1972 Blazer starting issue - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tabs2471 · 12-01-2015, 11:59 AM

Hello all, I'm running into an issue I cannot figure out. My 1972 Blazer wouldn't start one day and I used my charger to charge the battery and started it up fine. Drove it for about an hour then parked it back home. While it was running I checked that it was charging and the alternator was reading 14.7 volts....felt good about that. Wouldn't start again. Since then, due to process of elimination, I have changed battery, cables, ignition switch, starter and solenoid! I even added a ground off the main ground from battery to alternator bracket....ran that to frame. I am absolutely at a dead end! It turns over real slowly and almost sounds like the timing is off. How could that happen when the last time I drove it, it ran fine. Almost frustrated enough to sell it at this point however I love the damn thing so no. Any help would be greatly appreciated.

cleszkie · 12-01-2015, 04:17 PM

Do you run an internally or externally regulated alternator? If external, have you checked your voltage regulator?

tabs2471 · 12-01-2015, 05:15 PM

I am using internally regulated alternator.....which is something I replaced last year. I am going to pull a few spark plugs and make sure there is nothing internal going on. Could it be timing chain? I would still think it would turn over normally even if the timing chain failed. Or I would hear it! Ugh.

franken · 12-01-2015, 09:37 PM

Step one would be to post the battery voltage. Sounds like a dead battery.

Ole Beater · 12-01-2015, 09:50 PM

The best place for the ground cable is right on the block so that the starter gets full 12v from the batter. I know you said that you tried different batteries but were they at 12 volts or better? You could also have a bad starter.

robs71k5 · 12-01-2015, 10:18 PM

Has it been converted to hei ignition . Maybe a fuse able link has fried

tabs2471 · 12-02-2015, 02:44 PM

I got a new battery yesterday after my 1 year old battery checked out bad by autozone even though it was fully charged.....still didn't fix the issue, I pulled the starter for the 5th time (new starter btw) and took it back to be tested...was good to go.....it does turn over but slow still.....I never thought about a fuseable link from the HEI, I will have to check that next as well as run my ground straight to the block. When it does turn over it just doesn't sound right either. No dragging on the starter, but as if the timing is off. I appreciate all the input. Hope to get this resolved soon.

12-01-2015, 11:59 AM	#1
tabs2471 Registered User Join Date: Aug 2014 Location: thornton, co Posts: 5	1972 Blazer starting issue Hello all, I'm running into an issue I cannot figure out. My 1972 Blazer wouldn't start one day and I used my charger to charge the battery and started it up fine. Drove it for about an hour then parked it back home. While it was running I checked that it was charging and the alternator was reading 14.7 volts....felt good about that. Wouldn't start again. Since then, due to process of elimination, I have changed battery, cables, ignition switch, starter and solenoid! I even added a ground off the main ground from battery to alternator bracket....ran that to frame. I am absolutely at a dead end! It turns over real slowly and almost sounds like the timing is off. How could that happen when the last time I drove it, it ran fine. Almost frustrated enough to sell it at this point however I love the damn thing so no. Any help would be greatly appreciated.

12-01-2015, 04:17 PM	#2
cleszkie Registered User Join Date: Feb 2003 Location: Santa Ana, CA Posts: 2,191	Re: 1972 Blazer starting issue Do you run an internally or externally regulated alternator? If external, have you checked your voltage regulator?

12-01-2015, 05:15 PM	#3
tabs2471 Registered User Join Date: Aug 2014 Location: thornton, co Posts: 5	Re: 1972 Blazer starting issue I am using internally regulated alternator.....which is something I replaced last year. I am going to pull a few spark plugs and make sure there is nothing internal going on. Could it be timing chain? I would still think it would turn over normally even if the timing chain failed. Or I would hear it! Ugh.

12-01-2015, 09:37 PM	#4
franken Registered User Join Date: Jun 2013 Location: Somewhere Posts: 3,103	Re: 1972 Blazer starting issue Step one would be to post the battery voltage. Sounds like a dead battery.

12-01-2015, 09:50 PM	#5
Ole Beater Registered User Join Date: Oct 2011 Location: St Petersburg, Florida Posts: 154	Re: 1972 Blazer starting issue The best place for the ground cable is right on the block so that the starter gets full 12v from the batter. I know you said that you tried different batteries but were they at 12 volts or better? You could also have a bad starter.

12-01-2015, 10:18 PM	#6
robs71k5 K5drive Join Date: Nov 2004 Location: burnaby BC Canada Posts: 815	Re: 1972 Blazer starting issue Has it been converted to hei ignition . Maybe a fuse able link has fried

12-02-2015, 02:44 PM	#7
tabs2471 Registered User Join Date: Aug 2014 Location: thornton, co Posts: 5	Re: 1972 Blazer starting issue I got a new battery yesterday after my 1 year old battery checked out bad by autozone even though it was fully charged.....still didn't fix the issue, I pulled the starter for the 5th time (new starter btw) and took it back to be tested...was good to go.....it does turn over but slow still.....I never thought about a fuseable link from the HEI, I will have to check that next as well as run my ground straight to the block. When it does turn over it just doesn't sound right either. No dragging on the starter, but as if the timing is off. I appreciate all the input. Hope to get this resolved soon.



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