Possible Alternator problem

George M

Original poster
Member
Jun 10, 2013
3
Wife primarily drives our 2006 GMC Envoy. It has 136,000 miles. New thermostat August 2012. New Battery October 2012. Cut off this past Saturday, while backing out of Garage. I thought I smelled antifreeze, but when wife returned home could not smell. Drove 30 miles or so on Sunday with no apparent problems. She called me today to advise that it almost would not restart after driving 15 miles and dropping daughter to summer day care. Ask her to keep an eye on gauge for charging system, try to notice how it is reading with/without ac on, using pwr windows, etc. She has not reported any more problems today. Is our alternator about to leave her stranded?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Welcome!

Do you have a voltmeter, even a $4.99 Harbor Freight cheapie, that you can get an accurate measurement at the battery terminals? Have you checked the terminal tightness? What does the dash gauge (as inaccurate as it is) read? Straight-up 14V?
 

George M

Original poster
Member
Jun 10, 2013
3
The Roadie:

I can check gauge and terminal tightness tonight. I think neighbor may have voltmeter also.
Will advise of findings. Thanks.

George M.
 

George M

Original poster
Member
Jun 10, 2013
3
George M said:
The Roadie:

I can check gauge and terminal tightness tonight. I think neighbor may have voltmeter also.
Will advise of findings. Thanks.

George M.

Hey Roadie:
Electrical checked out last night ok. Battery cables tight with no corrosion. Voltage reading steady at 14. Wife said it did not bounce around any when she was driving yesterday. Belt tight and still in good shape. What about cleaning the throttle body?

George M.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Cleaning the throttle body fixes a problem of erratic idle when the AC is turned on. The idle RPM drops when the compressor cycles on, and the engine can stall. This sometimes happens with no warning after a battery discharge or disconnection for any other reason.

When you said it wouldn't start for your wife, did she report HOW? If it just ignored it when she turned the ignition switch to START, then it could simply be a flaky ignition switch, which has a high failure rate for just this sort of flakiness. Easy and cheap to change. If it spun the starter and failed to catch, then it could be a sticky throttle body.
 

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