Benjaminbvi4RUNNER

I replaced the fuel pump in my 1991 4Runner and now it will not STOP running, possible a person helping me hooked the battery up backwards for a moment while I stepped away. all ready disconnected the alt to check that it was not a diode stuck open, it is not. only way to shut the engine down is to unplug the negative cable. ANY ideas?

sexonwheels

....Faulty ignition?

MaK92-4RnR

so.. .you pull the key out and it stays on? i'd say its an ignition issue too.

Benjaminbvi4RUNNER

Thanks for your replys.
I have allready replaced the ignition switch, and same situation. I put the origanal back in and was able to return the new one. Now it is behaving different. when I remove the key rather than running on, it stutters and misfires then stops after about ten seconds and I have a check engine light now, I am going to put a volt meter on the Batt and see if the alt circuit is shutting down when the key is removed. I belive it may be related to the ecu.

SwampThing

Most likely ignition. When you turn it off and there isn't any more spark it should turn off dead. I mean it's not a diesel after all lol.

betelnut

x2. Even if excess carbon buildup were causing ignition when the spark plugs weren't firing, we're talking about a fuel injected engine here. No power to the ECU and injectors means NO FUEL.

Get out the multimeter and electrical diagram and see if there's a short somewhere.

Benjaminbvi4RUNNER

I have been trying to find the Electrical Diagram, but, have yet to find one. I am thinking there may be a transistor in the ecu that is fried (stuck in the ON position) or maby a relay controled by the ignition switch which is "welded" ON, it seems as if the ignition is in the on position when it is off, I am boggled. I am going to meter out some circuits and seach for a diagram. I really value all your feedback, Thank you all very much, we will see what is the culprit.......

betelnut

http://personal.utulsa.edu/~nathan-b...lectrical.html

betelnut

Sorry, that wasn't very helpful. Try this one:

http://didnt.doit.wisc.edu/offroad/T...unne/systemci/

Pull down eng3r.pdf.