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w3wilkes

Early 71 240Z Electrical Question

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Background... I've done the alternator upgrade using the MSA alternator / voltage regulator adapter and it works just great. I've also removed the mechanical fuel pump and installed an electric pump back at the tank using the pre-wired circuit and this also works great. In another thread regarding the alternator upgrade on a 73 240 there's a caution about cars with electric fuel pumps that can cause battery drain without an additional change.

The question... I jumpered the connector with an inertia switch in the console for crash protection. The connector in the console area gives power when jumpered to the pre-wired electric fuel pump circuit that's in all the 240Z cars. Do the early cars (pre 73) have the relay referred to in the other referenced thread? With what I've done with both the electric fuel pump and alternator upgrade is there a battery drain issue or am I good to go?

Edited by w3wilkes

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Probably more fun to study the diagrams, but I inadvertently developed a simple test for battery draw after modifying my 76 for an internally regulated alternator.  Look for a spark when you connect the negative terminal.  Seriously, a 0.3 amp draw from  relay will make a sizable spark.  I noticed it after I did mine, thought it was odd, then realized there was a problem when my battery was dead the next day.  In my case it was the brake warning lamp check relay.

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Didn't notice any spark when I hooked the battery up after the alternator upgrade which was done a couple of months after the electric fuel pump. I did drive the car after the alternator upgrade and then due to weather I left the car sit for about a week. The car started and ran fine. From Zed's description if I had a problem the battery wouldn't have lasted a week of sitting in the garage. As far as I know the after market radio and the clock are the only battery draws when the car is just sitting.

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