1999 GMC JIMMY

  • Tiny
  • Darrenbrandt
  • 1999 GMC JIMMY
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 180,000 MILES

When I start my 1999 GMC Jimmy the oil pressure gauge spikes up over 80 and stays there. Oil is fine and recently changed. How do I tell if I have a bad oil pump or oil pressure snding unit or a switch or other malfunction?

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Wednesday, April 20th, 2011 AT 11:33 PM

7 Replies

  • Tiny
  • Caradiodoc
  • EXPERT
  • 25,966 POSTS

Best place to start is by measuring the pressure with a mechanical gauge to see what you really have. I'd suspect the sending unit first but for a quick check, unplug the connector from the sending unit. If the gauge stays at maximum, that wire is grounded somewhere.

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Thursday, April 21st, 2011 AT 12:00 AM
  • Tiny
  • Wrenchtech
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Checking the pressure with a mechanical gauge is a good idea but with the labor time involved to do that, it may be cheaper and easier to just throw a new sender on it. It's cheaper than the labor time.

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Thursday, April 21st, 2011 AT 12:07 AM
  • Tiny
  • Darrenbrandt
  • MEMBER

Is the oil pressure sending unit easy to replace and if so where is it located at?

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Thursday, April 21st, 2011 AT 1:51 AM
  • Tiny
  • Wrenchtech
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That one should be in the back of the engine, next to the distributor. It just threads in but you may need a special socket.

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Thursday, April 21st, 2011 AT 1:55 AM
  • Tiny
  • Darrenbrandt
  • MEMBER

I took off the air intake and the distributor off and got to the oil pressure sensor to find that it was unplugged. I plugged it back in and that fixed my problem. Thanks for your help.

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Sunday, April 24th, 2011 AT 8:58 PM
  • Tiny
  • Wrenchtech
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I wish they were all that simple.

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Sunday, April 24th, 2011 AT 9:00 PM
  • Tiny
  • Caradiodoc
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No kidding. That choice isn't even on my dart board!

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Sunday, April 24th, 2011 AT 10:15 PM

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