What does the 1995 to present Toyota® T100® truck, Tacoma®, 4Runner®, Tundra® and the 1987 to 1989 Toyota® MR2® have in common? "They're all made by Toyota®," you say. Well, that's right, but one other thing they all share commonly is that they all are available with factory-installed superchargers.

All manufacturers are currently doing a good job of building fairly dependable vehicles. But you have to admit, Toyota® has been building a great line of vehicles for some time. You can always count on hearing owners' comments like, "It's so dependable, I've driven this car for 150,000 miles with virtually no problems," or "This is the best vehicle I've ever owned." So, when the factory decides to step outside the mainstream and offer something a little extraordinary, it's a safe bet they did their best to make sure the new models uphold their stellar image.

Although Toyota® takes the time to build quality into their vehicles, the true test of any component is extreme, everyday use, during all types of conditions, by all types drivers. This month, we'll discuss diagnosing a squeaking/rattling noise and performing maintenance on one of these supercharged "masterpieces of technology".

First, let's talk about the squeaking/rattling noise problem. Some 1998 Toyota 4Runner®, Tacoma®, T100®, and Tundra® vehicles with 3.4L V6 may exhibit a squeak or rattle noise from the supercharger drive-belt idler pulley.

Pulley Squeak or Rattle
Due to a possible out-of-tolerance condition on the idler pulley shaft, some pulleys may have bearings that spin on the inner shaft and will cause a squeaking or rattling noise. The supercharger may be perfectly fine, and the source of the noise may simply be the idler pulley.

Removing the supercharger drive belt and checking the movement of the pulley on the shaft can verify this condition. The pulley should not slide back and forth on the shaft. If it does, it needs to be replaced.

To replace the pulley:
1. Loosen the drive belt and remove the idler plate assembly. Retain all the hardware.
2. Remove the idler pulley sub-assembly from the idler plate assembly.
3. Replace it with the supplied new idler pulley sub-assembly.
4. Replace the idler plate assembly and all of the hardware.
5. Reinstall and tension the drive belt to 120-ft lbs. for a new belt or 80 ft lbs. for a used belt (any belt used for more than 10 minutes).

That should take care of that annoying little problem. Now, let's talk about the two maintenance tips: replacing the fuel injectors and changing the oil. Both tips concern the 1987 Toyota® MR2® with a 4A-GZE Supercharged engine.

Fuel Injector Replacement Fuel injectors are color coded according to flow rate and matched to the engine at the assembly plant. Note that all four injectors installed on the engine must be of the same color-coding. If replacement of one injector is necessary, replace it with only an injector of the same color-coding as the one originally installed. For example, four yellow-coded injectors cannot be substituted for four black-coded injectors. Individual part numbers for the injectors are as follows: 23209-16060 - 01 = Blue 23209-16060 - 02 = Black 23209-16060 - 03 = Yellow 23209-16060 - 04 = White	The location of the injector color mark is shown in the illustration.
Supercharger Oil Change The next maintenance tip is about checking the oil contained in the supercharger. Special maintenance procedures required for checking or replenishing the oil level of the supercharger assembly installed on the MR2® with a 4A-GZE engine should be followed exactly. The Supercharger oil level should be checked every 30,000 miles (48,000 km) or 36 months and if the oil needs to be topped off or replaced. Be on the safe side and use Toyota® Supercharger Oil, part number 08885-80108. The special procedure is as follows.
1. First, you should check the oil level on the dipstick with the engine cold and the vehicle on level ground. To improve access to the dipstick, follow these steps: Remove the clamp-retaining bolt. Remove the vacuum-switching valve retaining bolt. Do not disconnect the hoses from the vacuum-switching valve. Turn the yellow-headed supercharger oil level dipstick counterclockwise and remove. 2. Wipe the dipstick clean with a rag. 3. Reinsert the dipstick-turn it fully clockwise, or the reading will not be correct.
4. Remove the dipstick again and check the oil level. If it is between the "F" and "L" marks it is okay. If the oil level is below the "L" mark (or not showing on the dipstick), add oil up to the "F" line.
NOTES: 1. Add Toyota® supercharger oil through the dipstick tube with a syringe or equivalent devise. 2. Always recheck the oil level. 3. Avoid overfilling or a low oil level, which could damage the supercharger. And there you have it. One minor problem resolution and two maintenance items that will hopefully make your job easier when confronted with a supercharged Toyota® of one type or another.