Posted: Mon Feb 20, 2017 10:58 am Post subject: Ran then wont start?
My friend has a 47' willys and was running nicely, he stopped in the pasture and cut off to do some work. Then got in and all it does is "click" one time and starter doesnt turn. i am going over there after work which will be blind leading the blind!!!! any advice on where or what to do? thanks for any help _________________ 1952 M38
Start with determining and sharing with us if the jeep is stock. If it is not then let us know what systems have been modified to what level. IE: engine is stock L134, electrical is stock 6 Volt and is the starter and it's starting switch stock 6 Volt remote switch.
It is always best to show up at an electrical problem with a decent digital VOM. This will save you many wasted hours.
The very 1st question that needs to be answered is: Do we have the same system voltage at the battery plus terminal that we have at the starter plus terminal both before and during a start attempt? The answer to this question will tell you where to look. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Battery Plus post read 12.8 volts. Cable attached to solenoid to stater read 4.67 when key was turned. Jeep had been rewired or jimmyrigged for a key . When turn key , you would hear one click. I put jeep in 1st and pulled it off which it cranked right up. _________________ 1952 M38
Do we have the same system voltage at the battery plus terminal that we have at the starter plus terminal both before and during a start attempt?
Quote:
Battery Plus post read 12.8 volts. What did it read while the key was in start? Cable attached to solenoid to stater read 4.67 when key was turned.What did it read before the key was turned to start?
As I said in my first post, I need two complete set of voltage readings to decide the source of the problem.
Also since you say it has been modified to 12V and they have added a solenoid to the start circuit we need 8 readings. It is best to fasten the ground lead of the meter to one ground and use the same ground for every reading.
TEST ONE With key OFF: Battery & battery side of solenoid, Starter side of solenoid, and starter positive post.
TEST TWO With key in start position: Battery & battery side of solenoid, Starter side of solenoid, and starter positive post.
What you are looking for is a significant voltage drop between any two points in the system. For example 0.2 voltage drop across the first two steps with key off points to loose or corroded terminals on either the battery or the solenoid. 0.3 drop on the starter side of the solenoid on the first test would indicate only a drop of one tenth across the solenoid itself which is acceptable since we had a 0.2 drop on the other side.
The easiest way to do this is use a tablet and record each test result first. Then analyse the results.
Test One:
Bat = 12.8
Sol A = 12.8
Sol B = 12.7
Start = 12.7
This would be acceptable.
Test Two:
Bat = 11.6
Sol A = 11.6
Sol B = 10.4
Start = 10.4
This would be unacceptable because it indicates very high resistance or voltage drop across the solenoid itself. In this case it would indicate the need for a new solenoid.
Note that in test two the battery voltage will always drop. This is normal during cranking but should NOT drop below 11.2 on a fully charged 12V battery (fully charged will read above 12.5).
Now if you happen to get a Test Two results that look like these:
Test Two:
Bat = 12.3
Sol A = 12.3
Sol B = 12.2
Start = 12.2
And still only get a single click and no rotation of the starter then you need to look at the starter itself. Don't jump to conclusions though. Check the simple things first. IE is terminal nut tight? Is termal connection clean? Are starter mount bolts tight??? _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
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