Hey there y'all, been browsing these forums for quite a long time and finally decided to make an account of my own!

Here's my rig, a 1991 4x4 pickup with the 22re:

(sorry if the pic is too big, I can't figure out how to make it smaller)

So this truck has been quite a piece of work since I picked it up over a year ago. When I first got it the engine didn't run at all and the wiring was totally jacked up, it took me 6 months to find a mechanic who was able to figure out what was wrong and get it running again. I believe the wiring in the EFI circuit was not correct but I didn't think to ask what exactly was wrong and the mechanic has since left town so I may never find out...

Since then I've had to replace the head on account of the old one blowing out a spark plug and destroying the threads, also installed a new timing chain kit, water pump and the whole nine yards, basically rebuilt the whole top end from scratch. It runs great after all the work I put into it, but still has a weird electrical issue that I have yet to figure out..

Occasionally it will crank but refuse to start. The first time it happened my buddy pointed out this little white and black wire going into the engine compartment fuse box and suggested I wiggle it around:



So I wiggled it around at the connection to the fuse box and sure enough the engine fired up almost immediately upon cranking the starter like it usually does. A few weeks went by with no issues and then it happened again..

Since then it's done this quite a number of times and every time I'm able to wiggle that little wire and it eventually will fire up. Sometimes it takes a few minutes of wiggling to get it to fire up, other times it fires up right away after the first set of wiggles. Sometimes it will go for weeks without ever having this problem and I'll forget about it only for it to do it again and remind me that the issue is still there. It doesn't seem to affect the engine at all while it's running, there was one single time where it died on me while running but I suspect that may have been caused by a different issue which has since been resolved.. 99 percent of the time when it's running it never dies on me, this almost always happens when it's been sitting for a period of time after running earlier.

Any of y'all have any ideas about what might be causing this issue and/or what that little black and white wire does? I've never been able to track down the source of this problem but I figured maybe one of y'all has experienced it before or may have an idea of what could be causing it. I'm pretty clueless when it comes to wiring and where I live it's damn near impossible to find a mechanic that actually knows their ˟˟˟˟. I used to know one but he moved to Texas so I'm ˟˟˟˟ out of luck there haha.

I wanna say thanks in advance for any help/advice y'all may have to give; I have to say this website is an invaluable resource for anyone who likes to do their own work on their vehicles. I would've had a hell of a time rebuilding my top end without all the awesome info this website contains and I'm eternally grateful that y'all are here! Thanks for being awesome and I hope my first post is a good one haha. If there's any more info y'all need just let me know and I'll do my best to provide it.

Sincerely, Cody (LordOfTheBuzzards)

 

Welcome to YT.
I bet if you look at the underside of the fuse box cover, just guessin' here, that wire goes to the starter relay. If so either end, or perhaps the wire itself is internally compromised or rusted thru, or the contacts on either end are defective. Maybe even the contact on that relay its plugged into is loose. but doubt that.

Second thing you should do is locate a wiring diagram for your year and such.
Also, look for Rad4Runner's posts on starter wiring. IIRC its probably a sticky in this forum. (But not going to go look). Its almost a bible on how these earlier models should have that done properly.
Its the book of Mathifications Chapter 1. Read those posts because its so helpful in understanding how/why Toyota does a lot fo stuff.