I have 90 SI hatch with a bone stock 91 LS b18a1.

My problem is that when I manually start the car it wont start because every time the clutch is depress the voltage from the starter wire drops to 9.23 volts when cranking not enough to turn the motor over. But it puts out 11.97 volts without depressing the clutch.

I checked the input from the key side and output from the starter side and same thing cause I have a remote start thought it was the problem but ruled it out.

Constant, ignition, and accessories show 11.97 volts.

90% of the time if I remote start the car it works, 10% if manually starting it.

I checked all connections at the battery, ground connections where I can find it and used a wire brush on spots that's needed.

Checked for any loose connections.

I've had this for 2 years and nothing happen like this until a couple of week ago.

What can be causing this to happen?

Has anyone experience this before?

 

try a load test on the battery, I think auto parts places do this for free.

 

take the starter out and have it tested parts store do that for free. it could be your relay

 

You could always put a push-button start in. $10 worth of parts from the store, and about 20 minutes to install it. A few people have done it experiencing the same problems as you. It may not "fix" the actual problem but it starts the car.