Hey guys, I've been racking my brain over this for a while now.





This is in my 88 'Vert.





I had a fuel cutoff switch connected to the 12v line that goes into the circuit opening relay that sits just under the steering column. The other day I ran out of gas (gauge doesn't work well,) so I added some more and tried to start it. It would start for about half a second and then die. I figured it was a fuel pump that went bad because I was cranking it without fuel, so I replaced the pump. Before I replaced the pump though i noticed that the LED on my cutoff switch wasn't coming on. This was odd since it WAS coming on a few days ago, even when the engine wouldn't start. After replacing the pump it still wouldn't start, so I set out to find the reason for the LED not coming on. I checked the circuit opening relay itself for proper resistance as per the service manual (page 4A-74 of the Engine Emissions NA Section,) the relay was fine, but the volts coming from the wires into the relay were non-existent. The Fp was giving ~10.5v in the start position, but nothing else gave any power in any key position. I tried Jumping the yellow test harness by the air filter assembly, and that made my LED flash once indicating a spike of power, but it still won't start. It just cranks and cranks and cranks. I was getting negative readings on the 12v power line, but they were negligible, only about .01 to .03v negative. The last thing I did was remove the switch and just restored the original 12v wire (called B in the diagram) to its original, non spliced-into configuration. I can see in the book/pdf that this particular wire connects directly to the ignition 1 power source and I'm hoping I haven't fried the wires somewhere, all of the accessories and lights work fine, it's just the fuel pump power delivery from what I can tell. Please help me, this is my daily driver and my boss is getting tired of picking me up for work. Any help is appreciated!



TL;DR - The wires going into my Circuit opening relay don't have the 12v they're supposed to have. They in fact have 0v and in some cases dip down to -0.01v to -0.03v.

 

Have you checked the fuse?

 

Thanks for the reply.



Yes, It's fixed now, sorry... I feel kinda dumb because that's exactly what the problem was. I had checked it a few times and it looked fine without pulling it out. The pop was further down the stem of the 15 amp section of the fuse, so it was really tough to see. I pulled it out just on a whim and there it was: a blown 15 amp fuse that kept my car down for 5 days...

 

Lol it happens man. It's easier to use a tester light on each side of the fuse while grounded to the body. If one side has power but the other doesn't then you know the fuse is bad without ever pulling it. All bus fuses have the two test points on the top for that purpose