12 Jul

Q & A #64 With The Auto Specialist

Author: Car Parts Guy  |  Category: Autos and Cars, Car Q and A

Q & A #64 With The Auto Specialist

Thanks for joining me for the latest installment of the Auto Specialist. If this is your first time visiting, I’d like to encourage you to take a peek through our archives. Over the past year, we’ve put together an impressive library of automotive Q&A that sheds light on an assortment of car problems. From failing alternators and transmissions to fuel pumps and catalytic converters, we’ve covered it. If you’re experiencing trouble with your vehicle, you’ll likely find the problem has been diagnosed in a past installment.

Today, we’re going to take a look at a misfire that Jason is experiencing with his Accord. We’ll also help Cameron figure out why he’s unable to start his Continental. Lastly, we’ll help Saul with a question he has about his Infiniti QX4′s rough idle. It’s a full docket, so let’s get started.

Question: I have a 2000 Honda Accord with 137,000 miles on it. Over the last week, I’ve been getting a random misfire while driving. It happens both on city streets and at high speeds while I’m on the freeway. Here’s the thing: I’ve done a lot of troubleshooting. I’ve replaced the spark plugs and plug wires, done a compression test, and even checked the manifold absolute pressure sensor. I’ve also gone through the ignition system and looked for trouble codes (I have an OBD-II scanner). Everything seems to check out fine. Can you give me any hints about what may be causing the misfire? Thanks.

Answer: Thanks for sending in your question, Jason. It sounds like you’ve done a good job troubleshooting. Given that everything you mentioned is checking out, I’d say the problem might be with one of your fuel injectors. Occasionally, the injectors will short out and stay open, allowing fuel to flood the cylinder. If that’s the case, replace the injector and the misfire should disappear.

Question: I’m driving a 1999 Lincoln Continental. I replaced the engine about four years ago and the mileage on the new assembly is at 65,000. I’m having trouble starting it. I tested the battery and it seems fine. It’s putting out plenty of voltage. Any idea what might be the problem?

Answer: Thanks for your question, Cameron. There are a lot of factors that might cause a no-start situation. It could be something in the ignition system (for example, the switch, starter solenoid, starter motor, etc.). It may also be a problem in the fuel line.

Here’s what I recommend: first, pull the trouble codes from your powertrain control module (you’ll need access to a scanner). Second, check to make sure the timing belt is fine. Third, test the pressure in your fuel line to verify your engine is receiving sufficient fuel. Last, test your spark plugs. Most no-start cases can be traced back to those items.

Question: I bought a 2002 Infiniti QX4 a few years ago. It has a little under 94,000 miles. Starting a few months ago, the car began to idle roughly and hesitate when I tried to accelerate. It didn’t happen very often at first, but it happens a lot more frequently now. The technician at my dealership tried to get me to agree to a long list of repairs. But I have a feeling that’s unnecessary. What do you suggest I do?

Answer: Thank you for writing in, Saul. When it comes to engine problems, the best place to start troubleshooting is at the powertrain control module. Invest in an OBD-II code reader (you should be able to buy one online for under $40), and use it to pull trouble codes. I’m surprised the tech at your dealership failed to do this. The codes are a bit vague, but you can find their meanings online. That will point you in the right direction.

That’s it for today’s installment. Thanks again to Jason, Cameron, and Saul for giving us an opportunity to help diagnose their automotive problems. We’ll be back next time with another group of questions, so be sure to join us. Until then, drive safely.

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14 Jun

Q & A #62 With The Auto Specialist

Author: Car Parts Guy  |  Category: Autos and Cars, Car Q and A

Q & A #62 With The Auto Specialist

Thanks for joining me for the latest installment of the Auto Specialist. A recent article in the Wall Street Journal reports that early optimism in new car sales this year has faded dramatically. It goes on to report that much of the surge in early-year sales was attributable to car rental agencies and other corporate accounts, as opposed to consumers. As it turns out, consumers have largely abandoned the dealerships as the economy continues to look increasingly uncertain.

If these people are not buying new cars, I’m assuming they’re keeping their current ones on the road. That’s a good idea. It usually costs much less to install a new engine, heater core, or cylinder head than to buy a brand new vehicle.

Today, we’re going to help Daniel figure out what’s causing the “rotten egg” smell in the cabin of his Montero. We’ll also answer Janine’s question about her Neon’s battery. Lastly, we’ll help Patrick figure out why his I30 is idling roughly.

We have a full agenda today, so let’s get started.

Question: I bought a 2001 Mitsubishi Montero a few years back. It currently has 126,000 miles on it. Everything is fine when I’m driving on city streets, but when I get on the freeway, I smell a rotten egg odor. It only seems to happen at high speeds. When I get back onto the city streets, the odor goes away. A friend of mine thought it might be the catalytic converter (it sounds expensive!). Does that seem plausible to you?

Answer: Thanks for your question, Daniel. From what you have described, the air-fuel mixture in one or more of your cylinders is too rich. That is what is producing the odor. If the blend is too rich, your engine’s combustion process will generate more emissions, which will clog your catalytic converter. Whether or not your cat converter is currently failing is a mystery, but I’d definitely have a mechanic figure out why the air-fuel blend is rich. Address that problem first.

