Punto Rescue

[DIYspanner]

2002 1.2 8V

Had to go up to Jesmond today and recover my nephew’s car.

12.4v with meter on battery but very slow cranking. Suspected a dodgy battery cell on cranking.

Managed to start using spare and jump leads.

Hell of a wine of the alternator.

Stopped the engine, fan belt off, alternator very stiff and notchy to turn by hand. Suspected a collapsed bearing.

Belt back on, jump started engine. Now a hell of wine off starter motor for a few seconds.

Left the engine to run and all strange noises disappeared – very strange!

Got the car driven back to home base in Co Durham.

Removed the starter motor. Pinion shaft coated in friction plate dust. The dust was causing the pinion to stick in and out, hence slow crank and not disengaging straight away when engine was started.

Cleaned off with petrol. Tested starter and good as new.

Took fan belt off and alternator rotated nice and smooth so obviously a bit of crap had found its way in but now clear.

Starter back on, battery and leads cleaned up. Engine cranked and started. No strange noises.

What an exciting day!

Just needs an oil/filter/spark plugs change. Might fix speeds 1 & 2 on the heater blower as well.

By the way, if anyone needs a good little multimeter, I recommend this one!

 

[Burnerman]

Interesting post!
The starter motor noise is the easy one.....so much crap on the pinion and shaft means it wasn't able to disengage. Although lubricant causes clutch dust to stick, Duck Oil spray is recommended here, once all things are clean.
As for the alternator, electrical drain makes the unit very hard to turn.....if there was a bearing problem I guess it would still be there
Your battery reading is very low, so I'd imagine Uncle Spanner is about to dig deep into his pocket?
John

 

[DIYspanner]

The battery is good. I measured the voltage without any engine cranking, IE no load on it.

When refitted after clean, the engine was cranking well on the starter.

I get what you mean about the alternator. Electrical drain causing magnetic fields, hence resistance - noted.

Thanks John.

 

[DIYspanner]

There's actually a direct battery to alternator cable connection.

Two cables on the starter motor pole, one to the battery, the other to the alternator.

First time I've seen this arrangement.

 

[Burnerman]

The alternator is always directly connected to the battery - this means that there is little chance of failure due to disconnection which will goose the alternator immediately......no switches, relays or whatever in the way.
I can't say I've seen such an arrangement as yours though - more often one lead straight to the starter and another to the alternator, straight from the battery positive.
John

 

[Avocet]

Obviously not the problem this time, but I had a nasty one on my daughter's 1.2 Punto ('56 plated 8 valve). It wouldn't start (no starter). I stuck a jump lead from the battery negative to the block and still no starter - so I changed the starter... Still nothing! it was only when I put the jump lead back on and then ran a SECOND jump lead from the battery negative to the BODY that it fired up.

The Punto has a battery negative cable that is one continuous length of copper from the battery negative to the gearbox. About 1/3 of the way along it, there is another connector crimped on - which goees to a stud on the chassis leg just under the battery. In this way, they can use one bit of heavy cable as both the body earth and the engine earth. Well it turned out that water had been running down inside the heat shrink round the second crimp under the battery. The cable LOOKED perfect but under the heat shrink, it was just green mush! Worth looking at on any Punto of around that age.

Also, the lid of the main fuse box runs close to the bonnet release cable and sometimes people don't secure it properly because it traps the cable under its lid. It then leaks and the bottoms of the fuse boxes on Puntos of that age are also prone to corrosion.

 

[DIYspanner]

Looking at the Punto starter motors on ebay, I noticed that they have a plastic shield that fits over the battery cable. Not present on the starter I did so called in at the local scrappy and got one. Really doesn't do much, just stops dirt ingress but best to have the job right.



Got the heater working I mentioned above. Link between terminal 2 and 3 on the resistor unit was broken. Terminal 4 is directly connected to the blower motor, the three other terminals via resistors.

The easy way to test the resistor unit, first disconnecting the battery for safety, is remove the unit and connect you ohm meter to terminal 4 and the other terminals to see if there's a resistance. If its open circuit, the fan motor is no go on that speed.

 

[Burnerman]

A useful post!
Keep an eye on the head gasket though the early Punto's were terrible for popping these - hopefully they are a bit better now.
John