I have a 1987 gmc sierra classic with a 6.2l diesel. I am fairly new to diesels so not really sure what is going on. My alternator belt broke and i replaced it plus one of the batteries. after installing belt and new battery i tried to turn the motor over and all it does is click. i pulled the starter and had it checked at the auto parts store and it says it is ok. I am thinking it might be the ignition switch but not really sure. Any advice on what i can do?????????????
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1987 6.2L wont start!!!!!!!
- Thread starter Mwerth32
- Start date
bison
Well-Known Member
Welcome to the site.
for starters,
Maybe check and clean all batt and ground connections.
Have both batts load tested,....new don't mean they are always good.
for starters,
Maybe check and clean all batt and ground connections.
Have both batts load tested,....new don't mean they are always good.
You only replaced 1 of 2 batteries, why? Perhaps they are 6 months or less old? The diesels take 2 batteries and are hard on them. Cranking speed is critical. The old battery will drag the new battery down and shorten it's life.
Regardless you get a click when you turn the key. This means the starter solenoid is getting power. So ign switch etc is OK. Test it if you want:
1) 9v or more at solenoid terminal when turning they key.
2) 11v or more at main battery terminal on starter.
Possible problems are:
Bad positive cable to starter. Bad connection at positive battery cable. Bad battery grounds. Bad battery taking good battery charge down, bad starter Intermittent.
So I would check the battery cables and connections. Then load test both batteries - making sure to disconnect them so you read each one. Look for stiff cables from internal corrosion from acid leaks from batteries. The positive cables are very prone to this.
Assuming the voltages are good as noted above or because you have the starter out already I would assume the starter has a bad solenoid. Replace the starter. I had one that would spin 3 of 4 tries clicking the 4th try. Again the battery question needs to be answered first.
Regardless you get a click when you turn the key. This means the starter solenoid is getting power. So ign switch etc is OK. Test it if you want:
1) 9v or more at solenoid terminal when turning they key.
2) 11v or more at main battery terminal on starter.
Possible problems are:
Bad positive cable to starter. Bad connection at positive battery cable. Bad battery grounds. Bad battery taking good battery charge down, bad starter Intermittent.
So I would check the battery cables and connections. Then load test both batteries - making sure to disconnect them so you read each one. Look for stiff cables from internal corrosion from acid leaks from batteries. The positive cables are very prone to this.
Assuming the voltages are good as noted above or because you have the starter out already I would assume the starter has a bad solenoid. Replace the starter. I had one that would spin 3 of 4 tries clicking the 4th try. Again the battery question needs to be answered first.
Thank yo so much for the help!!!! I have had the positive battery cable on the passenger side replaced already. i will replace the other positive and both grounds this weekend. I had the starter tested and it says that it is good but when the arm pops out it pauses for a second and then starts to spin but slowly. I am going to replace that also. the guy i bought it from did not keep up with it very good at all and i am having to fix a lot of things on this truck. i will post back after I get everything done with the results. Once again i appreciate the help. You cant beat a diesel!!!!!!!
Possible worn out brushes in starter motor causing the motor to stall with a load. They do not put a load on starters to test them. I have had good luck with Autolite starters and the all new Powermaster starters. The Powermaster is the way to go if you can wait for it to arrive.