TribLIVE

| Business

 
Larger text Larger text Smaller text Smaller text | Order Photo Reprints

Oil gauge gets case of jitters

Email Newsletters

Click here to sign up for one of our email newsletters.

On the Grid

From the shale fields to the cooling towers, Trib Total Media covers the energy industry in Western Pennsylvania and beyond. For the latest news and views on gas, coal, electricity and more, check out On the Grid today.

'American Coyotes' Series

Traveling by Jeep, boat and foot, Tribune-Review investigative reporter Carl Prine and photojournalist Justin Merriman covered nearly 2,000 miles over two months along the border with Mexico to report on coyotes — the human traffickers who bring illegal immigrants into the United States. Most are Americans working for money and/or drugs. This series reports how their operations have a major impact on life for residents and the environment along the border — and beyond.

By McClatchy-tribune News Service
Saturday, June 29, 2013, 12:01 a.m.
 

Q: My oil pressure gauge has begun to get the jitters. It seems to work normally for a while then jumps around like crazy when I speed up from a stop. The truck is a 1998 GMC half-ton. Could this be an engine problem or just the gauge?

— Alex Fuller

A: I'd start with a check of oil level and condition. Low oil level could cause the gauge to intermittently drop out, perhaps on turns or acceleration. Also, it doesn't hurt to check for dilution or contamination. If color and thickness seem OK, we'll move on to the gauge.

Vehicles that have an oil pressure gauge employ a sending unit, threaded into a port on the engine. Yours is thumb-size and black. It's located toward the top and rear of the engine, near the base of the distributor, and has a single tan wire attached to it. The sending unit contains an electromechanical mechanism that varies in electrical resistance in response to oil pressure. Sending units can be flaky and sometimes leak oil.

When an oil, temperature or oil pressure gauge fails to work at all, a neat trick is to disconnect the sending unit wire and look for the gauge response — many will read zero. Next, grounding the appropriate wire at the sending unit typically causes the gauge to read high/full, or hot — probably a bit past the upper limit, though some gauges respond in the opposite direction. If the gauge shows these two characteristics, the fault lies within the sending unit.

If your oil pressure gauge is the only one of its siblings to act erratically, my money is on the sending unit or perhaps its electrical connection. Verifying the cause of a jittery electrical signal is a bit tricky to explain and do, making replacement of the sender a very high-odds $50 gamble.

Electric door jam

Q: All of the functions in the driver's side door of my 2004 GMC pickup have stopped working, but sometimes will come back, but only with the door open. Any ideas before I take it in for repair?

— Tom Lindquist

A: Tom, I have a hunch your truck may be suffering from a broken wire in the bundle that enters the door from the A-pillar. With the key in the run position (engine off) and door open, try depressing and holding a window or door lock switch as you gently wiggle/massage the black rubber boot, which is about 1.5 inches in diameter and located just below the upper door hinge. If normal operation occurs, even briefly, this tells us there's trouble inside the boot.

Disconnecting/pulling the boot back from the pillar will allow a peek at the wire bundle within. Look in particular for a broken orange or black wire. If a wire repair is needed, splice in a 6-inch length of wire, looped, to lessen flexing and strain on the repaired connections. Solder and shrink-wrap — no crimp connectors here!

Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers may send him email at under-the-hood@earthlink.net; he cannot make personal replies.

Subscribe today! Click here for our subscription offers.

 

 


Show commenting policy

Most-Read Business Headlines

  1. Cuts at Range Resources include layoffs
  2. Travelers find direct Web route to Priory’s spirited past in North Side
  3. Post-Gazette offers voluntary buyouts in bid to avoid layoffs
  4. Plastics propel Bayer’s 2Q earnings
  5. Muni bond funds stressed
  6. PPG puts brand 1st in strategy to reach commercial paint market
  7. U.S. Steel posts quarterly loss, declares dividend
  8. EPA ordered to ease limits on cross-border air pollution that involves Pennsylvania
  9. Bayer sets sights beyond aspirin
  10. Pa. improves performance among competitive electric markets
  11. Chronic job-seekers giving up the hunt