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1991 Chevy Lumina 3.4 DOHC No Spark keeps blowing fuse on crank


Z34 Lover

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Hey guys im having a issue with the car, car just died taking off from the gas station and i got no spark. I got a crankshaft Sensor and im trying to figure out where it is but we checked fuses and i noticed a fuse in spot 10 which is 15 AMP IGN ( Under hood fuse box) keeps blowing everytime i go to crank after i replaced it. Any ideas on what it could be besides possible bad wiring? I got no idea what the fuse is tied to.

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When the Crank sensor went out on my 'ol Euro (3.1; and my brother was driving it when it happened) the car just up and shut off. There was no spark/ injector pulse. If your car had just that issue, I'd say start there. If you had no spark AND no fuel injector pulse, I'd put money on a crank sensor issue. BUT, since you indicate a ignition fuse popping, I'd look there first. Keep us updated.

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Hey guys im having a issue with the car, car just died taking off from the gas station and i got no spark. I got a crankshaft Sensor and im trying to figure out where it is but we checked fuses and i noticed a fuse in spot 10 which is 15 AMP IGN ( Under hood fuse box) keeps blowing everytime i go to crank after i replaced it. Any ideas on what it could be besides possible bad wiring? I got no idea what the fuse is tied to.

 

The crank sensor has no direct relation to the 15a fuse in the right side electrical center. THAT 15a circuit supplies feed to a few ECM controlled devices. If that 15a fuse is blowing I would suspect a short somewhere upstream or downstream in that wiring.

Just out of curiosity sake go into the glovebox and check the IGN/ECM fuse in there to see if it is still intact, if it is not then you may have a short to the ECM or the ECM itself may have an internal short.

 

If that circuit is good then fine, you're still going to have to begin tracing the paths of the items that the 15a IGN fuse in the RS electrical center supplies to find where that short is.

 

see the photos.......

 

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GP%20power%20distribution%20b_zpseuvbuyzq.jpg

 

with an auto trans car you won't have the manual trans bk/up lights & there won't be the 3.8 secondary cooling fan relay,

 

also, seeing that the engine will not start then you don't know if the alt is charging seeing as the field side of the alt is also fed from this circuit.

 

The crank sensor is located on the firewall side of the block, near the center just above the oil pan rail. It's awkward to get at seeing as you have to get around the trans axleshaft.

Edited by 55trucker
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  • 3 weeks later...

Good news i got the car to fire right up again. It was a mix between the crankshaft sensor and the ICM and coils. As for that fuse it no longer blows after i played with the wire for a while and traced it as far as i could and the wire was in great shape so not sure about what happened there. Now i got a new issue, soon as i started the car i noticed i got coolant dripping from back by the firewall. i had lost coolant before the car died. So i filled the radiator and went for a 7 mile drive. Got back and i put about a 1/3 of a jug back into the radiator. Car doesnt blow smoke or anything. What could be a possible cause for it? Its by the passenger tire in the front around the back corner of the block by the firewall based on how its dripping onto the ground. Any help would be great on this!

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Its more than likely coming out the drain hole for the heater core. Remove your center console (if you have floor shift) and remove the screws for the cover to the heater core. If the box its housed in is soaked with coolant and puddling there, then your heater core is leaking. Common problem and requires removing the upper intake to access the heater hose clamps to remove and replace the heater core.

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i noticed i got coolant dripping from back by the firewall. Its by the passenger tire in the front around the back corner of the block by the firewall based on how its dripping onto the ground

 

Pull the passenger side wheel, remove the fabric splash shield & shine a light up in there & take a good look at the heater return piping, it runs along the bottomside of the rail & swings up vertical at the firewall, they are prone to rotting, especially at the points where the mounting tabs are welded to it.

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When mine did that,it was the crank shaft sensor. It had cracked and did exactly what you are describing..I have a 92 z34 with 3.4l.The sensor was about 20 bux at Autozone,but is a bear to get to to replace..good luck.

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