Hard to start when engine is warm

[BobWolterbeek]

My lights were dim, the red dash light came on if I had the lights and the winshield wipers on. Then the starter motor acted like I had a dead battery (even though I didn't). I replaced the alternator and the starter motor. Didn't help. I replaced the wire from the alternator to the starter motor with a 6 guage wire. This fixed the dim lights and the red worning light on the dash. But, I still have the problem with the started motor acting like I have a (almost) dead battery when I try to start the engine when it's warm. Any ideas? I thought about running a separate ground wire from the battery to the starter.

[courtenay]

Check this link - might be part of the problem
viewtopic.php?f=6&t=8321&st=0&sk=t&sd=a&start=15#p76617

[divace73]

Hi Bob
You most probably have high resistance in your ignition switch. All the power runs through the ignition switch. I get that when the car gets hot (i still havent repaired/replaced mine)
Try and swap your ignition switch with another to see if this is the case, or if you have the time carfully pull it apart clean it and put it together try this link http://www.mirafiori.com/~kdickson/switch/switch.html
Hope this helps

[RoyBatty]

Check the main ground under the car where it hooks the body to the transmission bell housing.
I recently installed a replacement transmission and forgot to connect this ground.
The starter would turn the engine over. But is sounded like I had a weak battery or bad starter.
I remembered the ground and reconnected it.
BAM! Problem solved.

[BobWolterbeek]

Thanks guys, I'll first check the ground and if that isn't it I'll go after the switch and if that doesn't work I'll be back begging for help. Bob

[majicwrench]

Is not likely the switch. Not all the current runs thru switch. Very little does. The current to run the starter comes thru the positive battery cable, and the big strap at the bellhousing provides the ground path.
What voltage does battery read at rest?? with engine running??
Keith

[So Cal Mark]

as Keith suggested, a voltmeter is required unless you just want to guess. My bet is the starter draw is high when it's hot. But, you need to check for a voltage drop between the battery and starter and ground. Also, check voltage from the switch to the solenoid when the problem occurs

[divace73]

I should correct myself, not 'all' the power runs through the ignition switch but the 12v to the solenoid does. From my experience, I tested what should have been approx 12v at the switch ended up being 8 volts of so, I now know why my dash lights are so dim, they were nowhere near 12v, I get voltage drop all along different parts of the circuit. Previous to my ownership somebody had rewired the head light power through relays as well.
Just saying that it is somewhat common for older Italian ignition switches to play up after 30 odd years of use.IMO
Any yes ensure all earthing point are clean and connected properly.

[parsok]

Myself and another are having the same problem. Did this get resolved and if so what was the solution?