QuestionQUESTION: 102,000 miles new complete tune up wires, dist cap etc
Runs very smooth until a/c comes on then RPMS start dropping motor wants to shut down
A/c woorks gret cold air compressor , clutch works fine
ANSWER: Hi Fred,
There are several things you might try. First turn the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the odometer window to see if the mileage changes to show any 4-digit numbers preceded by a P. If so let me know what they are. If not, then instead watch the check engine light to see it begin to flash, pause, flash, etc. Count the number of flashes before each pause. Repeat to be sure of an accurate flash count and let me know. These fault codes may give an idea of what is wrong.
The other items are: the compressor may nonetheless be putting too much of a load, but this is not so likely. The engine control module is supposed to ramp up the idle when you request AC. It could be that the Idle air control 'motor' needs to be cleaned (remove from side of throttle body clean the tip and clean the opening into the side air passageway in the throat of the throttle body) and also while you are there clean the throat of the throttle body and both sides of the butterfly valve plate.
The ecm is supposed to instruct the IAC to open and to increase the fuel pulse width, and that might not be happening but only a fault code would tell us that or a readout with a sophisticated code reader would also show if the pulse width changed or not. Cleaning the throttle body/iac motor is the first thing to try, after the code readout.
Let me know how this works out.
Roland
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QUESTION: I did a code read initially when the check engine light came on and got a code #1 & #3 misfire thats when I did a complete tuneup, I forgot to tell you that the Tach and spedomenter milage indicator work intermittenly, the milage indicator does not light up all the time even though the speedometer registers the speed ok
AnswerIf the code for the misfire is gone, then what I suggested to do is the next step. You can erase stale codes by disconnecting the battery. But that does cause a 1684 code you can ignore.
The cluster may be a problem with a 'cold' solder joint between one of the socket pins and the printed circuit board so try removing that and reheating the joints with a solder pencil.
