robp823 Posted June 19, 2009 Share Posted June 19, 2009 I have a 96 f-250 come in today that doesnt crank long at all.The customer said he put 2 new batteries in it but it didnt help. You can crank this thing for literally 5 seconds and the batteries just drain and barely cranks.Now while playing with it the starter acted up and i had to hit it with the old hammer and it started cranking again. Could a bad starter be taking that much of a draw???? Quote Link to comment Share on other sites More sharing options...
Aaron Posted June 19, 2009 Share Posted June 19, 2009 Probably needs a starter. How many amps does it draw? My guess would be a lot. Quote Link to comment Share on other sites More sharing options...
robp823 Posted June 19, 2009 Author Share Posted June 19, 2009 im gonna throw a starter in it tommarow see what happens Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted June 19, 2009 Share Posted June 19, 2009 Instead of throwing a starter at it, why don't you spend 5 minutes doing diagnostics, like an amperage draw test, voltage drop test, and maybe even a battery load test? "Customer said he put new batteries in". The correct CCA? Quality units, up on charge? With recent date codes on the cases? Not from AutoZone? These tests take less time than it takes to explain them when done properly. If you need help with a voltage drop test, say something, and we'll walk you through it. A VD test is very simple, takes less than 30 seconds and shows a bad cable or connection instantly. Yes, you're likely to need a starter, but more importantly you need to understand why it's important to diagnose the system and be able to point at a part and say, "It's defective". If you "throw parts" at problems, you're going to end up in a real fucking jam when you get a bad part or two in a row. You'll throw a LOT of parts once you get a couple of bad batteries/starters/cables/etc in a row. Maybe it'll take that before you learn something.... Quote Link to comment Share on other sites More sharing options...
robp823 Posted June 19, 2009 Author Share Posted June 19, 2009 Bruce the batteries are motorcraft and the correct CCA and recently purchased and i had a battery charger on them for a quite a while.As for the voltage drop test i basiclly want to take my multimeter hold both leads at each end of the cable and watch my drop correct? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted June 19, 2009 Share Posted June 19, 2009 Bruce the batteries are motorcraft and the correct CCA and recently purchased and i had a battery charger on them for a quite a while. Be careful- you can overcharge a new set of batteries and TRASH them inside of a few hours! As for the voltage drop test i basically want to take my multimeter hold both leads at each end of the cable and watch my drop correct? Yes, correct. To VD the positive side, put one DVOM lead on the positive POST (not the cable clamp!) and the other end on the starter STUD (not the cable eyelet!), set the meter on DCV, and have your buddy run the starter for 5 seconds. A really good one will measure .2v or less, .5v is the Ford spec. If it's above .5, take all of the connections apart and whizzer wheel them, and retest. Polarity on the meter doesn't really matter (red lead or black lead) but if it's backwards it will measure -.5v instead of .5v. To do the negative side it's just about identical- one lead on the negative POST, one lead on the aluminum starter case, and crank it 5 seconds. Getting on the battery post is a bit of a challenge itself- I know an old codger that drills a small hole in the lead post itself, puts a small self tapping screw into the top of the post, and uses that for his ground source. I've seen really weird fucking stuff that would blow your mind- alternators bolted tight that weren't grounded, starters bolted tight that weren't grounded, cables that looked LIKE NEW that had 3v of drop, BRAND NEW batteries that were fucking junk. 3 or 4 starters in a row from the parts store that were NFG. I'm old, (but not as old as Grampa) and I've seen it all. Getting your ass kicked really hard teaches you to do the diagnostics CORRECTLY. Don't shortcut! It takes less time in the long run and gives you a warm fuzzy when you can look the parts guy in the face and say, "That NEW part you gave me is NO F'ING GOOD", and be willing to bet money on it when you say it. Be the best at electrical problems, and everyone in the shop will admire you.... Quote Link to comment Share on other sites More sharing options...
robp823 Posted June 19, 2009 Author Share Posted June 19, 2009 why the post and stud and not the cable if im checking for a bad cable Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted June 19, 2009 Share Posted June 19, 2009 Because you want to include the complete circuit in your test. If you put your alligator clip on the cable eyelet (on the starter), you omit the connection between the cable eyelet and the starter stud itself. This is a very common source of problems- there may be several items stacked up on the starter stud, increasing the resistance even without corrosion, and giving corrosion many places to grow. I had a brand new F750/Cummins no-start in the driveway of my shop, blocking the doorway. This truck wasn't two months old! The truck happened to be the "ride back" for dropping off another truck for service. The shiny new starter stud had a shiny new cable and shiny new nut on it, but was not tightened properly at the factory (probably a union guy!). It arced between the cable, nut, and stud so badly the nut was welded in place on the stud and refused to budge. I had to whizzer wheel the nut in half and split it off the stud, run a die over the starter stud threads, and gasket whizzer the cable ends (there were several fusible link feeds present there, IIRC). A new nut and a blob of chassis grease to prevent corrosion, and he was on his way. One of the most important things to learn is to not trust your vision when testing connections- voltage drop is the only true test. Like I said, I've seen plenty of connections that looked spiffy with a wicked high voltage drop. You will, too, once you start doing VD's regularly. Good Luck! Quote Link to comment Share on other sites More sharing options...
Aaron Posted June 19, 2009 Share Posted June 19, 2009 A VD test is very simple, takes less than 30 seconds VD test? Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted June 19, 2009 Share Posted June 19, 2009 Quote Link to comment Share on other sites More sharing options...
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