Hello,
My Dad's car wouldn't start and so he asked a family friend to have a look at it - he advised that the starting motor could be the cause of the problem so my Dad has replaced it. It still doesn't start - nothing happens when the key is turned except the first time after the motor was replaced, there was a click. That's it.
We did notice the old motor had 10-teeth compared to the 9-teeth on the new one but we spoke to Bosch who advised this should be ok.
We have very few symptoms to work with so I was lookign for some advice about diagnosis of the issue.
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Connect a wire to the battery + connection and just touch it on the small terminal of the starter, if it now turns you either have a faulty ignition switch or the wiring associated with it. If it doesn't turn, either you have another faulty starter or there is no 12v supply on it or no earth.
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Is the battery fully charged?Just because the dash lights up does not mean there is enough power to spin a sterter.Get an auto electrician to come and test it,the starter and associated circuit before wasting any more money,diagnosis by replacement is an expensive way of finding faults.
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I doubt if you can casually swap a 9 tooth dog for a 10 tooth and still expect proper engagement. Get the circuits checked first.
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If you are wanting to check the circuits your self. This should help. start by measuring the battery voltage,
13v to 14.5v is good. Anything less indicates battery needs charging or replaced. If ok clean battery terminals + and - and also the connections. While the battery is disconected clean all connections on the starter motor and also the connecting wires. use a highly abrasive paper. Also follow the earth terminal from the battery and clean the connections. There is also normally a large earth cable which joins the engine to the main car structure. normally around the clutch housing area..These are sometimes a cause of problems of this nature, They are exposed to weather elements and can start to corrode and even break up, Make sure this cable is sound and doesnt fall apart under strain. Make sure you give the connections a good clean. You could also check the voltage to the starter which should be the same at the battery. A quick way to check for an earth fault is to connect a jump lead to the battery NEGATIVE - and the other end to a good EARTH piont on the engine i.e a large nut or bolt and try to start car while this is in place. Hope this helps.
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A fully charged 12v car battery will only ever show a maximum of 12.7v whilst at rest and around 12.06v at 50% capacity.
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It's certainly a good policy to ensure that starter connections are clean and tight but don't attack them with abrasives. Terminal lugs are usually made of brass or copper, plated with nickel or tin in order to inhibit corrosion. Lugs adjacent to a battery should always be lead plated.
The removal of any plating on terminals with abrasives will cause incurable corrosion later on. Clean the lugs with rag and a solvent and ensure that in the case of an earth, the bodywork is clean (an abrasive might be needed here), then coat terminal joints liberally with vaseline - which is acid proof. Do not use grease. Joints on the starter which get hot can be smeared with silicone grease - vaseline will run off engine mounted components.
On the Passat, the earth lead from the engine to the body is accessible at the front offside after removal of the undertray. The battery earth to the body is in the plenum chamber and is prone to corrosion at the bottom.
It is relatively commonplace to cut a 9 tooth pinion on a 10 tooth blank in order to optimise starter ratios. Sometimes the ratio will change if a replacement motor has different characteristics but it is always important to fit the correct replacement otherwise expensive damage can be caused to the ring gear.
Ignition switches are not above reproach on the Passat. Remove the solenoid feed wire (terminal 50) at the starter and connect to it a 12V 21W lamp - other side to earth. Check that the lamp illuminates to full brightness when the key switch is operated to the start position for at least 10 times.
If this test is passed and all of the heavy connections are in good order, the starter needs to be removed for checking.
659.
Edited by 659FBE on 21/05/2009 at 00:00
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A fully charged 12v car battery will only ever show a maximum of 12.7v whilst at rest and around 12.06v at 50% capacity.
A battery can show full voltage and not have the power to turn a starter,a no load test on a circuit means nothing,especially with a digital meter.As the OP asked someone else to look at it,who had a guess at the starter motor,I doubt they have the technical competence(no offence) or equipment to be testing voltage drops etc..Hence the suggestion to get someone in who knows what they are doing.
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