April 2016 Archives - UnderhoodService
Spring A/C Repair Do’s and Don’ts

As vehicle owners in many parts of the country begin using their air conditioning systems for the first time this year, some will be surprised to find their A/C system is not functioning properly or isn’t blowing out cold air like the past summer.

Electric Water Pump Replacement

We recently had a 2007 BMW Z4 with the N52 engine in the shop. When diagnosing a faulty electric water pump, the first thing that needs to be done is to verify if there are any water pump-related diagnostic codes. There’s a very good chance there will be some. I then like to perform a visual inspection, but don’t look for the water pump from the top of the engine. You’ll want to drop the lower panels, and you will see the pump on the lower right side of the engine.

Plastic Intake Manifolds: Checking For Leaks

Most late-model engines come factory-equipped with plastic intake manifolds. Plastic saves weight and cost, and conducts heat much more slowly than aluminum or cast iron. This helps lower the temperature of the incoming air for a denser, more powerful air/fuel mixture.

Gonzo: Communication Is Key To Knowledge

Are there things mechanics keep to themselves and not tell other mechanics? I hope not, but I’m sure that even doctors and lawyers have a few secrets they’re not sharing with each other. The big secret is that there really are no secrets. What it really comes down to is knowledge.

Variable Camshaft Timing And Back Pressure Issues

The variable “valve” timing that most of us see in our shops is actually variable “camshaft” timing that ­improves low- and high-speed torque by advancing or retarding the camshaft timing on single overhead camshaft (SOHC) engine applications.

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Ford EGR-ESM Diagnosis

The EGR system module (ESM) is one of Ford’s latest EGR system for gasoline engines. It is an EGR valve, EVR, MAP and DPFE sensor rolled into one package. Though the DPFE sensor on an ESM is referred to as “DPFE” by the scan tool and also wiring diagrams, it is not a traditional DPFE sensor as used on the older EGR system. It is actually two separate MAP sensors.

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Your Shop Can Perform Most Services, Not Just Dealers

I have been seeing a lot more of these dealership-placed stickers on cars recently. It just drives home the point that the new-car dealer is your competition. These pieces of “propaganda” affixed under the hood of every car these dealerships sell reinforce a false belief among some consumers that independent shops can’t service late-model vehicles because they are too complicated.

GM Tech Tip: Interference Related To Aftermarket ALDL/DLC Device

Customers may comment on various issues with their vehicle related to high- or low-speed data bus traffic. The information contained in this bulletin is not meant to single out any one device or symptom, but to provide additional information that may be useful for diagnosing issues that do not have other diagnostic methods to identify the root cause.

Remote Diagnostics On Cars: The Future, Or Future Headache?

When I talk to technicians and shop owners about “remote diagnostics,” I find that there are many different levels of understanding as to what that term means. It’s clear that for many, the perception is that remote diagnostics means the ability to read codes. Well, if that is all we are talking about, it is true that a number of cars can generate a health report that includes things like DTCs, mileage and oil life.

Servicing Saddle-Style Fuel Tanks

Automakers have installed saddle-style tanks on several car models for more than a decade. This style of tank uses two wells, one on either side of a driveshaft or exhaust system. This position optimizes luggage compartment capacity, fuel volume and crash safety. The behavior of the fuel wells, pumps and sending units are often misdiagnosed, leading to fuel pumps being replaced unnecessarily.