New Guy Here, I Need Help With My 85 Gt

Wgfl_dylan

New Member
Feb 8, 2016
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I have an 85 gt with a 351 Windsor and a Holley 750 with MSD ignition, my problem is the car dies when I put it in gear or if I turn on my lights, or my heater or my fans that cool the engine, I just bought a new battery for the car and it runs fine when it's in park or neutral so idk where to start and I thought you guys could help, thanks
 
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My first thought would be to check all of your grounds. If your not getting enough voltage to keep the coil lit then you're going to have problems.
 
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Beg or borrow a voltmeter . Set the scale to the closest range greater than 12 volts DC and connect the voltmeter across the battery. Start the car and watch the voltmeter; you should see 13.8-14.2 volts. Since it may be cold where you are, it is ok if it runs above 14.2 volts. Add electrical load and watch the voltmeter. It should only drop .1 from to .3 volts from the 14.2 volts peak.

Report back what you observed and we will proceed from there.
 
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Think about it- when you put any load on the car it dies, and it happens when you move or when you add a load. Sounds like a bad ground that is loose or damaged. As Jrichker suggested, get DVM and start doiing a volage drop across the primary circuit and then for continuity along the ground side. There are grounds from the battery to the block. another 2ndary ground for the EEC that goes to the post behind the battery on the firewall and to the neg battery terminal, another ground for the HEGO orange wire to the firewall, another ground wire from the firewall to the cylinder head or block behind the driver side, and if you have a 3g alternator there should be another ground cable from the block to the driver or passenger side frame or inner fender. All of these connections need to be tight, clean, shiny and free from dirt, grease, etc.
 
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What these guys said. I would also bypass the msd if possible or go back with the stock set up for the time being until you get everything sorted out. MSD stands for My Spark Disappeared.
 
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Thanks for all the advice guys sorry for not responding sooner but with everyone's help we finally found the problem and now the car is running great..for a little bit, we ran into another problem that has left us stumped...that car runs great for about 10 minutes and then it loses power and has trouble staying running, the oil pressure also drops from 60 psi to 40 psi so idk if that has anything to do with it but if y'all have any ideas please lemme know!