Cars

Why is my minivan stalling out?

John Paul, AAA Northeast's Car Doctor, answers a question from a reader having trouble with a 12-year-old van.

The 2010 Chrysler Town & Country Walter P. Chrysler Signature Series Chrysler

Q. I have a 2010 Chrysler Town & Country with only 69,000 miles. It stalls out when I drive short distances. When I restart it usually runs fine, but sometimes stalls again. Can you tell me why this happens?

A. For an engine to run it requires fuel, spark, and proper engine timing. There are several possible issues that could cause the stalling problem. One common issue that triggered a recall was a faulty ignition switch. I would also look for a sticking EGR valve and clean the throttle body. At 12 years old, even with the low miles, the fuel pump may also be acting up. When checking the fuel pump, both fuel pressure and fuel volume should be verified.  

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Q. Now that the snow season is over, I have a full tank of 2 stroke mix gas- 50:1 +Stabil for the snow blower, plus three gallons of mix of the same fuel in the shed. Can I put a little bit in the cars each time I fill up? Or just let it sit until next winter? Will the car blow blue smoke if I do this? 

A. Adding a quart or so of the gasoline is an effective way to use it up. With only 2.5 ounces of oil mixed with one gallon of gasoline you will not see any smoke. There will not be any harm to the engine or the environment. 

Q. I own a 1999 Mercury Grand Marquis. It runs well and has 155,000 miles. Recently on the highway the cruise control did not kick in. Could this be a fuse or a computer issue, and can it be fixed without too much work? 

A. There are two fuses that need to be checked. One is the servo, which is the speed sensor, as well as the brake light switch. A common issue is the brake light switch goes out of adjustment and causes the cruise control to cancel. 

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Q. I have a procedure question for you. I try to do minor repairs on my 1986 Dodge D150 whenever I can. When required to disconnect the battery I always removed the positive terminal first. However, my shop manual says to remove the negative terminal. I am going to replace the starter soon. Which procedure is best and why? 

A. Disconnecting the negative cable first is the preferred and safest method. If you disconnected the positive cable first and the wrench you are using touched metal (circuit to ground) there would be sparks, heat, and even a possible battery explosion. Removing the negative cable first eliminates that possible hazard. 

Q. Porsche mechanics recommend changing brake fluid once a year for cars used on track or autocross due to the extreme braking requirements during events. High heat from braking apparently breaks down brake fluid. I own a Boxster that is used for getting ice cream, not for racing, but I want to be safe. 

A. If you have ever watched competition racing, the brake rotors under extreme conditions will glow red hot. The extremely high temperature will cause brake fluid to break down and moisture to boil, causing extreme brake fade. In day-to-day driving replacing brake fluid every 30,000 miles is recommended by the automotive engineering group at AAA. If your driving is very limited, replacing the fluid every five years is money well spent. 

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Q. My 2015 Chevy Silverado has an issue with the theft deterrent system that keeps the truck from starting. Occasionally the info screen displays a low battery warning. The battery is new, and the dealer says they cannot pull any codes from the computer. Is there an unposted fix? 

A. Since you are getting the low battery warning I would start with testing not just the battery but the connections to the battery. Performing a voltage drop test is necessary – visually looking at the cables is not sufficient. I have seen several cases where corrosion hidden under the cables causes enough of a drop in voltage to cause some of these issues. When the key (try a spare key) is inserted into the ignition, the transponder-embedded key is energized by the exciter coil that surrounds the ignition switch. This action sends a signal to the body control module to allow the engine to start. Unfortunately, there is no simple fix, and it will take a technician measuring voltages across several circuits to find the problem. 

John Paul is AAA Northeast’s Car Doctor. He has over 40 years of experience in the automotive business and is an ASE-certified master technician. E-mail your car question to jpaul[email protected]. Listen to Car Doctor on the radio at 10 a.m. every Saturday on 104.9 FM or online at northshore1049.com.

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