question Ferret Starting Issue

[fv1609]

If you want to rule out problems associated with the starter motor, then there is always the starting handle

[griff66]

eat spinach first !

[rob233]

HI all, i have just spent the winter rebulding my mk1, when the engine was on the floor i had it running for a few mins,to check everthing was ok, put the engine in. And carried on with the rebuild when it came to starting the engine when almost

finished,the engine would only run when cranking,on checking i lost 24v at the distributor, the problem was a bad

connection at the round multi plug under the ignition switch panel.

It took me a long time to find but a few seconds to fix, i can not remember the wires concerned but if you look at a wiring

diagram you should be able to work it out.

 

Hope this helps ROB.

[joeferret]

This thread is a wealth of information...Thanks to all...

[01ec28]

just a mention that if you dont trust v reading remember that the meter can be placed in series and ma or amps can be monitored. this can help ferret out high resistance connections.suggest jumpering out straight from batt to coil to testrunning of motor. then as mentioned hunt for conn prob.remember there is also a conn strip next to breaker box in cab.take note that at least one set 9is internally jumpered ign if memory servs

[Diana and Jackie]

Sorry, totally disagree.

 

To find a high resistance series connection the circuit should be energised and the place where the voltages changes i.e where the volts drop occurs, is the place where the high resistance joint occurs. Not forgetting that the meter resistance will have an affect, particularly on low current circuits.

 

One cannot find a high resistance connection using an ammeter, excepting to determine that particular circuit is not operating correctly (has a high resistance series connection), unless of course one pokes about and disturbs connections, which is not recommended as there maybe multiple connections at one point, or the fault maybe intermittent such as a dry joint, especially on PCB's. Far better to find the fault and deal with it.

 

 

The other good reason is an AVO (or some versions) have a mechanical cutout, Digital meters have (often but not always) a special high speed fuse. If a connection error occurs then the possibility exists to damage/destroy the meter or destroy the fuse (which is a pain in the bum to find a replacement for).

 

The alternative method is to use an ohmmeter or Wheatstone bridge however where there are small high resistance series joint. (and there is always some resistance in a circuit and even meter leads) the determination of the relevant actual amount affecting the circuit in question is often quite difficult, especially when high currents are involved.

 

Meters should ALWAYS be stored switched to the highest possibly AC voltage, that way when you go to use them if you forget to change ranges there is less likelihood they will be damaged.

 

Of course if the circuit fuse pops perpetually then use and ohmmeter to go through the circuit to find the shunt low resistance or short circuit

 

Diana

 

 

 

 

 

just a mention that if you dont trust v reading remember that the meter can be placed in series and ma or amps can be monitored. this can help ferret out high resistance connections.suggest jumpering out straight from batt to coil to testrunning of motor. then as mentioned hunt for conn prob.remember there is also a conn strip next to breaker box in cab.take note that at least one set 9is internally jumpered ign if memory servs

[griff66]

hit it with a hammer go on!!!!!!

[01ec28]

Sorry, totally disagree.

 

To find a high resistance series connection the circuit should be energised and the place where the voltages changes i.e where the volts drop occurs, is the place where the high resistance joint occurs. Not forgetting that the meter resistance will have an affect, particularly on low current circuits.

 

One cannot find a high resistance connection using an ammeter, excepting to determine that particular circuit is not operating correctly (has a high resistance series connection), unless of course one pokes about and disturbs connections, which is not recommended as there maybe multiple connections at one point, or the fault maybe intermittent such as a dry joint, especially on PCB's. Far better to find the fault and deal with it.

 

 

The other good reason is an AVO (or some versions) have a mechanical cutout, Digital meters have (often but not always) a special high speed fuse. If a connection error occurs then the possibility exists to damage/destroy the meter or destroy the fuse (which is a pain in the bum to find a replacement for).

 

The alternative method is to use an ohmmeter or Wheatstone bridge however where there are small high resistance series joint. (and there is always some resistance in a circuit and even meter leads) the determination of the relevant actual amount affecting the circuit in question is often quite difficult, especially when high currents are involved.

 

Meters should ALWAYS be stored switched to the highest possibly AC voltage, that way when you go to use them if you forget to change ranges there is less likelihood they will be damaged.

 

Of course if the circuit fuse pops perpetually then use and ohmmeter to go through the circuit to find the shunt low resistance or short circuit

 

Diana

 

well of course the circuit needs to be energized. this applies to volts or amps! The meter uses a shunt and to have an affect youd need to be looking at milli or microohms and that wasn't the issue here. Unless I misunderstood the poster, he had a concern that the voltage reading he was seeing was not true or accurate. remembering that voltage taken with a quality meter (near infinite resistance as in an oscilliscope) can mislead if there is carbon tracking or some other form of resistance in the circuit. Using amperage to see what is there or in this case not there, would have eliminated his doubt as to wether he had a high resistance circuit. Using amps is for process of elimination, obviously it wont point you to the problems location but it will tell you the degree of your issue.

 

digital meters blowing up? In my profession we would coordinate fusing with a fused jumper(banana plugs do fit in fluke meters and likely many others you may use). You make sure this fuse is well under the 10A fuse of your meter and your fine. No need to blow the fuse in your digital meter, that ones for mistakes, not intentional circuit monitoring. if one is still determined to blow up a meter, it likely is not a very good meter and perhaps we are talking about two very different worlds of test equipment and experience. There are low impedance ohm settings on digitals now. Meters need a high impedance for voltage, particularly on isolated dc power systems in industry as these will typically have ground detection, one partial ground on the system and a low impedance meter equals inadvertant relay or device operations that can be extremely damaging.

High currents? I dont suggest he use a 100a ductor on his wiring, he wasn't looking for microohms.

Just my one cents worth.