The engine will not turn over after a call for start, the classic no crank condition.

The possibilities are:

Improperly charged battery
Weak battery
Corroded or damaged connectors/cables
The high power voltage at the starter from the battery
The energizing voltage at the starter pull in coil
The ignition switch voltage to the coil of the starter relay for the starter pull in coil power
The starter alignment to the flywheel
The starter

Start by looking at the cables and connections looking for loose, corroded, frayed or shorted connectors or cables.

Then check the resting battery voltage. A fully charged battery reads around 12.6V. During cranking your battery voltage should stay above 10.5V at the battery unless its really cold outside. If you suspect a weak battery you can have it load tested. It gets a proper charge, the surface charge is bled off and then the voltage is tested under a calibrated high current load with a carbon pile or wire wound resistor.

Next is how much voltage drop are you getting from the battery positive to the heavy power cable connection at the starter during a cranking attempt. This should not be more than a few tenths of a volt drop or there is a cable or connection problem. This is usually a large black or red cable. Same is true for the voltage difference between the starter case and battery ground. The current draw from the starter should be 90-140A steady state which you can check with a clamp meter.

Next up is the power control signal to energize the starter pull in coil. The path is usually:

Battery>battery fuse> Ign A fuse>starter relay contacts>purple wire to starter pull in coil

If there is no 12V power, or the voltage is low at the purple wire at the starter then you can work backwards to find the problem. If there is 12V going into the relay contacts then its either the relay or the relay control signal. You can swap with a known good relay to rule out that possibility if your at this point.

The relay control path is usually:

Battery>Ign C fuse>ignition switch>crank fuse>clutch pedal switch or park neutral switch>starter relay coil>gnd

If there is voltage into the relay contacts but no relay coil control voltage during a call for start then you work your way backwards from the relay coil to the battery until you find the problem.

Here is a typical starter circuit diagram:



Some articles that might help:

https://blazerforum.com/forum/2nd-ge...59/#post732668

https://blazerforum.com/forum/2nd-ge...29/#post731395


The starter gear should fully engage with the flywheel teeth with 20-60 thou clearance between the peaks of the starter gear teeth and valleys of the flywheel teeth. Use a wire to check the fit and use shims to adjust. If there is no inspection plate then you have to mark the gears and check the fit after a few start attempts.

If everything is good to this point then you can pull the starter and have it tested.


George