slow cranking issue
Thread Starter
Teching In
Joined: Oct 2021
Posts: 12
Likes: 2
slow cranking issue My LM7 swap started cranking slow and I'm having a hard time figuring it out.
This is a new swap thats not finished but close, i started it for the first time last month and the starter spun fast, now it acts like the battery is dead when i turn the key, but....if i hold the key in the start position the motor starts to spin a little faster, then faster, then it starts...
i removed the negative cable from the block and cleaned the ground, then the grounds for the harnes i did the same and neither had an effect on the slow cranking.
The starter is new for this build and i dont want to just throw parts at it and spend needless money but am at a loss on what else to check?
This is a new swap thats not finished but close, i started it for the first time last month and the starter spun fast, now it acts like the battery is dead when i turn the key, but....if i hold the key in the start position the motor starts to spin a little faster, then faster, then it starts...
i removed the negative cable from the block and cleaned the ground, then the grounds for the harnes i did the same and neither had an effect on the slow cranking.
The starter is new for this build and i dont want to just throw parts at it and spend needless money but am at a loss on what else to check?
Triple check major electrical connections between battery, starter, alternator, and fuse/relay panel. Likely a loose/corroded power or ground cable (also verify crimps/solders are solid without corrosion). Slow turning starter is almost always lacking power supply until the starter itself is going bad.
Trigger wire (purple) isn't going to be the issue, that one just triggers the starter solenoid. Sometimes the starter needs a little tough love (hammer tap) but that doesn't sound like the case here.
What kind of battery are you using? Are you 100% sure it is charged to 100% with enough reserve capacity and pass load test? From experience, auto parts stores don't always check batteries the right way (load test).
Trigger wire (purple) isn't going to be the issue, that one just triggers the starter solenoid. Sometimes the starter needs a little tough love (hammer tap) but that doesn't sound like the case here.
What kind of battery are you using? Are you 100% sure it is charged to 100% with enough reserve capacity and pass load test? From experience, auto parts stores don't always check batteries the right way (load test).
Thread Starter
Teching In
Joined: Oct 2021
Posts: 12
Likes: 2
let me add a bit more info..... i did check battery and it tested good,
i checked power at positive terminal of batt and then at starter when cranking and it was good ( voltage drop was 2 volts to 10 volts while cranking)
i did have an issue after first starting where i had 2 dead cylinders and had to remove my wire harness and fix power supply to two cylinders....when i did this i had to remove the starter, amd when i reinstalled the wire harness i moved the ground wires from back of the head to back/top of block....seems like after that is when the issue started but i don't see where it could be going wrong, the other night i removed the harness grounds, cleaned everything, made sure there was no paint in the way and reinstalled with out and change to cranking.......i just installed the original tune i used to start the engine.....thinking it may have had to much timing but that didnt help eitehr
i checked power at positive terminal of batt and then at starter when cranking and it was good ( voltage drop was 2 volts to 10 volts while cranking)
i did have an issue after first starting where i had 2 dead cylinders and had to remove my wire harness and fix power supply to two cylinders....when i did this i had to remove the starter, amd when i reinstalled the wire harness i moved the ground wires from back of the head to back/top of block....seems like after that is when the issue started but i don't see where it could be going wrong, the other night i removed the harness grounds, cleaned everything, made sure there was no paint in the way and reinstalled with out and change to cranking.......i just installed the original tune i used to start the engine.....thinking it may have had to much timing but that didnt help eitehr
