Hey all,

89 F250 7.3 ZF-5, Manual GP button, Push button starter

So the other day I went to start my truck, warmed up the glow plugs, then attempted to crank it and everything just died. No electricity to the dash or ignition. I took my other vehicle to work and let it sit overnight. The next day I attempted to start it again, and I had power to the cab and ignition. Hit the GPs again, and attempted to start it, and nothing. I inspected the fusible links on the Pass. side fender and found one wire that was burned up, but It was after the fuse section. I replaced that today and was able to start the truck right up. After a few minutes I turned the truck off, let a few more minutes go by, tried to start it again, and nothing. No power to the cab or ignition. No other fusible link wires seem to be damaged. Every time I let it sit for a few minutes, I'll have power to the dome light.

I cleaned off the ground terminals on the block, and it was able to start right up again. Then I shut it off, let a few minutes go by, tried to start it, and same thing, no power to cab or ignition. I then replaced the starter relay (or solenoid? The one on the fender), and got power to the cab and ignition, but when I hit the GPs, no more power again.

I should mention that I have 2 refurbished batteries (all I could afford at the time), but they are reading 12.7 volts. When the periods of no power hit, I could hear a slight "fizzing" coming from the Pass side ground terminal, but when I did have power, there was no sound (key on, engine off). There is plenty of water in the batteries. I'm kind of leaning towards the batteries being the issue, and am going to have them tested tomorrow.

Cables to the starter seem to be in good condition.

Any other ideas, or something I should look out for?

Sorry for the essay, just trying to paint a good picture.

Thanks

 

Make sure all the connections are clean. Battery connections especially.

 

I was just reading more into that. I hit them with a water/baking soda combo and dielectric grease today. Steel wool or something tomorrow

 

Your rig is old enough where cables and connections start getting wonky. It won't necessarily be visible corrosion either, though if there is the connection will soon fail altogether. Clean, shiny bright and tight, is crucial. Cables are crimped to the terminals and start getting high resistance. But it won't measurable per se. The best advice is to simply replace the battery cables and ground cables as they are now over 25 years old. Test them first, but there's not much point.

Because of the high current involved with starting cables and the rest of the charging and electrical system, cables and connections can only be tested under load, for voltage drop, during engine cranking for example, or alternator testing with headlights on and blower motor, etc. By placing a voltmeter in parallel across a cable or connection a positive voltage will be generated under load representing the amount of voltage loss. Anything more than a few tenths of a volt is excessive and enough to throttle back the alternator charging significantly, or keep engine from cranking etc. Here's how to test:

http://www.aa1car.com/library/voltage_drop_testing.htm

 

Battery voltage means little, and actually means nothing while both are connected. LOAD test the batteries, in isolation.

 

Update:

I cleaned the heck out of the batter posts and connectors, and she started right up. The funny thing was, my P side battery was reading 14.3 volts, but my D side initially read 12.6, and then eventually went up to 13.2. I haven't done a load test or anything, I just wanted to try the easy stuff first. I guess I could switch the batteries, try again and see if there's any change.

I think new cables and batteries are in my future. Just to be safe.