Question: I drive a 2004 Dodge Neon with 75,552 miles. Here’s my problem: my car eats batteries. It goes through them much more quickly than it should. Over the last eighteen months, I’ve had to replace the battery three times. My latest one has already run down. Batteries aren’t as expensive as replacing a fuel pump, but the cost is getting up there. What is going on with my car that causes it to drain batteries like this?

Answer: Thanks for writing in, Janine. At this point, I think it’s clear that either something in the charging system is malfunctioning and causing a drain, or your alternator is faulty. One way to check the charging system is to start your engine and turn on your headlights. Press down on the accelerator and watch the lights. If there’s no change, the system is likely fine. If the lights dim, the alternator is probably failing. I encourage you to find the underlying problem before replacing your battery again. Otherwise, you’ll simply run the new one down.

Question: I have a 2000 Infiniti I30 with the odometer at a little over 117,000 miles. Lately, it has started to idle roughly. When I’m driving, however, it seems fine (though it has missed a few times). I took the car into the dealer so one of the technicians could look for trouble codes. The mechanic on duty said the problem is in one particular cylinder. Any idea what might be causing the problem?

Answer: Thanks for sending in your question, Patrick. Unfortunately, there are a lot of things that can cause a rough idle and sporadic misfire. If I were you, I’d replace some of the easier parts, such as the spark plugs and wires, and fuel filter. You may also want to test the oxygen sensors to make sure they’re working properly. Also, assuming you know which cylinder is affected, compression test it. If these things check out, take a look at the fuel injector that supplies the cylinder. Hope that gives you a place to start.

That’s it for today’s installment. I’d like to extend my thanks again to Daniel, Janine, and Patrick for letting us help with their automotive problems. Be sure to come back next time when we’ll have a new batch to diagnose. Until then, drive safely.

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07 Jun

Q & A #61 With The Auto Specialist

Author: Car Parts Guy  |  Category: Autos and Cars, Car Q and A

Q & A #61 With The Auto Specialist

Welcome back to the Auto Specialist. Recently, I was reviewing some of the automotive industry’s latest sales numbers. It looks like the Big 3 (i.e. Ford, GM, and Chrysler) are making enormous strides to regain market share. In May 2010, all three automakers experienced double-digit sales growth over May 2009. It’s a little early to tell whether this is a long-term sales trend or a short-term blip. One thing is clear, though: in light of Toyota’s recent recall-related woes, the Big 3 are moving forward aggressively to attract customers.

In today’s segment, we’re going to take a look at a fuel pump problem in Irv’s GMC Sierra. We’re also going to help Jennifer with a question on oil changes. Lastly, we’ll help Andy figure out whether he should follow his mechanic’s advice and get a new engine for his Ford Escape. That’s a full agenda, so let’s jump right in.

Question: I’m driving a 2002 GMC Sierra with 106,000 miles. It has been fine ever since I bought it used in 2004. A real nice truck. Lately, however, I’ve been having a problem with my fuel injectors. They’re not getting enough fuel for the engine. I’ve cleaned the fuel injection system and removed the injectors to check them for sediment. They’re clean.

Usually, I can start the truck just fine, but it stalls out within fifteen or twenty minutes. It doesn’t happen all the time, but it happens enough that it has become very frustrating. Any idea why my fuel injectors aren’t working?

Answer: Thanks for writing in, Irv. From what you’ve described, I’m thinking the injectors are working fine. The problem may be with the fuel pump. It might not be producing a sufficient amount of pressure within the lines. That would explain why fuel is not getting to your engine despite the injectors being clean. I suggest having the pump replaced.

Question: I have a 2005 Infiniti M45. The mechanics at the dealership keep recommending that I have my oil changed every 3,000 miles. They tell me that waiting could damage the engine. To be honest, it’s not the cost of the service that prevents me from having the oil changed more often than I currently do. It’s the inconvenience of driving to the dealership and waiting for them to finish. So, do I need to have the oil changed every 3,000 miles to protect my engine?

Answer: Thanks for your question, Jennifer. Given the age of your engine, I’d say it’s completely unnecessary. You didn’t mention how often you are having the oil changed currently. But changing it every 3,000 miles is overkill unless your engine is old with a lot of miles on it. Follow your owner’s manual. For a 2005 Infiniti, the manual probably recommends doing it every 7,500 miles.

Question: I own a 2004 Ford Escape with a little over 72,000 miles. A couple weeks ago, the mechanic at a local garage I go to told me that I need to replace the engine. I was under the impression that car engines were built to last for over 100,000 miles. This seems really early. I could understand if I treated my engine poorly, but I change the oil every 4,000 miles and drive conservatively. I can’t imagine that I’ve damaged the engine. What do you think? Is it possible that I actually need a new engine?

Answer: Thanks for sending in your question, Andy. First, you’re right. Engines are supposed to last much longer than 72,000 miles. That said, given the details you’ve provided, it’s difficult to know whether there is an underlying problem in the assembly. Did your mechanic mention detonation, a persistent compression problem, or valve and piston damage? There are a hundred reasons he may have suggested a replacement, and it’s impossible for me to know whether his reason is legitimate. Sorry I couldn’t help more.

That’s it for this installment of the Auto Specialist. I’d like to thank Irv, Jennifer, and Andy for sending in their questions and allowing us to take a look. Make sure you come back next time when I’ll have a new batch of interesting automotive challenges to help diagnose. Until then, drive safely.

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