Scott "Gonzo" Weaver, Author at UnderhoodService
Lessons From A Day Being Out Of My Comfort Zone

Being under the dash or hood of the modern car is my comfort zone, but it doesn’t hurt to get out of that comfort zone. I could use a reminder now and then that what I do for a living isn’t all that bad, and I owe my customers a great deal of gratitude for their patronage and for putting up with this snarly old mechanic.

Electronic Throttle Control Diagnostics

A customer calls and tells you his car has suddenly went from highway speeds to idle. The check engine light is on, and no matter what he does, the car won’t go above 30 MPH. What’s wrong? Without looking at it we can only speculate, but I’ll bet it’s going to lead to a problem with the electronic actuated throttle system.

Shifty Battery Drain

Typically, when you’re doing a parasitic draw test, you watch the meter and wait for the amperage load to drop and the various systems to go to sleep. But on this truck, something was staying awake. Time for a different approach to the problem.

HFO-1234yf: Regulations And Requirements

SAE standard J2843, for “R-1234yf (HFO-1234yf) recovery equipment for refrigerants used in mobile air conditioning systems,” establishes the minimum equipment requirements for the recovery, recycling and recharging of R-1234yf.

Evaporative Vapor Emissions Control

These EVAP monitors can be run in two different ways. Ford, GM and some Asian imports use a vacuum to run the monitor. Chrysler, most European and a few Asian products use pressure to run the monitors.

Where’s That Machine?

Code numbers and definitions are a strategic direction for the repair. These tools allow a trained mechanic to know which pathway to take. The real “machine” that finds out what is wrong with a car is the brain of the very guy or gal working in the bay.

Second-Hand Information: When Critical Details Get Lost In Translation

Do you remember when you played the game of “telephone” as a child, and the original information being conveyed was often totally different by the time the last kid commented? The same thing can happen with a vehicle problem when more than one person is involved in getting the information to the person at the end of the line. And who’s usually at the end of the line? The tech.

Diesel Exhaust Particulate Filters: How Do They Work, What Do They Do?

The Diesel Particulate Filter (DPF) is a ceramic filter that has thousands of tiny channels or honeycomb-shaped openings that trap the soot onto the channel walls and prevent the particulate matter (down to 1 micron) from exiting out the tailpipe. The honeycombed inner structure is covered with a layer of a chemical catalyst that contains small amounts of precious metals, usually platinum or palladium.

Gonzo’s Tool Box: Cash Discount For Engine Swap Gone Wrong

In attempt to drum up some new business, I decided to run a cash discount promotion for large jobs thinking it might bring in new customers. It sounded like a good idea at the time, but the best-laid plans often go awry.

Alternator Testing: What Is The Correct Voltage?

For some alternators, it’s normal to see as low as 13 volts. For some, a constant 13.6 volts is an indication of a problem. For others, it’s normal to see as high as 16 volts for long stretches. Still, it’s perfectly normal for others to see the alternator not charge at all intermittently.

car-alternator-battery-charging-system
Electronic Throttle: Where’s The Cable?

Today, virtually every manufacturer has an electronic throttle system on board every make and model. That old throttle cable is a thing of the past.

The Importance Of Personal Preventive Maintenance

After decades of being behind the service counter, as well as under the hood, I do get a bit frustrated that people won’t do any preventive maintenance, or neglect to tell me about an intermittent problem they’ve had forever because they feel it has nothing to do with the problem for which they brought their vehicle into the shop.