Blair

But I connected my battery in REVERSE!!!
My new '91 Runner had a weak battery. So, I took it out and charged it. Put it back in, in reverse polarity. Here's what I've done so far (and still no start)
Replaced the 80 amp fuse
Replaced the computer with one known to be working
Replaced assorted 'blade' type fuses.

I have good spark
My injectors are getting power
Fuel still not flowing

EFI relay is on order. Coming in the morning.
The Runner cranks, but will not start.

I CAN'T be the first to do this, so....what am I missing???
Thanks,

4x4Lamm

Isn't there a fuel system reset switch behind the kickpanel? Also, I know there is a reset switch above the gas pedal for something, a small white nylon push peg, give it a try.

Lamm

weldpro

Wow that really sucks! Another one of those live & learns........Man I am wondering when all the learning is going to pay off . Have you checked out the fuel circut in its entirety? My opinion is that all you need is gas (got spark & comp).
You'll never do that again.....
Richard S.

Blair

Just went accross the street. Tried two reset type plugs. No Joy...

95_4X4Runner

MY friend did something similar to his '90, he hooked up jumper cables backwards. I think he said something about replacing some diodes somewhere is what fixed it. I wish I could be more specific, but I wasn't there....

Blair

At this point I'm leaning toward a diode, or an open circuit relay. There is a small diode located inside the EFI relay, but externally it looks ok. Which doesn't mean that it IS, but there really is no other evidence of burning.
Keep the suggestions coming...

Duffdog

to test the diode, take it out and with an ohmmeter, measure it in both directions, it should be low resistance in one direction, and when you reverse the leads, the resistance should be infinite--if its not, you have blown the junction.

T

Cebby

There is a fusible link in the engine fuse box, can't remember what it's called. I had this problem on my Celica, years ago. Take a multimeter and check the FL's in there (check for continuity - you can do it without removing most of them)

Blair

If the diode were blown, would it be visible? I mean after having opened the EFI relay.

midiwall

With that much current through it, probably. I would suspect that there won't be much left of it, and the inside of the relay case will be a bit sooty.

aviator

Sorry to hear about the 'little goof-up' Blair. i'm going to see my mechanic tomorrow for a tune -up and oil change I'll ask him what the problem might be and post & pm an answer for you. Look at it this way I always have one accident and three boo-boos with every vehicle I've owned I had my accident a week after I got the truck (backed in to somebody on a dark night) and the busted lens inside so i'm almost finished... At least you're off to an early start...Hope its nothing too serious. Aviator

Duffdog

if the diode was blown, you might not know it or be able to see it. sometimes in HV equipment, the diode will turn brown from hi-temps, but sometimes ( like transistors ) there is no way you can tell. thats why they make multimeters.

T

Blair

THAT'S actually encouraging!
I can't see anything amiss. At this point I'm going to pick up the EFI relay early am. If no joy, it's back on the tow truck and off to the Dealership.

MTL_4runner

Unless there is a diode for the ECU as well that thing will be toast too.
Man, that sucks....sorry to hear about that!!!. :pat:

May be easiest to just bring it to the dealer and tell em what you did.
I am sure they have seen people do this before and know what gets destroyed when this happens.

Rennurder

I'm not knowledgeable with newer Toyotas but,try pulling the fuse for the EFI and leave it out for a good 15 minutes! This will give the ECU time to reset itself if its anything like mid-80's toys!????

Blair

I would have thought that too. But I opened the EFI relay and it's just simple copper contacts circuited with a small diode. The diode doesn't appear 'blown' and there is no soot.
However, when I replaced the EFI at 08:00 this morning it fired right up. The EFI sends an open circuit signal to the fuel pump. If the EFI is closed, no fuel.
No troubles driving, but now it won't start on it's own. Even with a new battery. No circuit somewhere, so I'm leaning toward a diode in the alternator.

Lot's a good lessons learned. Beyond the obvious :pat:
Still some electrical issues to troubleshoot, but when the runner starts, it runs really well.
Thanks for the input. Especially 4X4Lamm who knew about the fuel reset switches!

MTL_4runner

Are you saying it will crank but not fire?
....or that it won't even turn over?

All the diodes in the system are meant to protect against exactly what you did by accident.
You might want to get a wiring diagram and look for diodes in the system.
The relay had one, the alternator also has one, but there may be others.
I don't think the alternator will prevent it from starting but I could be wrong.

Blair

No. All is good now. Runs like a top. Another lesson I just learned...when you buy a new battery, you should remove the plastic terminal covers.

I'm not a wrencher, but I did the repair in the parking lot of the repair shop. Guy in the shop assures me it has to be the computer. So I ran up and got my old one. Take it to the shop, where my runner is sitting lonely in the parking lot. Nobody even put it on a scope. I install the computer. No Start. Only thing left was the EFI relay. Special order. Prepay. Had it in hand at 7:30 the next day. Swap the EFI's. Started right up.
Root cause of my issues was a bad battery created by poor connections and me hooking up in reverse after charging the weak battery. Cost of relays, towing and batery was about $200.

And you're right about the alternator diodes. There is a removable diode assembly on the alternator. You might start, but might not charge.

MTL_4runner

Sorry to hear about the experience but glad you're up and running again!

Blair

One of the best lessons learned was "How to be an Urban Street Mechanic" And that one of the biggest drawbacks to maintenance is the delay in parts. Next day is pretty darn good I agree, but it's very rare that I can get parts the same day. And I get my parts at a location within 10 km of Toyota's Canadian parts depot.

I'm just starting to get used to how this new used runner sounds and handles. Everything feels as good as my old one. No rude noises, the cursed 'funny tick' and a seemingly tight head gasket pending a replacement under V06. Body is A1, with that nice, solid, new feel when you shut the doors. Rear window was replaced with a whole new assembly. Typical body work done on the gate, really nice paint. Very glad I stuck with the 2nd gen but ehausted from searching for the right vehicle.