Help! Starting problem

Hi All

New member. Got a slight problem with my Mk1 conv' GTI 1.8

Voltage reading 12 before start up, but on turning the ingnition the power drains and the starter motor turns lazlily, and usually won't start. When turning ignition back off the voltage reading kicks back up to 12 again. Was happening every now and then but has been constant for the past few weeks.

Already replaced the battery and alternator a couple of times. the alternator bushes seem to be warn very badly on one of the alternators i've changed, everytime I change the battery or alternator the problem seems to go away and then comes back again.

Please, please help if you've got any ideas - thanks

What's the voltage across the battery during the starter spinning?

About 8v if i jump it it'll start and then it'll start on command easly it only seems to be when its been left for awhile. Like over night.

cheers for the responce

Duff battery.....

Also, it could be something consuming the current overnight, for example, alarm/immobiliser, radio memory, courtesy light stuck on, etc. But since the Mk1 Golf electrics are relatively simple, this is unlikely. You could test if its this, by removing the earth terminal and using the multimeter to measure the current drawn (make sure the door is closed, so courtesy light is off). Or, take the battery off and leave it overnight, then reconnect and try to start it.

OKAY - GET READY - BIT LONG WINDED!!!

Battery does seem to be the obvious I agree.

It's just puzzling that I've changed it so many times it works for a while (couple of months) then goes funny again. Someone suggested it was the alternator (thus regularly causing duff batteries) but even that I've replaced a couple of times - again works for a while and back to square one - I have been getting them from one supplier though - maybe they are all poor quality?

When I do get it started, if I turn it off it will then start again perfectly, but not if I leave it. Sometimes it will turnover and start straight away, sometimes it sounds like lazy starter motor sydrome but then all of a sudden speeds up and starts (when it does this it always re-sets the MLF thingy) and sometimes turnsover V.slowly and eventually gives up, yet still shows 12v

One of those typical inconsitent annoying problems! Thanks for all your comments I am so greatful for all your suggetsions!  

Cheers

It coule be a weak alternator, not charging the battery, thus flattening them, which shortens their life. You can test this, ideally by putting an ammeter in series, but nobody does this these days. Instead, you could use your voltmeter to see the voltages after startup and over a 5-10 minute period once started. Then, switch things on and see the effect on the battery voltage.

It might also be worth replacing the earth strap (to the engine) and obviously worth checking the electrical connections to the starter.

Once you are confident that the battery (and alternator) are okay, then you need to 'catch' the car in its fault condition and do some tests. Its possible that you have a 'tempramental' starter motor, too.

cheers paul i'll give it all a try and see what i come up with

my 1.3 is doing exactly this, its driving me MAD !!  

Its a daily driver too, so its infuriating.

Going to check ignition switch, starter motor wiring etc..

If i can be bothered at the weekend, im going to pull the starter and put 12v across it directly on the bench, then check all the voltages at the starter motor end of the wiring.

Also, is there a bush in the gearbox that the starter motor drive sits in ? could this be worn ?

could be the earth strap from the battery to the engine/chassis.

Gold mk1- Yeh there is a bush on the starter drive end, but it refused to come out on mine!  So its still there with the new motor! :roll:    

I reckon its a sticking starter Em but take others advice first and check all the voltages

Arun