Early this week durring very hard rain my '86 Runner died suddenly. I was close enough to push it home where I checked the fuses. The EFI fuse was blown so I replaced it and tried to start it up. It started with ease, as usual, but died immediately. I checked the fuses again and the EFI fuse had blown again. I checked all the wires I could to find the short, cutting out and replaceing a few sections, but not finding anything in anyplace that might casue this problem. Each day I keep checking wires, replacing ground wires, checked inside the distrubutor cap for moisture. At first it blew a fuse ever time a put a new one in and tried to start it. Than, I took some bad advice and out in a 30 amp fuse rather than a 15 amp so that I could look for smoke to easier find the short. That did not cause any problems that I know of but I was not able to find the short. Since doing this I have the same problem of starting and dieing only now the fuse doesn't blow. Since then i've used 15 amp fuses.
When I turn the key to ACC or try to start it I get the brake and oil lights, I thought maybe I have a short at or in my alternnator since I read a post that said with an alternator problem you always get those lights. Any thoughts? I thank you in advance both for your time reading this and for any input you have. THANK YOU!

Josh-

 

Time to start poking around with a multimeter. Checking for Ohm's of resistance in the wiring to the ECU.

 

I totaly appriciate your advice but I don't really understand what to do the mulitmeter. I know that it has two metal "sticks" and one goes to one thing and the other goes to another, but I don't what any of it means.

 

You probe both ends of each wire to check Ohm's.

Pick out the wire you want to trace/check, then put the probes on the ends of that wire.

The higher the Ohm's, the more resistance the wire, or electronic device has.

 

ok, thanks very much!

 

Ok. I'm focusing on the fuel pump as that seams to be a likely candidate for the problem. I got down there and looked for the wires and found them. When I pulled them out into view water dripped out of one of the casings. I've made notes on some pics I just took.

What I am needing to know is if replacing the wires that got wet might solve the problem, if I need to also replace the yellow connector plug or I need to replace the entire wiring set up. Thank you for your advice in advance!

 

Bump?
Anyone know about this?

 

O2 sensor wire(s) are a common cause of EFI fuse blowing. O2 sensor is in the (hot) exhaust, wires have plastic insulation, one touches the other and poof goes the fuse. For the fuel pump, try the test jumper, that way you can turn on the pump w/o the engine running:
- http://www.4crawler.com/4x4/CheapTri...shtml#FuelPump

And how to use an ohm meter:
- http://www.4crawler.com/4x4/CheapTri...oUseAnOhmMeter

 

Just going to throw my two cents in here. Wet wires do not make a short unless there bare wires touching or close to bare metal or other bare wires. Thats why there insulated. The casing I take it your talking about is the one that both insulated wires are fed into to keep them together. Good insulated wires can get as wet as they want and not cause a problem.

 

Hey man, thats a big help! Thanks a lot!!

 

20RHeadBanger, Thats an excelent point and I thank you for making it! I just don't know where else to look.

 

I know (I think I know) that theres a short somewhere. When it died originaly, like a week or two ago, I checked the fuses and the EFI fuse had blown. When I replaced it she started right up but died immediately. The fuse had blown again. Now it won't start but the fuse isn't blowing anymore. I couldn't hear the fuel pump come on so I got in there and ran wires straight to the battery and it came on. I'm still hoping the short was in that wire. I tested the wire though and my light (test light) came on. I followed the wires and it went to the Engine Control box in the passenger's kick panel. Now I'm worried that that blew.

 

Ok. Few more questions, than i'm hoping problem solved, thread finished.
1-Can the 02 sensor be visualy inspected to a conclusion of good or bad?
2-If not is there a test that I can do to test it? or can a parts store or dealership test it?
I'd like to avoid buying a new one if its not bad.
3-Does my '86 Runner have more than 1 02 Sensor?
4-If yes, where? I can't find it. This one came from the exaust manifold.

THANK YOU!

 

Hello, I know little of these sensors and such but if they have two wires going to them you can do a continuity test between each wire and the body of the sensor. If both wires have continuity between the body of the sensor, I would say the sensor is bad. If you dont have a Ohm meter or multimeter you should be able to take it to any good electronic or auto part shop and ask them to do this test for you. Oh, by the way if it only has one wire, the test will tell you nothing. Too bad your not close by, I would be glad to help you out with this problem. It sounds fairly simple.

 

It is the wire(s) to the sensor, not the sensor itself that can short out. Follow the wires from the sensor (only one on the early trucks) and see if the insulation is melted in any place or if it is touching the hot exhaust manifold any place.

Sensor can be tested with a volt meter watching for at least 8 lean-rich voltage swings in 10 seconds of engine operation at 2500 RPM, details in a Factory Service Manual.

 

20Rheadbanger, Thank You. I appriciate your input and your willingness to help. I wish I was nearer too.

4Crawler, Thank you. Thats good to know. Unfortunately the engine wont run. for 10 seconds.

 

Finaly got her runnin tonight!

I've been at my wits end trying to figure this thing out for about two weeks now. Tonight, just now, I put in for one more go. I was trying to remove the driver's side kick panel fuse box and couldn't get it. I was reaching as far in as I could looking for the bolt or screw at the top. I couldn't find it. I puled some wires into view in an effort to expose the bolt and discovered some fuses I didn't even know existed. 2 Fuses inline with two wires. 1 was bad. Repalced it. Checked the rest of the fuses for the gazillionth time and found the Engine fuse to be bad. Replaced it. Fire, and Life!

At this time i'd like to say that when she first died I checked all the fuese in the kick panel, including the Engine fuse. Oh well.

Thanks for all the input I got on this issue!

I'm off for a drive!

 

Sometimes when we're in a hurry or just real flustered things dont show themselves or we miss them easily. Good luck and glad to hear you got her running.