QuestionI own a 3000GT 1994 VR-4 (6speed, manual, all stock). A couple months ago my ABS light came on when I started my car in the morning. After arriving at work and turning the car off, I heard a noise coming from the engine compartment on the right side (POV: sitting in drivers seat) which I can only describe as an electric motor constantly running. Since the car was already off, the only thing I could think of was to unplug the battery. 8 hours later when I plugged it back in the ABS light did not come on, and when I got home the electric motor noise had stopped.
A week or two afterwards, the tach started reading sub-1000rpm when coming to a stop. The RPMs were falling so fast that turning left or right out of gear would nearly stall the engine (the warning lights would flash when the rpms got too low) However, sometimes the rpms would fall to 500rpm and no lower. A couple times while parking the engine would stall completely and I would loose power steering. However, when I gassed the car at this point the car ran fine, as long as the rpms were above 1000. (which is the min rpm anyway) The brakes also squeak when I'm about to stop and pressing fairly hard where as almost no pressure makes no squeaking.
The ABS light has come on about 4 times afterward and each time the motor noise is heard after turning the car off. One time I just left it overnight and in the morning the noise was still going.
My question is this: Do you think these two symptoms are related? (ABS Light/motor noise & low RPM/stalling) What do you think is the culprit? What should I tell the mechanic to test to ensure the car is checked out properly?
I read somewhere that the brake booster might malfunction and cause symptoms like this, but I also read that the steppa motor(?) needs to be replaced.
I also read that the oxygen sensors should be replaced or the intake system cleaned.
I have tried cleaning the butterfly valve with air intake system cleaner and that did nothing but make my car smell awful when the rpms were low.
I have taken the car to the dealer twice and neither time the ABS light went on for them, and I don't think they even drove the car around to check the stalling problem as the milage hadnt changed.
Thanks in advance for any knowledge you may have to help solve my problem!
-Tom
AnswerTom,
I don't think your two problems are related.
The ABS llight comes on for a couple reason. One, if your brake fluid is low, or there's excess air in the brake lines, the light will come on. Your ABS system may be having a problem, or may be warning you that your brake pads are starting to wear down too far. The speaking noise may be another indication of that as well. The VR-4s are pretty complicated machines, but the braking system is pretty common compared to other cars. Most any mechanic would be able to inspect your brake system for these problems. I don't think a bad brake booster or master cylinder would be causing this. If they were the problem, you'd be able to push the brake pedal all the way down with almost no resistance.
Your low idle can also be caused by several factors. I would recommend having your throttle posistion sensor (TPS) and idle speed control (ISC) motor inspected. Both of these devices are responsible for controlling your car's idle speed. Get your PCV valve replaced too. The PCV valve is only a few bucks, and can be changed in about 10 minutes. Something in your ignition system might be causing this. Have your alternator, spark plugs, plug wires, and ignition coil checked. Ignition coils rarely go bad, but it can't hurt to check. New plugs and plug wires are good to change every 30,000 miles. Alternators in Mitsubishis usually need replacing every 7-10 years. Your timing belts should also be inspected. If your timing is off due to a belt that has slipped a couple teeth can cause this problem. If your timing belts have not been changed within the past 60,000 miles, it should be changed as preventative maintenance.
A final thing that should be checked is your car's computer. Read this article for further information:
http://90gsx.com/eclipse/cap/caps.htm
If your ECU is malfunctioning, you can have all sorts of strange and random problems.
Good luck!
