need help removing the starter

trying to remove teh starter solenoid from my car.. thinking.. hopeing its the problem i have.. i jus had a new engine put into my car.. but however maybe a day or so after everything was completed.. after my car was running and all with the new engine in it.. i had problems with my power supply.. i will try and explain the best i can.. when i turn the key in the ignition i get no response. no click noise from the stater no lights no nothing... but however when i have somebdy jump me once the battery cables .. my car starts up fine runs great.. but once i shut my car off.. im back to geting nothing.. so once its off it stays off.. untill i get another person to jump me.. ive asked around an people have been telling me to start with the solenoid.. i guess my little problem is that the location of the starter is in a bad place.. i jus have no room to do anything.. if anyb dy has any experience installing and removeing starters on mustangs.. any advise would be truley greatful.. thank youi

Welcome to AF!

It sounds like the battery is discharged or the terminals on the battery are dirty or loose. Check the voltage with a DVOM. It should be 12.6 volts or more. If the battery is fully charged and the connections are tight and clean, then you may have a bad ground cable. Measure the resistance from the negative battery post to the engine block. There should be little or no resistance. If the resistance is more than that you need to clean the negative ground cable.

If you want to change the starter you will need a ratchet with an extension to get the top starter bolt. The bottom bolts are easy to get to. Before pulling the starter disconnect the negative ground cable from the battery.

I'd suspect a weak alternator or a wiring problem preventing the battery from charging. Frayed wires or lose connections can cause this. You can also take your car to an auto parts store where they can test the alternator and battery in your car. It might help identify the problem.

It always helps to give the year, and a lot of times what engine you got. A lot of times the terms solenoid and relay are interchanged.

It's not the solenoid on top of your starter, beings it starts with a jump. It wouldn't be the relay either. I would start by making sure you have a good and also well charged battery, and the battery cables are in good condition and clean and tight.

Look and if you spilled anti freeze on the ground or positive connections clean with contact cleaner.