SL/R107: 1975 450 sl Engine won't shut off. Help!
12-12-2013, 09:26 PM
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1975 450 sl
1975 450 sl Engine won't shut off. Help!
Hello,
I have a 1975 450 SL fuel injection v8. I just purchased the car from someone that said that it had been sitting for at least two years. When I hooked up a new battery I heard the fuel pump cycle and the alternator light on the dash lit up . The keys to the car were still in my pocket. I started the car, the alternator light went out and it runs and drives properly. Turned the key to the off position and pulling it out of the ignition and guess what - the engine stayed running! I pulled the battery cable to kill the engine.
I pulled the harness from the back of the key switch and the fuel pump still cycles when I hook up the battery. I then pulled the harness from the back of the alternator and the fuel pump still cycles when I hook up the battery cable.
On the front passenger wheel well is the battery cable junction block with an additional 10 ga wire under a nut. I pull that wire loose from the block and the fuel pump no longer cycles when I hook up the battery cable on the battery.
The million dollar question - what is causing the "key on" symptom when I hook up the battery.
Thanks, Bryant
I have a 1975 450 SL fuel injection v8. I just purchased the car from someone that said that it had been sitting for at least two years. When I hooked up a new battery I heard the fuel pump cycle and the alternator light on the dash lit up . The keys to the car were still in my pocket. I started the car, the alternator light went out and it runs and drives properly. Turned the key to the off position and pulling it out of the ignition and guess what - the engine stayed running! I pulled the battery cable to kill the engine.
I pulled the harness from the back of the key switch and the fuel pump still cycles when I hook up the battery. I then pulled the harness from the back of the alternator and the fuel pump still cycles when I hook up the battery cable.
On the front passenger wheel well is the battery cable junction block with an additional 10 ga wire under a nut. I pull that wire loose from the block and the fuel pump no longer cycles when I hook up the battery cable on the battery.
The million dollar question - what is causing the "key on" symptom when I hook up the battery.
Thanks, Bryant
