Hey guys, I recently bought a 89 Toy pickup that had a 3.4 out of a 99 4Runner swapped into it. Drove it approx 250 miles from where i picked it up to home with no issues. Not too long after it started making a horrible sound from the passenger cylinder bank like a bad exhaust leak. Remove valve cover and the spark plug is laying in the tube, not threaded in the seat. Pull the plug out and there was a thread repair done to the head that was no longer there, it was still on the plug. So I replaced the cylinder head which was a big PITA. Today I get everything bolted back up, torque'd to spec, and change all the fluids. I went ahead and changed the plugs while I was at it. Also replaced the coil pack and boot over the bad plug. I fired it up before I had the O2 sensors back in the exhaust just to see if it would run. It started up and idled ok without throwing the CEL (yes it works). So I put the exhaust pipe back on and attach the O2 sensors and go to start it up, no luck. And, to top it all off, when I turn the key off, the fuel pump stays running and the CEL comes on and stays on even with the key out of the ignition! Any thoughts or guesses on what in the hell is going on? I also can't remember where this plug goes




It comes across the front of the motor and comes out of the wiring harness that continues to the cam position sensor (I think)

Here's where it comes out of the harness


I don't think it would prevent the motor from running, as I already had it running earlier. Also, I am completely stumped on as to why the fuel pump is statying on after the key is turned off as well as the CEL?

Thanks guys.

 

I believe that's the a/c compressor clutch wire.

 

That would make sense seeing as how I don't have AC. I couldn't remember if it was hooked up or not. Thanks

 

Sounds like you must have pinched some wires when you put the exhaust back up. Or during the head install.

So when the O2 sensors were plugged in it caused these issues.

What else did you do after you had it running and shut it off.

Since you had the battery disconnected all the tests would need to run again.

Did the CEL come on like it should when you turned the key to run like it should.

What code is it throwing now??

With these engines a code reader is almost a must.

 

Update: Truck started up just fine after sitting for a while. Idled ok, throttled up ok, then died and wouldn't start again. Definetley a fuel issue. CEL comes on only after the key has been turned off. I do have a code reader, guess I'll throw it on and check everything out. Thanks

 

pull your battery cables off and let it sit for a little bit. running it without the o2 could have thrown the fuel calculations off in your ecu, pulling battery cables will reset that to factory (not the corrected settings it's trying now)

 

Niall, you were exactly right. After letting it sit overnight with the cables disconnected, it fired right up and everything was good. Hard to believe that running it without the 02 sensors would casue the pump to run and the CEL to come on AFTER the key is shut off. Thanks for the help!