2007 Chevy Uplander no start
December 16th, 2016, 8:05 PM
#1
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2007 Chevy Uplander no start
Vehicle cranked over twice thursday night -30f windchill. Replaced battery, now it cranks repeatedly but no spark. Can hear the fuel pump running. Had alternator tested at AutoValue. Tester passed alternator at 12.8v set point and 11.8V dc output despite tag on alternator stating voltage set point of 14v. Had it tested at Napa, no output. Tested at O'Reilly, passed at 13.4v dc output. Coil pack secondaries have proper continuity, haven't been able to locate a pinout for primaries. Any help will be greatly appreciated.
December 17th, 2016, 12:40 AM
#2
as long as the battery is good and fully charged; a bad alternator will not cause a no start.
is it a waste spark system or 6 individual coil over plug set up?
test for spark with a spark tester.
if its waste spark, plug the spark plug wire over the grounded spark tester.
if its coil over plug;remove the coil, install the spark tester into the coil pack and grd the tester wire. crank the engine and check for spark...forget checking primary and secondary resistance and continuity...won't work with cop that have internal transistors.
is it a waste spark system or 6 individual coil over plug set up?
test for spark with a spark tester.
if its waste spark, plug the spark plug wire over the grounded spark tester.
if its coil over plug;remove the coil, install the spark tester into the coil pack and grd the tester wire. crank the engine and check for spark...forget checking primary and secondary resistance and continuity...won't work with cop that have internal transistors.
December 17th, 2016, 6:27 AM
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I appreciate your input however, I beg to differ on the alternator. A few years back, I had a Ford Escort with a bad battery, and a Subaru Forester with a bad alternator. Replaced both faulty parts, and still was not able to get either to fire. Replaced the alternator in the Ford and battery in the Subaru, both fired off and ran no problem. It seems if the charging system is not within spec, the computer does not get proper voltage causing a no start. As for spark, I did use a spark tester between the plug and wire earlier during troubleshooting to determine the no spark condition. As mentioned before, it is a coil pack not coil on plug. Found a post elsewhere referring to a no start condition after battery change, triggering the anti theft to disable the engine. Going to look into that next. Thank you for your time.
as long as the battery is good and fully charged; a bad alternator will not cause a no start.
is it a waste spark system or 6 individual coil over plug set up?
test for spark with a spark tester.
if its waste spark, plug the spark plug wire over the grounded spark tester.
if its coil over plug;remove the coil, install the spark tester into the coil pack and grd the tester wire. crank the engine and check for spark...forget checking primary and secondary resistance and continuity...won't work with cop that have internal transistors.
is it a waste spark system or 6 individual coil over plug set up?
test for spark with a spark tester.
if its waste spark, plug the spark plug wire over the grounded spark tester.
if its coil over plug;remove the coil, install the spark tester into the coil pack and grd the tester wire. crank the engine and check for spark...forget checking primary and secondary resistance and continuity...won't work with cop that have internal transistors.
December 17th, 2016, 9:19 AM
#4
i would love for you to put an alternator in then and post back.
the battery provides all voltage for every module while starting. the alternator does not produce voltage until the engine is actually running. If you have enough voltage to crank the engine at a least 250 rpm...and it maintains system voltage of at approx 9.6 volts while cranking...you have enough power to run all the modules. Alternators fail and yet people can still start and drive...until battery voltage get to low.
keep on chasing zebras
if you had a theft problem the theft light would be on, a theft dtc set in the body control module and the fuel injectors would be disabled.
the battery provides all voltage for every module while starting. the alternator does not produce voltage until the engine is actually running. If you have enough voltage to crank the engine at a least 250 rpm...and it maintains system voltage of at approx 9.6 volts while cranking...you have enough power to run all the modules. Alternators fail and yet people can still start and drive...until battery voltage get to low.
keep on chasing zebras
if you had a theft problem the theft light would be on, a theft dtc set in the body control module and the fuel injectors would be disabled.
Last edited by tech2; December 17th, 2016 at 9:31 AM.
