More Power Through Electronics Q:I own an '03 GMC Sierra 5.3-liter V-8 regular cab shortbed weighing around 4100 pounds. It has two-wheel drive with 3.73:1 gears, Flowmasters, and I've had it lowered. I read the part about Superchips in your July/August 2003 issue (pg. 53). I am now considering buying a chip from Superchips called the MAX Micro Tuner, because I want to get rid of the top-speed governor and get more power. The Web site for Superchips says it would be easy to install, could take out the top-speed governor, and provide a few extra horsepower. Could you tell me about the installation of the chip? What if something goes wrong while installing it, etc.?
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A:First off, the Max MicroTuner from Superchips is not a chip. It's a program tool that will modify the manufacturer's PCM (Powertrain Control Module) factory settings on fuel delivery, ignition timing, etc. It's a simple procedure if you follow the directions after plugging into the vehicle's diagnostic connector. If there is a problem, give tech support a call at 407/547-0130. I wouldn't worry about messing up since you'll always have the option of setting the PCM back to its original calibration. I looked into the numbers on your particular GMC truck, and Superchips tells us you should get an increase of about 15 horsepower and 26 pound-feet of torque at the rear wheels, and the rev and speed limitations will go up about 200-400 rpm and 30-40 mph. You can also view any trouble codes stored in the computer's memory if the Check Engine indicator should ever light up on the instrument panel. The MSR is currently at $419, and you may gain a bit more in power due to your previous performance modifications. Remember to use premium fuel when all is said and done.
Servicing the 4WD Light Q:I drive a '99 Silverado Z71. The display on my truck says, "Service 4WD." It tends to stall when you switch gears. I took it to the dealership, but they couldn't find anything wrong. The message display box didn't display. They reset it and charged me $70! The next day it came on again. I complained to them about it. This time the message was on while they were checking it with a scanner. According to the scanner everything is running normally. They don't know what it is. Right now I am checking it myself.
A:Your Silverado is equipped with the NVG 236/246 two-speed transfer case. When the "Service AWD/4WD" indicator lights up, there's typically a trouble code set in the Automatic 4WD Transfer Case control module, directing the technician to the cause of the failure. It'll require the appropriate scan tool to read and/or erase the code(s). However, once the condition is no longer present, the light will go out, and the trouble code will then be stored in a "history" category. Once the ignition has been cycled on and off 100 times, the code will then be cleared altogether. Regardless, if the service indicator was consistently on the second time you brought the truck in to the dealer, there's no reason they shouldn't have been able to diagnose the problem. There's always the possibility of a failure activating the light without storing a trouble code in memory, but the light being on solid should still be an easy path to follow by a qualified technician. If it's an intermittent problem and the indicator is off with no trouble codes stored, then diagnosis is that much more difficult and may require considerable time and effort to fix. Give the folks at the Chevy dealer another shot, and leave the truck with them for as long as it takes to get it right. The stalling should be unrelated. Maybe we'll get into that next time.
Eating Too Much Oil Q:In 2002, I bought a new Chevrolet Silverado extended-cab 1/2-ton pickup with the 5.3-liter engine. I thought I was getting a fairly good deal since I bought the same type vehicle in 1993 (350 engine), and it has 190,000 miles on it and is still going. My 2002 has 11,000 miles on it, and it's using a considerable amount of oil between oil changes. I called the dealership to have it checked, and they informed me that Chevrolet considers it normal if the engine uses up to one quart of oil every 1000 miles; they will do nothing unless it exceeds this amount. I have owned many new vehicles in my life; I have never heard of anything this ridiculous.
A:Chevy trucks were completely redesigned in 1999, and the 5.3-liter V-8 is an entirely different engine as compared with the old faithful small-block 350 (5.7-liter). However, the excessive oil-consumption parameters documented by General Motors remain the same. The manufacturer considers anything more than "one quart every 2000 miles" excessive and warrants concern. The first thing to do is inform the dealer that told you one quart every 1000 miles to get their numbers straight. Then have them perform an oil-consumption test to determine an accurate volume of oil being used. This will involve marking the dipstick and driving the vehicle for 2K miles, and then measuring the exact amount of oil it takes to bring the level back to the mark. This needs be done at a common temperature, the vehicle level, using the correct oil grade, and enough time allowed for the oil to settle down to the oil pan. If the engine has burned more than a quart then it's time to perform mechanical diagnosis starting with the correct operation of the PCV (positive crankcase ventilation) system and working your way down to an inspection for damaged piston rings. Keep in mind that every engine does normally consume oil and the amount will vary depending on driving conditions. Also, a brand-new engine will typically burn more oil until the piston rings have seated properly in the cylinder bore.
