huskerrat Posted June 3, 2015 Report Share Posted June 3, 2015 My parents bought 3 720 2 are 82 1 is 84. They didn't consult with me before buying them lol. They are a mechanics nightmare cauase there's wiring hacks through out. I have gone through one and eliminated the carb hoses per a diagram I found. Now the issue I am having is it won't start. No click no nothing. It has good battery, starter getting 12+ volts. Its new. I can here the chime when I turn the key, I can here the fuel pump. But no gauges work, no blower radio nothing. So I decided to jump it with key on with screw driver and it came to life. Everything inside was working so I let it run for ten minutes then shut off. I went to start and nothing. Back to square one. That's when I replaced starter and still nothing. I found a wire and when I grounded it out I could here a something and it turns out it was turning on the the drivers side headlight, I then tested for voltage and it was showing 9V. But nothing inside cab works, except when it was running. I looked at the other 82 I seen the wire was attached to the bottom of the battery tray. So I am at loss for words on what too look for. I won't buy a car if I see wiring going every which it can. The spare one I think my mom is going to buried in cause she won't let me use it as parts truck its just used for storage. Glad to be here I am glad I own a 00 Saturn with 300k same engine same clutch plus 40 mpg. Easier to work on. Thanks for your help. Quote Link to comment
datzenmike Posted June 3, 2015 Report Share Posted June 3, 2015 My parents bought 3 720 2 are 82 1 is 84. They didn't consult with me before buying them lol. They are a mechanics nightmare cauase there's wiring hacks through out. I have gone through one and eliminated the carb hoses per a diagram I found. Now the issue I am having is it won't start. You say 'now it won't start'? Because if it won't start now, then it was something you removed with the hoses. Retrace your steps and find it. If you mean the current ongoing problem is it won't start, then trying to trouble shoot an electrical problem where absolutely anything could have been connected or disconnected by some previous hack will be difficult. Did it ever start and run? Or did it just start not to work? Quote Link to comment
huskerrat Posted June 3, 2015 Author Report Share Posted June 3, 2015 The one I took the hoses off the carb is my dads, and it runs fine. His is the 84. The one I am working on is my mom's its an 82 and yes it was running. It has wires hanging under dash and inside engine compartment. The fuseable links going to battery were corroded so I stripped them and now are on the battery cable. My dads is set up the same way. These trucks aren't dd they just use them to haul wood and hay. I tried jumping it again with scew driver but got nothing, every time I tried I could here the chime from the ignition come on stronger. Just puzzled. Quote Link to comment
huskerrat Posted June 4, 2015 Author Report Share Posted June 4, 2015 Well I worked on it again today and found out that the body ground has 12V running through it. So does the valve cover, the fender and brush gaurd. So somewhere there is a positive connection. I mananaged to narrow it down to when the ignition is on cause I took off wires to headlight, then headlight relay. So now I just need to figure out where the problem is. Anyone want to help rewire lol Quote Link to comment
datzenmike Posted June 4, 2015 Report Share Posted June 4, 2015 There should be a ground strap from the negative battery terminal to the body near the battery. Check the '84 and see. The negative cable grounds to the intake near the thermostat. Quote Link to comment
huskerrat Posted June 4, 2015 Author Report Share Posted June 4, 2015 This one doesnt have it just grounds to the intake, I did see it on the other 82. Ground strap to battery tray, then to intake. Should I do the same thing for this one? Quote Link to comment
datzenmike Posted June 4, 2015 Report Share Posted June 4, 2015 Yes. The engine is somewhat isolated from the body... rubber engine and transmission mounts, rubber hoses, rubber on the shocks, rubber eyelets on the leaf springs and exhaust. The body has some electrical things like lights that are ground return. The body must have a ground strap on it. Make it a 12 gauge at least. Quote Link to comment
huskerrat Posted June 4, 2015 Author Report Share Posted June 4, 2015 Will do when hopefully this will correct the issue. Quote Link to comment
huskerrat Posted June 10, 2015 Author Report Share Posted June 10, 2015 Thanks it worked took the other ground strap off and it started, tested alternator it was putting out 10V, its a reman I think the other is original,I am going to have it rebuilt before it goes in. It looks like a chore to get it out. Quote Link to comment
huskerrat Posted June 11, 2015 Author Report Share Posted June 11, 2015 Well the alt was easy to get out of the spare truck, it's the original made in Japan so going to have it rebuilt. That way there won't be any problems in the future with alternator. That is for everyone's help will keep up with updates. Quote Link to comment
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