Jim Grant's Tech Tips
‘91 Plymouth Acclaim, Steering Wheel Vibrating
Q: I own a ’91 Plymouth Acclaim with 60k miles on it. My problem is that the steering wheel vibrates a lot when I start it and it also when the A/C or defroster is being used. It quits on me when started in the morning and I have to start it a couple or three times and give it some gas. I’ve had a complete tune-up on it. The garage tells me there is nothing else that can be done to eliminate this problem. Is this true?
A: From your description, I’d say it’s possible that the idle air control motor is not working or the minimum idle speed is incorrectly set. Your vehicle, alongwith most Chrysler vehicles, has a computer system that has bi-directional featuresthat works well with good quality computer scan tools. What does this mean foryour vehicle? A properly trained technician with the right computer scan toolcan take control over the vehicle’s computer. This allows the technician toperform function tests on computer-controlled components. This takes us backto your complaint. If a vehicle starts and stalls when cold and seems to needthe gas pedal stepped on to keep running indicates that the cold idle speed isincorrect (too low). When starting any of today’s computerized vehicles you willnotice that the idle speed jumps up and then is slowly lowered. It is to preventstalling when cold and quicken the warm-up to operating temperature. The computeralso uses this idle control feature to handle additional loads, which slows downthe engine’s idle speed. Additional loads are things like your A/C compressorwhich happens to also turn on when the defroster is turn on. The computer respondsto these loads by raising the idle speed. I suggest having a technician thatknows their way around with a computer scan tool to perform a function test ofthe idle air control system and be sure the base settings are correct. Tune-upson today’s vehicles are mainly maintenance/replacement of parts. You need atechnician to diagnose your complaint that a tune-up is not going to fix.