Solenoid/starter problem

[aguiarj]

Hi everyone,

I have been driving my 80 Spider most of the summer and enjoying it. Last 2-3 weeks though, I've experienced some probelms getting the car started.

I think I have a problem with the starter, but want to rule out that the solenoid is problematic. When I turn the key sometimes is goes real well and fires up right away, other times, it chugs like it was cranking a truck engine

I have some instructions for testing the starter. Any suggestions on how to test the solenoid? Could it be the solenoid needs replacement alone or should I simply change out the whole thing, ie starter/solenoid?

any feedback is appreciated.

Thanks,
John

[So Cal Mark]

if the starter is dragging (especially when hot), it's not a solenoid issue. Time to replace or rebuild the starter

[mbouse]

agreed. the solenoid should be almost an on/off, yes/no decision. if your starter is engaging, the solenoid is doing its job.

since there will be future need, go ahead and get friendly with your local starter/alternator rebuild shop, and hand him your starter. He'll letcha know if it is worth rebuilding.

if i hadda choice of new or rebuilt, i'd grab one of those new, lighter gear reduction starters.

[spider2081]

It is possible to have a bad solenoid that causes a starter to turn slow. The solenoid contains the contacts that supply current to the starter motor. If these contacts get pitted and warn there can be an excessive voltage drop across the solenoid. A meaningful test for the starter/solenoid is to check for a voltage drop across the large posts of the solenoid. As Mike states the contacts should be open or closed. When the starter is cranking Idealy there is no measurable voltage bewteen the two large posts on the solenoid. IF there is the internal contacts are dirty or pitted. Also measure the battery post of the solenoid to ground when cranking. If the voltage drops more than one and a half volts check all the coneections from the battery positive terminal to the starter. Also check the ground at the battery and the engine ground at bellhousing to the car's body. You might also want to check the voltage drop across the batteries posts while the engine is cranking. If the battery is healthy and fully charged the voltage should not decrease more than one and one half volts while cranking from not cranking.