Brand new member...joined after reading a bunch of quality posts on this site. So...my dual tanks quit switching and the gauges pegged out to showing full tanks. so I took it to the local dealer. 1987 F250 6.9 diesel that even though it's not fast it's a great truck. It always started fast, even in the winter. Got it back and noticed right away that the starting seemed sluggish. Backing up a little, realized my fuel diverted valve was bad because I ran out of fuel. Had to bleed the line at the filter afterward to get it to start well. So I get it back and noticed the next morning that it seemed to turn over slower and didn't catch/start fast like always. This went on a few weeks and finally took it back to Ford. They called the next day to tell me the batteries were bad...had replaced both when I bought the rig 16 months ago. They also told me my glow plug harness was bad. They replaced the glow plugs a year ago. So the harness is on order from a guy on EBay that makes them since they are a hard part to source. When I got it back with the new batteries it started like before. Over the next few days it slowed up again. Now it's starting even worse. Feels like the batteries are low again. White smoke at startup, I feel like the volt gauge is acting different. Not returning as high as before the problems started. When I turn the key to start glow plugs warming, the light goes out faster and than I hear clicking. We're should I start? Bad starter and a couple glow plugs? Bad harness like they said? Alternator failing?
After it starts, if I shut it off and restarted a few minutes later it would turn over fast and start fast. What's upsetting is the dealer for the typically high cost now seem to not really want my business, the truck is too old...any idea's? Or a good troubleshooting chart? I don't want to just throw parts at it.
Thanks for any help
Kevin

 

Kevin, are the battery cables in good condition? The terminals should be free from corrosion and the cables shouldn't be frayed.

You can test the alternator at the parts store or with a voltmeter. The battery should be charging at 13.8 V with the truck running.

 

thanks, I'll get those 2 things done...I had a olds 1961 dynamic 88, $150.00 from the orig owners in 1985...had waterbumpers front and back...lol