So I posted this on the 4Runner forum I've been part of for 14+ years and they don't have a clue. Thought maybe getting some Bronco eyes on it wouldn't hurt.



Video of the issue is at the top. It's not throwing any codes. I'm about to grudgingly take it to Toyota.

Any help is appreciated.

Have you checked for fuel and spark. I've seen with some of the BMW's I work with that the engine control module gets damaged when people get the re connection of the battery incorrect.

Sounds like a faulty sensor not allowing it to start. I would start with temp sensors.

This is a long shot, but I have a Tundra with a K&N filter after changing a battery (optima) it wouldn't start sounded just like yours and I took the battery back it all checked good. removed the air filter and it started?? cleaned the K&N filter reinstalled and it worked. I never understood it but its been fine for years now.

I also had a 93 Toyota PU that would cut out randomly for no reason like the power switch was shut off, I would pull over and it would restart after several minutes, it took awhile to find but it was the EFI relay I guess when it got warm it would loose contact ? changed it and never had a issue. Is there a similar relay in the box you can swap?

I'd start with swapping the important relays with the less important relays. There is a chance that when it grounded it burned the contacts in the important relays(they would have energized as soon as the battery connected as just a self check). Inj. relay with wiper relay, ign. relay with headlight relay, etc. My guess is that, after extended cranking, they finally make contact enough to fire up and run but as soon as you shut it down they go back to a burned contact situation causing the issue again.

Like crawler is saying check your main engine & injection relays for power & ground.

Thanks guys. All good ideas. Today it got a bit weirder... Just now I was able to get it started...barely. This time I decided to drive it. I noticed that it was gutless along the entire power band so I kept driving. Little by little it got stronger, soon it felt more like normal. Shut it down, and it started right up again. Tried this a few times, started right up. Waited 20 min, started right up again.

I'm not 100% in the clear yet but my theory is that when I grounded the positive terminal, I completely wiped out all the ECU's learnt data. So it has to re-learn everything from scratch.

Test will be tomorrow morning when I try to start it.


Sent from my iPhone using Tapatalk

found your answer:

I think it’s fixed. Drove all around today and not one problem starting.


1970 w/Injected 427W