Q--When I purchased my vehicle in 1996, the manufacturer recommended 89 octane gasoline. But, I was advised that the car would run fine on 87 octane as the computer would make the necessary adjustments. I have had no problems with the 87 octane.
However, now that the differential in cost (87 vs. 89) is less than three percent (even though the price of gas has gone up considerably) might there be sufficient improvement in gas mileage to justify the cost difference?
A--That is a good question and one I cannot answer since you did not give me any information about your current gas mileage or the gas mileage you used to get when using the 89-octane stuff. The solution is buried in the sentence above. Note your fuel economy using regular (87) then do the same after-switching to mid-grade (89). To be fair, run at least a couple tanks of the more expensive stuff. Is the difference greater than three percent?
Clean injectors
Q--I am attaching an article from the Milwaukee Journal on the issue of fuel. I had to spend $1200 to replace my fuel injectors after my mechanic was unable to clean them. How do I obtain a copy of the service bulletin issued to GM dealers June 29, which says in bold print, "It is not necessary or acceptable to replace injectors that have not been tested and cleaned using the procedure outlined in the attached bulletin (or to replace entire sets of injectors if only a few are found to be restricted or leaking.)" Also, what is the procedure for filing a complaint with GM?
A--You can get extracts of service bulletins from the National Highway Traffic Safety Administration's Web site by entering the year, make, model of your car. From there, you will have the TSB number, which you can take to the dealer and ask him for a copy. Most of them will do that for you as a favor. The other alternative is to pay for a service that provides all of the bulletins for your car. The most popular is AllData. A subscription is about $25 per year per car.
The procedure for filing complaints can be found in your owner's manual. Remember that you also have arbitration and legal recourse as options.
Hot VW action
Q--I own a 2001 VW Jetta with just over 80,000 miles that my college-age kids use when they are at home. During a one-month period the car was serviced for five separate emissions control problems, including the mass air flow sensor, a vacuum leak, two oxygen sensors, the speed sensor, and finally the catalytic converter.
I was told by VW that this could not be a computer or engine monitoring malfunction but was actually a logical progression of failures. The first problem occurred at the same time as a water pump and thermostat failure and the car overheated (I don't know which part failed first). Now the "check engine" light is on again. Is it possible for this series of failures to occur naturally, or is it possible that the computer or the initial overheating episode is the root of the problem? My trusted local mechanic is at a loss and VW is no help.
A--The overheating problem was most likely independent of anything else and it is not unusual to replace the thermostat when replacing a water pump as the 'stat could have been damaged by the overheating.
The MAF (mass airflow sensor), vacuum leak, oxygen sensors and catalytic converter could be related. If the MAF failed, the computer is not sure how much fuel to add to the incoming air so it defaults to a specific air/fuel map (program) to keep the car running. Ditto if there is a vacuum leak downstream of the MAF, allowing unmetered air into the engine, making it run lean.
If it is too lean, a lean miss develops, causing unburned fuel to continue downstream to the catalytic converter where excess fuel causes the converter to overheat and fail. Oxygen sensors are located between the engine and cat so a poorly running engine may cause them to become carbon-coated, causing them to fail. But, I don't know this for sure. See where I am going? As for the current warning light, I haven't a guess.
Pink or green?
Q--Do I need to keep the pink coolant my Chevy came with? Can I switch to green stuff that I have been using for years?
A--You need not stay with the orange stuff (Dex-Cool) so feel free to install the green stuff as long as you thoroughly flush the cooling system first. Also, the green stuff should be drained and replaced every two years - instead of the extended schedule for orange stuff. Unless, that is, the green stuff you choose is one of the new long-life coolants with organic acid technology (OAT) which you can leave it longer. Confused? You are not alone. My best advice: Thoroughly clean the cooling system then follow the coolant manufacturer's guidelines.
False alarms
Q--I have a 1997 Grand Cherokee Laredo that intermittently alerts me that the coolant sensor is bad, but only in warm weather. This started to occur last summer, and I immediately replaced the coolant sensor, which had no effect on the problem.
