1994 Toyota Supra Problems
RepairPal has identified the most common problems with the 1994 Toyota Supra based on complaints from actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.
A loss of power on the freeway may due to an internally leaking fuel pulsation dampener. This commonly occurs on higher mileage vehicles.
The 1993-2002 Toyota Supra and Toyota Supra Turbo radiator may crack near the radiator cap. When it cracks, the engine will begin to run warmer than normal, and eventually will overheat. Overheating will also be accompanied by a sweet smell around the front of the vehicle, most noticeable under the hood.
Replacement of the radiator is the only solution, as the crack occurs on plastic.
The upper radiator hose on the 1993-2002 Toyota Supra is known to buckle, and contact the engine fan. When this occurs, the engine will immediately overheat, and hot coolant will pour on the engine causing steam from the engine bay.
The solution is to replace the radiator hose and coolant, and bleed the cooling system.
To prevent this from occurring, the radiator hoses should be changed every 60,000 miles.
The windows on the MKIV Toyota Supra commonly lean in towards the cabin when they are rolled down, and a metal-on-glass rattle is heard with any vibration. As the problem advances, popping may be heard from the door as the window rolls up or down.
This issue is caused by a failing window regulator which no longer holds the window upright, and places undue strain on pads that prevent the window from contacting the metal door frame. After a short time, the pads inside the door wear out, allowing the window to rattle and become scratched.
To correct the rattling and popping noises, the window regulator and pads must be replaced.
The MKIV Toyota Supra and Supra Turbo electric window regulator motors wear out much faster than expected.
This causes the windows to raise and lower very slowly until they eventually stop working. This has been reported on vehicles with less than 50,000 miles.
To fix the issue, the entire window regulator must be replaced.
At higher mileages (125,000+) the Engine Coolant Temperature Sensor may intermittently stop working, especially when the vehicle is fully warmed up. This can cause the engine to stall unexpectedly.
The EGR System tends to get restricted or blocked with carbon after 100,000- 125,000 miles which will cause an emissions test failure for NOX. If the EGR system is equipped with an EGR temperature sensor it will trigger a Check Engine Light for improper EGR flow. The repair is to clean out the EGR passages and the EGR Temperature sensor. Our technicians tell this repair is pretty straight forward and takes about 1-1.5 hours. It is also wise to verify the EGR system components i.e. the Transducer, EGR Valve and VSV Solenoid at this time.
The AC Expansion Valve may develop a very slow leak or allow too much refrigerant flow which reduces cooling. Our technicians tell us that Toyota makes an updated expansion valve to resolve these problems if and when they occur.
The Throttle Position Sensor can get out of adjustment due to wear in the throttle body or due to carbon build up. This will cause the idle timing to advance more than 30 degrees which will cause very high HC and NOx emissions. Conversely, the Throttle Position Sensors can wear out and not properly advance the timing which causes a lack of power and poor fuel economy.
A rough idle and even an emissions inspection failure for high HC and CO can be caused by improperly adjusted valves. Also, exhaust valves may become to tight which can lead to valve failures. Our technicians tell us that regular valve adjustment inspections are a must.
If the vehicle will not crank over, the most common problem is the starter, which tend to fail at about 100,00-125,000 miles. Sometimes it is only the starter solenoid contacts, but often the complete starter (including solenoid) needs to be replaced.