has a low idle at cold start and sometimes tries to die in the process. I also can't adjust the idle with the air bleed screw and ECU mix has not much effect. Could a fluctuation in the CHT cause an issue such as this or should I look elsewhere?
All vacuum lines are new, including intake boots. I've also replaced the throttle body gasket and intake gaskets. Decel valve has been unhooked/hooked up with discernable difference. I have not tested vacuum on MPS but doesn't this typically cause a richness problem? TPS has not been touched but would that cause an issue?
I know it could cause the cold idle problem but what about the lack of idle adjustment?
It's possible the AAR is not functioning correctly and that's on the list to unhook and test for power, etc. I did check for suction at cold idle and it was sucking.... not sure about after warmup. I have not looked at the oil filler gasket yet or the PCV valve.
I've been spending a lot of time on B. Anders site looking at possible causes, etc.
Am I missing anything in this equation? I'm trying to not get frustrated and give up and when I do get too annoyed I just take a break. Let me know what you all think.