2000 isuzu trooper no start with slow crank loose 4 volts at starter
automatic or stick>?no engine size stated. gas or diesel.slow crank, 250 -300 rpm is normal.so did you AAA tow truck style , jumper cable crank that car off a running donor car yet>? just that act (test) speaks volume for cause.what does loose 4v mean...??10-11v is normal voltage at starter. cranked.4 v at the solenoid can not even begin to close it,or did you mean the 12vdc is 4v lower that 12vd. which is 8v.perplexing. (3 cheers 1st poster here with voltmeter, im am truly shocked,(no pun) honest reply.......!!A fuses blown. (DEAD CRANKS)DEAD BATTERYBATTERY BADbATTERY JUST DISCHARGEd.wrong sized battery in car, (tiny)LAST DRIVE? the charge system died, and now battery is weak. fix charging system.left head lights on, cure , charge battery.battery terminals rusty !( yes they have 4 ends they can rust or get loose) 500 amps here so must be clean and tight.(bat terms)jumper cables jump starts car ok?, yes, then battery dead.battery bad, battery only discharged ?next:jumper cables don't crank fast, then hot wire the starter. (big wire to tiny) more testing....with known good charged battery (12.6vdc rested)i hot wire the starter solenoid.i monitor the voltage at starter actual.with a volt meter.most cars do 11v, in warm summer.if much less, say below 10v the starter will be slow. so i monitor battery terminals volts.and if ok, there, the cables are bad. (voltage drop on cables is that, yes, cables do fail.)or the starter is partially shorted. or engine seizing....hand turn engine crankpulley and feel it.? feel normal, ? or cant move it...?if i suspect a bad starter i use my ammeter.the starter current will be about 200 amps .no engine stated so.....i guess....if it goes to like 600+, the starter is shorted.I have an amp clamp amp meter, that allows me to see and find the hard cases...