A Tale of Two Idles

Before there were computers in cars, all it took to adjust the engine idle speed was a screwdriver and five minutes or so.

You turned in or out a screw that moved the throttle arm on the side of the carburetor slightly forward or slightly back, the engine idle speed going up or down  correspondingly.

Easy peasy!

Anyone could do it and such minor initiations into vehicle maintenance/adjustment often led to braver and deeper forays. Adjusting the idle was perhaps the next thing a teenaged kid attempted after successfully performing an oil change.

Today, it takes a toolbox to adjust engine idle and skills not-just-anyone has, especially people who’ve never learned to work on cars, like teenaged kids. Because how can they, when even the simplest thing is intimidatingly complicated to someone who hasn’t got skills or the tools.

My ’02 Nissan Frontier pickup needed to recently have its idle adjusted—not because it was too high or too low, a problem easily remedied in the pre-computer days by the turning of a screw, but because it’s idle was surging erratically. This was something that you fix today by cleaning or replacing components such as the Idle Air Control (IAC) motor, a device that is both mechanical and electrical and which has to be removed to be cleaned or replaced, if cleaning doesn’t work and if you want the idle to stop fluctuating erratically.

This is no single screwdriver and five minutes job.

On my ’02 Nissan, the IAC is screwed to the side of the throttle body with four screws—two of them inaccessibly offset mounted such that you can just barely see them and the only way to get at them is by disconnecting several peripherals, including the connections to two in-the-way fuel injectors and a fuel return line. Then, I have to at least unbolt the throttle body so as to be able to tip it back enough to get access to the IAC screws and then carefully unscrew these Phillips headed screws, which are made of typically Japanese soft alloy.

If the screwdriver slips or the + inset schmears, you’ll need to vise-grip or not-so-easy-out them out.

Two of the hex-head bolts that secure the TBI to the intake base are hard to get at because of peripherals in the way. These have to carefully removed, which you can accomplish if you have a toolbox full of specialty items such as skinny extender bars and other improvised (i.e., ground down with a grinding wheel) sockets that can shimmy through the space you’ve got.

All while being careful not to drop anything into the now-open intake manifold. Advice—put a rag down there while you work!

It’s more of a PITAS for the experienced wrench than a technical challenge. For someone without experience, the procedure might as well be a surgical procedure performed by someone who didn’t go to medical school.

Installation, once physically finished, isn’t the end of the job, either. Now you must go through a key on/key off conga ritual to get the IAC to “relearn” its job. In the case of my truck, this entails turning the ignition key on and waiting for precisely 2 seconds – you will need a stopwatch to be accurate—then off for 10, then on for 2 and off again for 10.

No, I am not making that up. And there are two other similar “relearn” protocols necessary to get the IAC and other related peripherals to remember how to do their jobs.

A job it used to take a screwdriver to adjust and maybe five minutes—no disassembly required. This job took me about 45 minutes and entailed disassembly.

Just one screenshot that helps explains why ordinary people, especially teenagers, working on cars has become so uncommon nowadays when it was once as common as checking the tires and the oil, two other formerly routine, once-simple things that aren’t anymore.

Some new cars don’t even have dipsticks. The computer checks the oil. And all cars built since the mid-2000s have tire pressure monitoring systems, chiefly the fallout of the ‘90s-era Ford Explorer/Firestone tire fiasco.

These TPMS systems are not as reliable as using a stick because they are electronic. Sticks don’t glitch. Electronics do. And you need more than just a screwdriver and five minutes to fix ’em!

Eric Peters lives in Virginia and enjoys driving cars and motorcycles. In the past, Eric worked as a car journalist for many prominent mainstream media outlets. Currently, he focuses his time writing auto history books, reviewing cars, and blogging about cars+ for his website EricPetersAutos.com.

Editor’s Note: The opinions expressed in this article are those of the author.

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