June 2016 Archives - UnderhoodService
Spark Plugs: Choosing A Heat Range

Choosing a set of racing spark plugs for a particular application is not as easy as it sounds because the plugs have to be closely matched to the application. Stock plugs are fine for stock applications and ordinary driving conditions. But when an engine is modified to make more power and is run under racing conditions, a lot of things change inside the combustion chamber.

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CARS And NACE: Training You Can’t Afford To Miss

CARS is no longer a training event. It is now an informational, strategic planning and networking event unlike any other. While there are classes, they have been restructured with a new model in mind.

Dodge/Chrysler Heater Hose “Y” Connector Prone To Cracking

Due to a high replacement demand, Gates engineers have developed a solution for the two-heater hose assembly “Y” connectors that are prone to cracking.

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Toyota Tech Tip: Rough Idle And Stalling

Some 2007 model year Avalon, Camry, Camry HV, and Solara vehicles may intermittently stall at idle or set one or more of about six DTC codes.

Odors In The A/C: How To Troubleshoot Smells

If you know someone who tells you that his or her vehicle’s air conditioner blows out air that smells like the inside of an old gym sneaker when the A/C is turned on, they are not alone.

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Head Gaskets: Q&A Session

Cylinder head gasket design has become more sophisticated than in years past. The following FAQs on head gaskets may give you a better understanding of why you need to pay attention when replacing a head gasket on a late model vehicle.

Why Does It Happen?

There are so many questions that need to be answered in our business. Some can be answered with a little background in engineering or technical information. Some can only be answered after a few visits with your local shrink. Other questions are just left in limbo for eternity.

Ford F-250: Check Engine Light, Code P0191

It’s OK to admit when you are stumped working on check engine light issues on F250s. You might not have figured out that the faulty powertrain control module caused fuel pressure to increase, which caused the engine to flood and the code P0191 to set. Don’t be afraid to seek help, and read this Real Fix to diagnose the vehicle.

Throttle-By-Wire Diagnostics

Throttle-by-wire is a standard feature on most late-model vehicles. Most of the time, the system is very reliable and usually does not fail completely, thereby leaving the driver stranded. Instead it “limps” along, letting the driver move at idle or at a restricted speed. Swapping a throttle-by-wire unit for a new unit hoping to resolve a code or limp-mode problem is not an option due to the high price and strict manufacturer return policies. Being able to think through and diagnose a throttle-by-wire problem is critical to working on late-model vehicles.

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Oxygen Sensor Replacement Basics

Did you know replacing worn or failed oxygen sensors is the best way to protect expensive three-way catalysts or catalytic converters? Failure to replace failed oxygen sensors at the earliest sign of a problem, usually indicated by an illuminated check engine light, can cause premature failure of three-way catalysts or catalytic converters.

Oxygen sensor
Parasitic Drain II: Jeep Grand Cherokee

As a general rule, a “parasitic drain” of less than 30 milliamps (mA) is normal for most vehicles 15 years old and newer. Keeping in mind that most manufacturers now publish parasitic drain values, let’s assume that a battery drain exceeding 50 mA is cause for concern.

Clicking Noise When Shifting Between Reverse And Drive Or On Hard Acceleration

Some customers may comment on a clicking-type noise coming from the front of the vehicle when shifting between reverse and drive or on a hard acceleration. Add a washer between the front wheel drive shaft and the bearing hub assembly using the procedure in this Tech Tip.