Allpar Forums banner
1 - 5 of 5 Posts

·
Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
Joined
·
23,917 Posts
Welcome to Allpar. What refrigerant is in the A/C? I have had compressors drag down and stall engines from over-oiling and compressor seizure. Does the inner A/C clutch pulley hub turn somewhat freely?

Use of OEM O2, MAP, TPS and PCV might be an important consideration here. I have had issues with some aftermarket sensors and valves.

Does this car have an EGR valve? I have had those leak exhaust into the intake at idle, even with the vacuum hose off. The pintle was burnt off the stem causing full EGR all the time.

The TBI fuel injectors were known to have spray pattern issues. Does it drip while idling? It should have a hollow cone shape that can be seen with an advance timing light used as a strobe. Dial it in until the cone is visible.

Timing is checked with the 2-wire coolant sensor disconnected. It will be way retarded if it is left on while checking timing. Disconnecting it will turn on the 'ck eng' (Power Loss) light, but that can be cleared adter the procedure.
While setting timing with an advance timing light, check the cam sprocket timing mark at 0º. The mark should be centered in the belt cover window.

This is OBD1 with the Chrysler diagnostic connector in the engine compartment. It would be interesting to see a health check of the target idle, O2 sensor switching and injector pulsewidth if you have or know someone who has this tool.
 

·
Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
Joined
·
23,917 Posts
Any stored fault codes? These may have had a red 'Power Loss' light instead of a yellow 'ck eng' icon. Does the 'Power Loss' warning lamp come on for a bulb check at start-up?
The key dance allows you to count-pause-count lamp blinks for a 2-digit code. 55 means 'end of test'.
 

·
Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
Joined
·
23,917 Posts
The PCM is supposed to control idle speed. When you first start the car, the idle speed should 'flare' to nearly 1000 rpm beforw settling down to around 750 rpm. Does it have the start-up flare?

The PCM keeps a target idle which it tries to maintain by slightly opening or closing the IAC (idle air control) motor/valve. An IAC is a 'stepper' motor and basically a computer-controlled vacuum leak. It opens and admits air to raise speed and closes to reduce speed. It tries to maintain target idle.
A tug on the steering wheel, A/C compressor engagement or putting it in 'R' or 'D' will drop the idle and the PCM will compensate by opening the IAC enough to maintain target idle.

There is no manual idle speed adjustment. The minimum air screw is adjusted at the factory and should never need adjustment. The screw head is sealed with a plug. If the plug is missing to expose the screw head, someone has likely tampered the adjustment. There is a special tool and procedure for setting minimum air (again, it is not an idle speed adjustment).
The IAC is a 4-wire motor, 2 wires drive the motor in or out and 2 wires feed back to the PCM where the motor position is (in steps).

This car is OBD1. If you can borrow a scan tool with the Chrysler diagnostic cable, it may be easier to diagnose the low idle. The wiring and hoses behind the valve cover were a trouble spot as the heat from the exhaust manifold would cook and harden the plastic and rubber after some years.

 

·
Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
Joined
·
23,917 Posts
You will want the OEM Champion RN12YC Copper Plus for best burn.
 

·
Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
Joined
·
23,917 Posts
The image below is for a RWD transmission, but FWD works the same way. The center contact terminal (#2) grounds to the manual (selector) shaft 'comb' in the P and N positions through the metal nub.
Selecting Reverse allows the nylon switch button to close a switch between the outer 2 contacts (#1 and #3) to send 12v to the rear lamps.
Switch continuities can be tested with a meter.



82196
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top