I've taken the car to the Jeep dealer, but since it didn't happen while the car was in the shop, they weren't able to find the problem, but still charged me for the diagnosis. The warning stayed off all winter, but now as the weather gets warm again, it's starting to return. Any ideas what could be causing the problem? I replaced the coolant about two years ago, the sensor is new, and the coolant level is fine
A--If the coolant sensor is bad, or reporting itself as bad, it could affect the way the computer runs the engine so this must be addressed. I would scan for stored trouble codes first. Next, I would examine the live data stream from the computer. Then I would shoot the coolant temp sensor using an infrared thermometer to find the true temperature.
If everything checks out okay, I would begin looking for a wiring problem between the sensor and computer. It takes methodical detective work.
Flashing updates
Q--You have stated that there are often bulletins regarding reprogramming the computer and that it is free.
I assume you are referring to the EPA's 8/80 emissions warranty covering major components. While the ECM is listed as a covered component, the actual text of the federal regulation does not mention software updates to the ECM.
The reason why I ask is because my local Nissan dealer just changed me $105 for a flash update of the ECM. Do you have any documentation that positively indicates that the software updates to the ECM are covered under the EPA's 8/80 emissions warranty? I would love to get my $105 back.
A-There are actually two federally (EPA) mandated emissions warranties: The "performance warranty" and the "design and defect" warranty. Since you live in a non-attainment area (where you have to take your car in for an emissions inspection), the performance warranty covers adjustments for two years/24,000 miles. Emissions-related hardware is covered for eight years/80,000 miles. In other words, the computer is covered for 8/80, but the programming is covered 2/24. I regret if I misled you.
In the EPA's own words: "If you believe the manufacturer has not honored a valid claim and your vehicle has not exceeded the time and mileage limitations, you should contact an authorized warranty representative and follow the procedures outlined in your owner's manual or warranty booklet. If the authorized dealer denies your warranty claim, contact the manufacturer's regional or zone office for further assistance. If you are still not satisfied, follow the appeals procedure outlined in your manual or warranty booklet.
"Of course, you are entitled to pursue any independent legal actions you consider appropriate to obtain coverage under the emissions warranties. In addition, the Environmental Protection Agency (EPA) is authorized to investigate the failure of manufacturers to comply with the terms of these warranties. If you have followed the manufacturer's procedures (including those for appeals) for making a warranty claim as set out in your owner's manual or warranty booklet, have received a written denial and you are not satisfied with the manufacturer's determination, you may submit a letter to EPA at the following address. It should provide details of the situation including the basis for the claim, a copy of the written denial, copies of your letters to the manufacturers, and copies of any receipts for emission control parts and repairs you have paid for."
U.S. Environmental Protection Agency
Vehicle Programs & Compliance Division (6405J)
Attn: Warranty Complaints
401 M Street, SW
Washington, DC20460
Turn me on
Q---I own a 1990 Camry and sometimes when the key is turned on to start the car nothing at all happens. Everything is dead. After playing with the key back and forth and in and out then the engine will get electric power and start normally. Would you know what needs replaced? The ignition key tumbler or a switch somewhere?
A--The ignition switch is not just somewhere, but is attached to the ignition lock. If the lock is otherwise working, I would suspect a problem with the switch.
Due to the large volume, Bob Weber is unable to answer most questions sent to The Car Connection each month. Some may be answered directly, where possible, and others will be included in future columns if the topic is deemed interesting. Be sure to include your real name and full address (city, state, province, country, etc.) when sending your questions.
Weber, a self-proclaimed swell guy, is an ASE-Certified Master Automobile Technician, freelance writer and former editor of Super Automotive Service magazine. His column, "Motormouth," appears weekly in the Chicago Tribune. He enjoys good tequila, good cigars, and good times. A chemistry school dropout, he still concocts compounds in the kitchen and makes a mean pot of chili. He and his wife live near the Blue Ridge Mountains of Virginia.
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