OK, guys, I really need some help now. I am having some unexpected electrical issues in the truck all the sudden. Here's the story:

I started the truck this afternoon to do some A/C work. The engine turned over slower than normal and that reminded me that I need new batteries soon. I didn't think much about it as the crank speed wasn't THAT bad. I moved the truck to the garage bay area so I could have electricity for the vacuum pump to draw a vac on the A/C system before recharging it. I left the truck with the flashers and the radio on for about an hour. I came back, tried to start the truck and the engine turned over REALLY slowly. I said a few words about the situation out loud and decided to bring the 300SD over to provide a little jump start help. Well, it wasn't enough to get her started. I even tried not cycling the glow plugs, waiting a while, give a sniff of starting fluid but still not fast enough to start the engine.

After several tries every 15 minutes of charging on the 300SD and an hour later, I said F it. I put the battery from the 300SD in the truck. I disconnected the driver's side battery so there would be no extra drain on the system. As soon as I hooked up the negative terminal I got a lot of sparks and after a WTF! I noticed some smoke coming from the fender relay. I immediately disconnected the negative terminal. I felt the wires coming from the cowl-side of the two large relay terminals and two wires were noticeably hot. One went to the voltage regulator and the other to the starter solenoid located on the starter. The others did not seem hot. I disconnected everything except the starter relay from that terminal and hooked up the battery. Nothing arched or burned but I had NO power to ANYTHING. Not a big problem for an IDI and that is why I drive one. I touched a few other wires to the hot post and with one of them, the GP controller started smoking! Another and the VR started smoking! WTF! I'm lost. I realized I need to hook up a jumper wire to the FSS before I jump the starter relay with a screw driver between the two large posts on the fender relay. The truck cranked over stupid fast and fired off within a second. I said thank God, threw it in reverse and parked it in an open spot.

I tried not to hold any sparking wires to power for too long so as not to damage them. I'm not sure what to do now. Could it be a bad VR or fender solenoid? I have a feeling my GP controller is F'ed since I saw smoke from it.

I NEED THIS TRUCK TOMORROW to pick up some stuff from storage, so I would be very grateful of anyone can advise me on what to replace. I need to check the wires running along the fender by the passenger side battery as I may have disturbed them when I placed the 300SD's battery in. It's too dark out to look now.

Thanks, guys. I appreciate the help!

 

Oh, tomorrow morning, I am going out and purchasing the largest size batteries that will fit in this truck. I buy Interstate batteries because I have had really good luck with them. Any suggestions on group size is appreciated. I won't settle for less than 1000/850 rated batteries. I knew I should have replaced them a while ago and I'm not going to repeat this SNAFU any time soon!

Thanks!

 

Sounds like you isolated it to the relay on the fender. Check for bad grounds?

 

I have 1000/850 in my truck from oriley never had an issue

 

I would say something to do with GP relay on fender...my 1990 did this too. GP's were never the same til i fixed it. afterward....power was going to everything just fine.

I bought two 880 CCA batteries from Oreilly for 183.94(have receipt) almost two years ago, they are in the 83....and they still crank that thing over stupid fast.

 

hey thanks guys think i just figured out my problem hahahaha and i dont even have a motor in my truck atm will tommorrow but **** thanks

 

I don't think it's a ground issue, more of a "short" issue.
Something is taking power away from the starter and grounding out.
My guess, the VR.

 

Sounds like you hooked up the battery from the 300sd backwards and blew some fusible links.

 

I'm going out to the truck now to look at what is going on. I have a fender relay already, I'll pick up a VR and batteries just to be sure.

I'm pretty sure I didn't hook the battery up backwards because I double-checked the positive leads but it was dark out.

 

OK. I got two new Motorcraft batteries from O'Reilly's and a voltage regulator. I am finishing up the install of the fender solenoid I had as a spare and cleaning the connections / greasing them. I will hook up the hot wires on the FMS one by one starting with the main power lead. If I get sparks and or hot wires or smoke, I will post which wire is the problem and take it from there. I'm praying these replacements have solved my issue.

 

Well, I'm lucky! After replacing the fender solenoid, voltage regulator, and batteries, I had no more electrical issues. Not sure if it was the FMS or the VR but I am glad to have this fustercluck behind me.

 

Trying to start the engine with weak batteries may have welded the contactor inside the solenoid into the closed position.

 

^^^Thats what it sounds like happened^^^, you probably burnt some fuseable links at the starter relay,

 

If that were the case, they'd still be burnt.
Fuseable links need to be replaced when burnt.

 

i agree. bad batteries will do all sorts of weird things to solenoids.