I have a 1975 grand lemans. Just did an engine swap from a 4.1 250 to a 1974 6.6l 400 bb. Question: the 400 ran before we put it in. Now it won't even turnover. Power to everything, won't crank.

Asked by Aug 12, 2014 at 11:53 AM about the 1975 Pontiac Le Mans

Question type: General

8 Answers

104,285

Can you turn the engine with a breakover bar and socket on the big bolt that holds the vibration damper on? What transmission did you put in it?

Yes. We can turn the engine as much as we want. And the transmission is the mated TH400 from the donor car.

104,285

If the starter doesn't make any noise like a clank or a hum then you are missing a circuit.

missing a circuit? where? we've tried tracing wires and they all seem in order.

104,285

Most likely the key power to solenoid circuit, do you have a three wire solenoid or just a two? If yo have the three try switching the two small wires you could have them switched.

two wire solenoid. three wires going to it.

104,285

One large battery cable, and the 2 other smaller wire connections on either side and down just a little from the main post. Get a test light and have some hold the key in the crank position while you test to see witch one of the small wires are hot then have then release the key and the light should turn off, that wire should be on the left side of the main terminal, if it is and it still won't crank the starter could have went bad by just sitting, try lightly tapping the starter with a hammer while someone holds the key in the crank position, if it then cranks your starter is on it's way out, if it doesn't crank or starts smoking it is a bad starter.

Awesome thank you! will definetly try it later.

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