Technical huge problem with many punto cars!

[chenrp]

hello,
in my country (ISRAEL) we have a great forum for the Fiat Punto.
but many cars. we have great knowledge but no answer to fix this problem.
so i am writing it to you, as our last resort.

car type:
Fiat Punto Spice: 1.2L 16V automatic gear cvt. stock(no changes.)
problem description:
1.the car stands in a "RED LIGHT" or in the parking lot, and the road lights turns on, when we turn the signal indicator or the hazard lights, the road lights become weak (every blink of the signal lights). same problem when the engine cooling fan starts to work.
2.slow reaction from the gas pedal. when the cars stand still, and you press the gas pedal aggressively (just for a sec), the RPM drops very low for a sec (half a sec) and only after that we get a reaction from the motor.
the RPM can drop so low, the motor can shut down from it.

i think that the two problems are related.

all the people that have this problem, changed the battery, checked the alternator, changed coils, spark plugs, spark leads, and cleaned the throttle body.
when the problem occurs there is a voltage drop (from a DVM check).

i think that there is a GROUND problem with the car.
can anyone help us fix this ones and for all...?

please help us.
thank you.

 

[Brendan W]

Sounds like a ground problem. The first thing I would do is open clean and grease all the earth cables from the battery to the gearbox , inner wing etc. Second check each cable terminal carefully at the connections to the earth points and the battery positive and negative. There can be a lot of corrosion in or near the terminals which goes unnoticed.

 

[chenrp]

that was my guess too.
where can i find the ground cable to the gearbox?
are there any pictures so i would clearly understand what to do?

thank you very much!

 

[Brendan W]

Manual transmission it's bolted to the top of the gearbox. Just follow all the cables from the battery ground post.

 

[chenrp]

thank you!
i will follow the cable, and return with answers tomorrow.

thanks!