Disappearing Display Info Q:I recently purchased a 1994 Jeep Grand Cherokee SUV and the diagnostic computer seems completely bonkers. It's telling me that the rear taillights, the washer sensor, and the coolant are bad. I know the taillights work, so I assume this is just the result of faulty electronics. The radio and CD player (Infinity) work fine, but the display is blank, meaning you can't see what station or track you're on. Is there anything I can do?
A:Whenever you're working with several electronic component failures at the same time, you have to start by searching for a common link. The instrument panel lights, taillights, and fluid-level warning indicators on your particular Grand Cherokee all come together at the VIC (vehicle information center) located in the lower part of the center console. Of course, when working with older vehicles there's always the possibility of multiple problems accumulating as time and miles wear on, but chances are they won't hit you all at once. Get a test-light and/or someone who knows how to use one, and find the fuse box located under the dash. Then find the 15-amp fuse labeled #21 that powers the VIC module and check for voltage on either side. If it's burnt then replace it to see how many items return to normal operation. Keep in mind that a short has caused the fuse to pop and it may happen again. If the fuse is good then get your Jeep to a professional before replacing any parts.
Biodiesel and Your Warranty Q:I've heard that biodiesel is a good thing for your engine. They say it helps to lubricate it while the fuel burns, is better for the environment, and can get rid of some emissions. Is this true? If it is, I'd like to start running it in my 2001 7.3-liter.
A:I haven't seen any evidence of engine benefits, but I was able to get a copy of Ford Motor Company's stance on biodiesel fuel in Power Stroke engines. Biodiesel fuel contains components of fatty acids usually derived from soy or rapeseed with methanol and other catalysts in the mixture. The Environmental Protection Agency has determined through studies that a blend of 20-percent biodiesel and 80-percent petroleum-based diesel fuel does significantly reduce some harmful emissions. However, Ford Motor Company and most diesel-engine manufacturers will not support the use of more than five-percent biodiesel fuel in the mixture, and this small amount will have limited effects on emissions output. There are a number of possible harmful side effects that require further research. An excessive rise in fuel viscosity in cold temperatures, risk of microbial contamination, higher engine-deposit formations, and seal breakdowns are just a few. Therefore the use of a higher concentration is at the sole discretion of the owner and may void a warranty engine repair if the nonrecommended fuel mixture is determined the cause of the failure. I suggest sticking with petroleum diesel at this point in time if you're concerned about premature wear of your truck's engine and fuel-delivery components. There may be a reduced risk with future studies and refinement, and manufacturers are always working on emissions reduction through every means at their disposal.
Looking for Vibration Clues Q:I drive a 1997 F-150 5.7-liter four-wheel-drive pickup and am now on my fourth radiator. It seems to develop a crack/leak along the right (passenger-side) bottom corner on a regular basis. The dealer(s) have not been able to give me a reason for this except for undue torsion twist caused by heavy off-road use. I don't go off-road that often and never seriously when I do. Could my frame be twisted? No accidents, bought used at 43,000 miles, and no paper trail of damage. Any suggestions?
A:I haven't heard of this one being a common problem or factory defect on the F-150. If it happens again, I'd find a technician to carefully inspect everything surrounding the radiator during disassembly and removal. To avoid damage from chassis flex and vibration transmitted through the radiator support, most radiators are mounted with the use of rubber insulators. Possible causes of the problem: anything and everything that could be making contact with the radiator in the area of the crack. It may look far-off with the truck parked, but movement of the engine under high torque situations may cause parts to move significantly, especially when a broken motor mount comes into play. Also, carefully inspect the radiator insulators and attaching brackets position and condition. There may have been a mystery crash in the past that has malformed the factory position of the support where the radiator mounts. This may cause the insulators to not align properly and force the radiator to make metal contact, or the clearance is insufficient and tightening down on the insulators has caused excessive external stress. You should also inspect the radiator support for any signs of cracks or broken welds.
