03DelcoRemy Diagnostic Manual130004222020

delcoremy.com Page 13 Slow or sluggish cranking may be caused by high resistance in the battery cables or connections, especially in cold weather. After all batteries test well and the terminals are clean, check the battery cables. This involves placing an adjustable carbon pile load on the batteries at the starter and then measuring the voltage drop in each cable. The voltage drop in the positive cable plus the voltage drop in the negative cable equals the total drop or the difference between the battery voltage and the starter voltage. 3-8. TEST PROCEDURE. NOTE For a 24-volt system, use a 24-volt carbon pile. As an alternative, connect only one 12-volt battery to the system (disconnect all other batteries). Test at 12-volts but use the amperage specified for a 24-volt system. Immediately upon completion of tests, reconnect batteries in the approved manner for a 24-volt system. Connect CAUTION Starter solenoid BAT terminal is at battery voltage when batteries are connected. 1. Positive carbon pile lead to starter solenoid BAT terminal. 2. Negative carbon pile lead to starter ground terminal. 3. Battery cables (see NOTICE above) if not already connected. NOTE At starter, make voltmeter connection to terminal—not to carbon pile clamp. 4. Low scale digital voltmeter from starter solenoid BAT terminal to battery positive. Test 1. Turn on carbon pile and adjust load to 500 amps (250 amps for 24-volt system). 2. Read and record positive cable voltage drop (V4), then turn off carbon pile. Connect NOTE At starter, make voltmeter connection to terminal—not to carbon pile clamp. 1. Low scale digital voltmeter from starter ground terminal to battery negative. Test 1. Turn on carbon pile and adjust load to 500 amps (250 amps for 24-volt system). 2. Read and record negative cable voltage drop, (V5) then turn off carbon pile. 3. Add positive cable loss (V4) and negative cable loss (V5) to get total cable loss (V3). This loss (V3) shall not exceed: • 12-volt system with 37MT, 40MT, 41MT or 42MT starter — 0.500 volt maximum voltage loss • 12-volt system with 50MT starter — 0.400 volt maximum loss • 24-volt system with 37MT, 40MT, 41MT, 42 MT, or 50 MT starter — 1.000 volt 4. Replace cables or repair circuits with excessive voltage drop. 3-9. TEST COMPLETION. If temporary 12-volt test connections were made for 24-volt systems, reconnect batteries to vehicle specifications for 24-volt operation before starting vehicle. However, if the tests following are to be performed, keep the temporary 12-volt hook-up. FIGURE 3-3. Battery Cable Test – Typical 12-Volt System