Starter issue

[911buff]

Have a 71 with a no start issue.

To begin, when I twist the key the starter does nothing. There is a load on the system because the alternator light dims and I can hear the fuel pump slow. Trying the old cross the contacts on the starter method, it only sparks, will not turn over. Pulled the starter and the battery and both checked out good. Removed and cleaned every connection (except at the alternator). Checked continuity and voltage... all checks out. Still same result.

I removed the starter switch module because I read somewhere to clean it. I do not see how it can come apart. Not sure it is an issue.

Even inspected and cleaned the pin connector in the engine compartment.

What puzzles me is crossing the contacts on the starter/solenoid does nothing. But yet the starter checks out good.

Could the connection at the alternator be causing the issue? Any advice is greatly appreciated.

[dannobee]

Sounds like a weak or bad battery. What is the voltage across the terminals? And does that voltage drop when you try to start it? If the battery voltage is good and doesn't drop when you try to start it, there's a bad connection somewhere. Check for a voltage drop from the negative battery terminal to ground. If the battery voltage drops a bunch when you try to start it, the battery is suspect.

Can you jump start it?

[stlrj]

If you're a AAA member, they'll come out and jump it for you for free.

[911buff]

The battery and starter were pulled and I took them to O’Reilly’s and they both checked out as good. Even putting my battery charger to “start mode”, it does the same thing. Again the only connections that i did not take apart, clean and check for continuity were the the connections on the alternator (hoping to find another fault before I dig into the engine).

[dannobee]

That's a start. Before we dig into that, if you have a pair of jumper cables, hook one side up to the negative post on the battery and the other side to a convenient spot on the engine. If everything lights up and the starter now works, it's a bad ground.

If it still doesn't work, try hooking the jumper cable up from the positive battery post to the B+ terminal on the starter. (I assume that you know where it is, since it sounds like you removed the starter for testing).

One of these two tests should get us in the right direction. Poor/bad grounds are far more common than bad B+ cables though, so look closely at the battery ground and the strap connecting the transmission to the body. Measure the voltage drop across each ground with your multimeter with a load on, like the headlights. A good ground shouldn't have more than 0.2V drop.

[ossiblue]

It's not clear how the starter was "checked" or which contacts you jumped. Did O'Reilly's actually apply voltage to the starter and solenoid and found that both worked, or did they do continuity/resistances tests only?

The fact you have dimming dash lights does indicate a voltage drop so I suspect current is getting to the starter solenoid. Your problem sounds like you have a mechanical issue inside the starter solenoid or where the starter mates with the bell housing, preventing the starter solenoid from pushing out the drive gear and, simultaneously, shunting current to the starter motor.

Did you try jumping the two large lugs on the starter solenoid? Doing so will send current from the battery directly to the starter motor, causing the motor to run, but the flywheel will not engage and the engine will not turn over. That test lets you know the starter motor is good--you simply by-passed the solenoid. If you repeat the test by jumping the battery lug to the small connection where the yellow wire is attached--the test you likely already performed--and the starter fails to run, you've isolated the problem to the solenoid as all other elements of the starting circuit have been eliminated. It is not uncommon for a solenoid to fail to operate when installed yet test "good" on the bench.

If you decide to run the above tests, please update us on the results.

[911buff]

The starter was bench tested on their machine which cycles the solenoid and starter motor. The bendix extended and the starter spun. Likewise, in the car the starter will spin when I cross the contacts on the starter. However, crossing the starter B+ terminal and the solenoid pin (yellow wire connection) only a weak spark happens.

I previously removed the ground strap at the transmission, cleaned the strap and the connections and tested the continuity of the strap... all good.

I will try the jumper cable test and see what it yields.

I should mention that this a replacement starter. When this first happened I pulled the starter and the test indicated that the solenoid was bad. Once I replaced the starter, it worked fine for a few weeks and then back to intermittent starting. I then pulled both the battery and starter and had them checked at O’Reilly’s... both good. Is there something in the electrical system that is killing the starter? Voltage regulator, perhaps? Or the alternator, itself?

[911pcars]

+1. Good advice.
Once again. A bench test of the starter at the parts store should have confirmed proper operation, if indeed performed.

[911buff]

So I tried the jumper cable method and same result. So I have removed the starter and headed back to the auto parts store to have it tested, again. Maybe something in the system is frying the solenoid.

[dannobee]

The yellow wire gets voltage from the ignition switch. Put your head under there and make sure the connector isn't loose on the ignition switch. Shouldn't take more than 10 seconds. I've seen that happen before.

[911buff]

So, the starter is good to go... the problem is somewhere else in the system. Ran into an old mechanic buddy at the store and he thinks it is a grounding issue. I had cleaned an inspected the ground strap from the body to the transaxle and there is minimal voltage drop. However I did not check for an a amperage drop. His thoughts were that the ground has continuity but may not support the amperage that is required to fire the starter. So I am going to install a ground strap from the body connection directly to the engine case... to quote one of my favorite movie lines; “hell, I’d piss on a spark plug if I thought it would help!” So, by that thought process, I will try just about anything at this point. So, cover me, I am going in!

[911buff]

Turns out my mechanic buddy was right on the money; the ground was not sufficient to carry the amperage. I installed a secondary ground cable between the body and the engine case. Starter cranked better than it ever has! I did some cleaning around the mounting studs/nuts at the bell housing. I think the rear main seal is leaking, so that will need to be addressed but at least it starts now.