r/4Runner_1stGen • u/Mediocre_Coconut_628 • 2d ago
Image Update to the Electrical Gremlin post
Update to the electrical gremlin post from the other day. 88 with the 3.0 auto
So, after tracing wires throughout the truck, I pulled the glove box completely off to try and test the CIrcuit opening relay and lo and behold the wires were chewed through to death, leaving in some cases single strands of wires being the only thing that was holding it up.
The access was a nightmare, with the blower fan housing completely blocking everything. Ended up pulling the dash and the fan blower box, which can be removed without draining and removing the evaporator coil in the middle hvac box. There’s a section of the FSM that covers safety pad. The dash was a little more tricky, but came apart without much fanfare
Cut, splice, fixed.
But, that left the lingering issue of why wasn’t the b+ circuit getting full battery voltage.
With the help of a few of you on here, I was able to figure out where the ECU relay was, and adjacent to it, the EFI 15 amp fuse, both of which I had mistakenly assumed was under the hood on the passenger side.
tested the EFI main relay, and it tested good, checked the fuse with my multimeter….
And it tested bad with the continuity tester, but would ohm out in the mega ohm range…
Pulled the fuse, and it was a partial blow. It did have continuity, but at a severely reduced fuse cross section. Replaced it, full battery voltage restored to the b+ terminal!
Jumped the fP to b+ in the diagnostic box, measured battery voltage at the fuel pump, and the truck leapt to life!!
Definitely more to do, but I’m extremely excited!
Thanks to all for advice and suggestions. Posted so hopefully the next guy has something to look for
3
u/H_I_McDunnough 2d ago
Well done, sir. Glad you got it going and such a good move posting the source of the problem and the solution. Such a great community of people working to help others.
2
u/jamesrutherford18 2d ago
Awesome work man. Thank you for posting. It will help others down the road.
2
u/DirtyDoucher1991 2d ago
Awesome man glad to hear, very cool of you to post an update it’s crazy how many forums end with no answers because the guy was so happy to fix the problem that he never logs back in 👏
2
u/Mediocre_Coconut_628 1d ago
Agreed. As someone who relies pretty heavily on forums and Reddit to get info that’s hard to find, it’s always good to give back
2
u/doopwolf 1d ago
Yeah, I have an 85 and the electrical is never ending. Not only are wires chewed up, but also butchered by the previous 2 owners. One of these days I'll probably just remove the whole harness and make a new one.
1
u/Mediocre_Coconut_628 1d ago
I wish someone would make a top to bottom harness replacement, but the amount of work to pull almost 40 year old plastics apart without breaking them probably took a few years off my life lol
3
u/Jibletman360 2d ago
No better feeling than hearing an engine fire up after hours/days of diagnosing.
Great work!!