Everything goes dead while driving except engine

[Catterman]

My B2 has been sitting most of the summer, and now I am getting it ready to either sell or drive this winter. I am still having low fuel pressure at 20 psi, and hope to get my new fuel pump in this weekend.

For my question here, while I drive it, the whole truck will go dead! Gauges go to zero, radio dies, air/heater turns off, etc. but the engine and truck will keep running and driving. Then about 3-8 seconds later they all come back on... ANy idea where I start on this one???????

Thanks guys!

 

[adsm08]

Check all the connections at the battery cables. Disruptions there can cause odd electrical symptoms because the alternator isn't able to respond instantly to changes in load.

I used to loose the cluster and radio every time I flipped the turn signals on of switched hi/low beam, and that's what it was, a loose connection at a battery cable.

 

[RonD]

Check ground strap from head to firewall, that is the main ground for the instrument panel and other electrics attached to firewall.
Cab is isolated from engine and frame grounds, so needs a ground strap for reliable ground.

It is often forgotten or left off after work is done, then ground is via throttle cable and/or auto trans shift cable which can be intermittent.
Run a new ground from engine to firewall if you can't find the factory strap.

This diagram shows the 12v side of things: http://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_Powerdistribution_1991_2of7.JPG

Looks like the Brown wire and Yellow/light blue stripe wire coming from the power box in engine compartment, feed most of the cab fuse panel circuits, one of these wires could have a corroded connection.
If it was a short the fuse would blow.

My money would be on a ground issue, but I am poor so don't win many bets

 

[Catterman]

Thanks, I will check those out tonight.

Is the power distribution box located in the engine compartment? - or under pass side floorboard area (not sure why I think this...)?

 

[RonD]

Yes, engine compartment, on 1990 B2 it should be on passenger side inner fender well, black box with lid that opens.
Under this box are the EEC relay, Fuel Pump relay and the Wide open throttle(WOT) relay

 

[Catterman]

Didn't get to it... heading out of town so will try to get to it by Monday and will report what I find. Thanks!

 

[Catterman]

I found the ground strap, it was attached but the bolt wasn't the tightest. I torqued it down and then ran another wire for an additional ground strap. Drove it about 8 miles and no issues so I am hoping it is fixed!