SOLVED - '91 won't start - click click click
 

SOLVED - The FM turbo heat shield was removed 6 weeks ago. One of the bolts was the bolt that normally connects the ground to the chassis (braided line). I AM DUMB (but figured it out). I bought a new battery that wasn't needed and a starter that wasn't needed but it probably didn't hurt to replace them.

I bought a 91 turbo with voodoo box six weeks ago and drove it three hours home. It had not been started in two years. The guy put a lawnmower battery in it. Got it home and started tearing it apart. Things of note: Pulled the ECU/voodoo box, installed a relay by the battery for ACC power, disconnected CAS and coil to change valve cover gasket and CAS o-ring. Went to start it up after sitting for six weeks and it would either give me click, click, click or just barely turn over (guessing one rotation). I used my truck and jumper cables - same thing. Bought a new battery - same thing. Turned the engine over by hand - felt ok. Put a remanufactured starter in - click click click. I hooked a meter to the big starter wire and engine block and power dropped to +3.7V when trying to start. Any ideas? I'm thinking the 3.7V is indicating a poor connection to the battery but I'm so pissed/tired/stressed right now that I only want to grab a beer and look at it again tomorrow.

You shouldn’t drop below 9ish volts while cranking. Try pulling the plugs. Your battery and starter need to be able to turn it over without plugs. If not, the reman starter is bad (likely), AND you’ve been missing an important ground, either by the back of the ppf, trunk by the battery, or by the firewall, exhaust side.

edit: oh I see I was right, missed the big SOLVED part.

Thanks anyway! Hopefully someone will find my post when they are pulling their hair out trying to figure out their problem.