Soviet

I've got good or bad news. I got the car warm to the point where it barely started. Swapped in my roommate's battery immediately after which is good and has never been in my car before. I even charged it to make sure it was good. The car still had difficulty starting. So.... If I've changed both batteries and starters I think the issue must be an electrical connection somewhere... However the starter that I did put in looked pretty beat up. I think it came off a 2001 with 111k miles.

Here's a video showing the symptoms persist.

[media]http://www.youtube.com/watch?v=MUDEnegq2G8[/media]

I've just been trying to avoid trying the connections on the starter since its so damn hard to get to. At this point I might just swap starters from my other S which has had zero issues. If I do, I will try to test the starter with the multimeter.

Anyways I got to thinking and started to take a look at the starter that I pulled out. I noticed that the connection from the starter solenoid to the solenoid motor? is pretty filthy. I should have looked more carefully at the starter that I put in.

flanders

Hmm your dash almost shuts down, this seems it's not only the starter motor that doesn't get enough power.
I'm thinking maybe that short ground cable between battery and firewall has a bad connection.
Do you have any jumper cables? Try to connect one between battery negative and somewhere on the motor (bare metal).
Or do a voltage drop test on the negative side.

Slowcrash_101

Have you checked the starter relay? Checking resistance in a powered circuit isn't going to tell you much, I agree with above, a voltage drop will tell you if you have excessive resistance, even better would be a starter draw test. The starter should be pulling between 130-160 amps, any more than that and you can start suspecting the starter, or an electrical connection to it. I'd start with the relay, put the positive probe before and the negative after the relay. Set it on volts, the relay should read less than a volt when cranking.

james0933

Guys, voltage drop test.

flanders

Just for reference, the stock starter motor will pull over 400A for the first few ms.
You probably wont see those peaks with a regular amp meter though

Slowcrash_101

A starter draw test is done for 5 sec minimum.

Soviet

I just performed a voltage drop test against the battery terminals/clamps and against the negative side/firewall ground. No voltage drop. I am going to move towards the starter now.

Slowcrash_101

Unplug the fuel injectors, or cam sensors before you do it to prevent the car from starting when you do a starter voltage drop test. Run the positive lead from the battery terminal and the negative lead on the starter cable. Crank car for 5 seconds, if you have near .5 volts or more, you have a bad connection.

Soviet

Final update. When I finally got to the starter I discovered that the 12mm nut on the starter relay was loose (from my re installation). I tightened it up and I have zero issues now. The car starts amazingly well cold and hot!

So in closing I'm not 100% sure what the issue is but it was fixed in the process by removing and replacing the remanufactured starter with a used OEM unit.

I had never touched the engine since owning this car and I've had it for 30k miles. The issue that I've been seeing has only manifested lately so it appears that the old starter has actually gone bad or the electrical contacts may have lost some current. Hopefully this thread will help people in the future diagnose their issue!

windhund116

Thanks, for the follow-up post. Hopefully, no more starter issues.