got an old '91 4runner as a bush beater and ran into some trouble getting it started again. A friend of mone tried to boost (battery dead) at night and put the cables on backwards and it hasn't started since. If we hook up the booster cables and spray some gas into the air intake it will run off the gas but then die out. Tried putting on a new fuel pump, still no luck and checked the fuses too. Would the EFI relay fuse under the hood be the issue? Or the sender on the tank? Something else? Just frustrating that I can't get the pump pumping because it does run if you feed it directly in the air intake....

 

Try the fuel pump test jumper:
http://www.4crawler.com/4x4/CheapTri...shtml#FuelPump

Could be the fuel pump switch in the Air Flow Meter went out:
http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml

And for sure, check all the fuses under the hood and under the dash.

 

Check the fusible links in the wires coming from the + terminal of the battery.
Also, may be an ECU fried from the reversed voltage.

 

True but probably wouldn't run off of the ether if it was. Is your fuel pump getting voltage?

 

thanks wardriver, I didn't think of that.

check the fuel pump operation by simply inserting the key and turning it on, but not starting it. If you hear the fuel pump run, it's getting voltage. If not, you can connect a voltmeter to the FP terminal inside the diagnostic connector and the - terminal of the battery- you should get voltage for about 2-4 seconds when the key is turned on.