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1985 eldorado biarritz convertible
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Discussion Starter #1
guys, i started my eldo just now to let her warm up... she ran for about 4 minutes and just cut out dead. i traced it back to a blown 10 amp fuse . i checked the wire loom to the tank and it seemed in good shape, i unplugged it and checked for any obvious signs of short. i then replaced the fuse and immediatly upon turning the key , it blew. this fuel pump is a brand new delco unit i had installed with a new sending unit.

do you guys have any ideas what may be causing this to blow like that?
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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6,737 Posts
Possibly the wiring harness at the oil filter area to the oil pressure sender? Its very close to the exhaust there. One of these wires keeps the fuel pump running once the car starts.
 

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1985 eldorado biarritz convertible
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151 Posts
Discussion Starter #3
thanks , i wil check it out tomorrow... its so friggin cold here this week !!!!

shes been running great and this is bumming me out
 

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1985 eldorado biarritz convertible
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Discussion Starter #4 (Edited)
i took a look around by the oil filter. no pbvious signs of wire damage. however up by the back end of the passenger side valve cover, there was som wiring (thicker looking red , two blue , one white). the red had compromised insulation , but the wire itself looked intact. i taped it up and made sure it was not touching anything. i tried again, and the fuse again blew immediatly upon turning the key. could it be the pump itself? it threw code #20 which is open circuit fuel pump. obviously must be a break somewhere i think. would a pump going bad throw the same code? where else should i look

thanks
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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An "open" is the opposite of a short. That code set after the fuse blew. Yes it could be a pinched wire anywhere from the dash to the pump.
 

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1985 eldorado biarritz convertible
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151 Posts
Discussion Starter #6
if the car was just sitting ther idling, do you suspect and particular area other than what you first mentioned?
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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That harness you unplugged behind the rear bumper passes over the top of the gas tank. If you didn't route that harness in the channel in the top of the tank, you might have pinched a wire upon reinstallation of the tank.
 

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1985 eldorado biarritz convertible
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151 Posts
Discussion Starter #8
ok , i got out the FSM and started down the troubleshooting on pages 8d1-22 and 8d1-25.. i entered diagnotsics and got a value of 9v in engine data parameter .1.0. i swapped relays with another of the same from the panel and tried again, still blowing the fuse. pretty sure its not the relay.
next step is to probe between 120 e / f and 12v. my question is where should i attach the aligator clip for 12v on the test light? can i go to the bulb socket on the courtesy light ?
and where is the oil pressure swicth , and oil pressure switch connector? FSM says to probe and observe the test light , im unclear at which points to do so. since they are cheap, i may go ahead and replace the realy and oil pressure switch. however if those test ok , the FSM says the short is in the 120f circuit and the diagram on page 8d1-22 inbdicates the "center bulkhead connector" is this a usual spot for a short? i assume its the big bundle behind the motor that feels like its impossible to disconnect. should i examine it from the inside of the firewall?
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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The wiring to the oil pressure switch is just above the oil filter where the switch is. A short is a wire with voltage in it that touches metal before it reaches the part its supposed to power. Rarely a part, most likely a bare wire touching metal either at the oil switch area or on the top of the gas tank. A short is checked visually. You must inspect all the wires that affect power to the in tank pump.
 

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1985 eldorado biarritz convertible
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Discussion Starter #10
carnut... you are my hero. we finally got a day here in north jersey above freezing.. so i dove into the problem. i was able to drop the tank with floor jacks (i dont want to do that again). i inspected that whole wire loom , but the only thing that was suspect was a butt connector for ground wires installed by the people who put in my fuel pump and sender. one end had two wire going into one and the connector wasnt covering all of the exposed wire. this tiny bit must have been causing the short. i installed a new butt connector , added shrink tubing over the whole thing. also , while under there i saw a white wire going into the level-ride connector that had compromised insulation and corrosion starting , so i fixed that too. finally buttoned everything up and gave it a shot... and SUCCESS! she started and ran great.

i love these forums !
 
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