midwestbird

I have replaced several parts which have incrementally improved a rough running condition, but while my truck now idles steady, it still has a hard time starting when cold (cranks, sputters, stumbles for a few seconds). I read that faulty ground wiring can cause a hard start condition, which reminded me of this loose wire...



Between searching online, the Hayne's manual, the service manuals, and the Truck Electrical & Vacuum Troubleshooting Wiring Manual, I cannot find a good illustration of this wire connection. My understanding is that this wire ought to be grounded to body of the truck; I see a possible connection point for this wire on the body just forward of the battery - currently there are the remains of a rusted fastener where I suspect this little ground wire once mated.

It seems odd that the strands of the wire are exposed as they are; is there ordinarily some kind of connector at that point in the wire? The reason I ask is in the Truck Electrical & Vacuum Troubleshooting Wiring Manual, it appears to show some kind of connector on this wire:



Any info on this wire might help, thanks...
mwb

Steve83

That's not a factory battery cable, so that wire isn't factory, either. Replacements with that wire typically come with a yellow butt-crimp there. IDK why that EVTM shows the battery facing the wrong way, but it's not correct. Neither is the apparent connector it shows. And that cheesy battery disconnect isn't helping anything - you should get rid of it ASAP.

Also: having 2 black battery cables is dangerous (especially with the battery installed backward, like yours) because it causes confusion about which is the positive terminal. That can result in battery explosions & burned electronics, if someone connects jumper cables backward. I recommend you get a red cable, or at LEAST some red zip-ties on the positive cable ASAP. I also put red spray paint on the "+" on most of my batteries, so it's obvious. These show & their captions describe the correct way to install the battery:


(phone app link)


(phone app link)


(phone app link)

This album shows several common WRONG ways, and finishes with the right way to repair a battery cable terminal:


(phone app link)

midwestbird

I appreciate the input, but I can't seem to find an image of an 8th generation engine bay showing the battery oriented differently than mine. This guy's 8th gen seems to have the battery facing the same way as mine ( ), as does this one. (edit: Here is another: https://www.fordf150.net/forums/viewtopic.php?t=102482).
Conversely, images of 9th generation engine bays show the battery with posts in the rear (as does the '92-'96 image you linked). Based on the images I've seen, and the EVTM manual, and my 8th generation's configuration, it seems as though the orientation of the battery may have changed from 8th to 9th gen?

Can anyone with a 1987-1991 F-150 confirm how their battery is oriented/connected, and is there a small ground wire to the frame?

midwestbird

This is the neg battery cable NAPA shows for my year/model/engine.
This is what Rock Auto results for a 90 F-150 4.9L.

Steve83

Then the small wire must go to the green ground bolt on the core support between the battery & radiator. It just needs a heavy ring terminal, like the other rings under that bolt.