Blowing EFI fuze and hot EFI relay in engine fuze box
 

I was drivin down the road mindin my own buisness then. My truck dies. I creep over to the side of the road.:(

The Good-
It turns over no problem.
All the lights work.
Everything has good clean connections.
Radio works
Blows air through the vents
All fuzes in the Junction block #1 by the driver side kick panel are good.

The bad-
Blown EFI 15A fuze in engine bay fuze block (relay block #2)
Hot CMH relay (C in relay block #2) i replaced this with a new one and the new one also gets hot (when the key is left in the ON position). I also replaced the EFI relay (B in relay block #2)

The EFI fuze blows/pops the second the ignition is turned to the ON position(the position just before START when it starts crankin the motor)


When this fuze blows there is no spark i have a spark checker that goes in between the distributor and the spark plugs and there is just no spark when this fuze blows.


QUESTION
I figure there is a definate short somewhere just wondering if anyone has ever encountered something the same or similar to this. I have pulled the relay block up from the fender wall and removed the bottom to look for chaffed wires they all seem to be in good condition. My mechanic friend sais sometimes the solder on the connections by the ignition can get hot enough to melt and ground each other out. I am at a loss right now. And have gone through more fuzes than.....someone that goes through a lot of fuzes. i have tried everything from 15A up to 30A they all pop just the same the second the key is turned to the ON position.
Attachment 184102

There's actually more then a few threads like this..

Some dealing with bad COR's..
Mine had to do with bad wiring inside the fuel tank (dont ask)
More common ones have to do with the 02 sensor wiring shorting out due to melting from heat from the transmission..

Use the advanced search feature and check in the 86-95 folder search quote "15A* EFI* fuse"
make sure to use the asterisk as it will search for 3letter words with them. Good luck.


:dj:

i tried searchin but i'll look again

Thanks for the hint on better searching this topic. i read your old thread about the gas tank. no bueno. i think im gonna start with the o2 sensor and go fromm there thanks a bunch. sounds like there are many causes of this problem:hillbill:

Yes there are many causes..

Oh, Theres no refrence to which engine were talking about !?

IMO it could be the COR

Look through This page, At the bottom of the next topic it says things about the Circuit Opening Relay.
It shows a diagram and how to test it..

:dj:

Oh, And dont put bigger fuses in, Thats a :fire2: waiting to happen..


:dj:

Its the 3.o its in my signature

hhmm, I believe electronics are still mostly the same..

:dj:

BAM problem found and solved. thanks for the hints on searchin SCUBA i got a serious problem with the o2 sensor wires so for now i just cut them wrapped them up in electrical tape and zip tied them away from anything. How will no o2 sensor affect its drivin abilities
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aww snaps .. haha i didnt even knowtice that when we were puttin ur cat on. iv never driven with one disconected.. i know its gonna throw a code and kick ur check engine light on.. hell that was probably the reason u havnt got it to pass at DEQ. have fun replacing that, lots of soaking with pb.. hopefully you wont break the bung loose like my brother did on his old yote lol

All I know is, when my 02 sensor went out, it was backfire casserole, with a side of hesitation and no power!

O2 sensor
 

My EFI fuse keeps blowing as well and i believe that it is due to my O2 wire making contact but i do not know where the O2 sensor is exactly. Any diagrams?

O2 sensor is critical