05 STS starting problem cont.....

[hiljak]

So, I've quit troubleshooting the starting problem for a while as it just quick happening for almost a month. Its done it twice this week and both times it ended up starting after "fiddling" with the relay and wiring harneses in the under hood fuse box.

Well, it did again tonight while it was actually in the garage (it usually happens conveniently when I'm out and about). I put a meter on the fat purple wire from the main engine harness that plugs into the fuse box. The fat purple wire gets 12 volts from the starter relay and goes down to the starter solenoid. I have verified that when the condition exists and car is not starting, I do get the 12 volts to the purple wire when the starter button is pushed.

This tells the relay is working, starter switch is working, etc.. If power is going to the starter solenoid and the starter is not engaging, does this mean the solenoid is bad? And could it operate fine and fail so intermittently? Can the solenoid be changed without a new starter?

Thanks for the support guys.

[hiljak]

Well, GMpartsdirect only shows a listing for a starter, no solenoid. $125.00. You think I should go ahead and replace the starter?

[Texas Jim]

This tells the relay is working, starter switch is working, etc.. If power is going to the starter solenoid and the starter is not engaging, does this mean the solenoid is bad? And could it operate fine and fail so intermittently? Can the solenoid be changed without a new starter?

Thanks for the support guys.

Sounds like you have prettyy well narrowed it down.

I just looked on ROCKAUTO and also DID NOT find a SEPERATE solenoid.

Hey guys, CORRECT ME if I am WRONG, but, my understanding of starters and solenoids are as follows.

On older starters, with a seperate solenoid, it is possible for the solenoid to work intermittently.

There is a large copper washer, inside the solenoid, that touches the internal end of the bolt that the main power wire attaches to.

Over time, it can get burn marks on it, (there is kind of an ARC) from the HIGH CURRENT DRAW, and not make good connection. I have had a couple do that. It usually would act up when HOT. Usually would start ok when cold. That could of been coincidence, I don't know for sure.

When you apply voltage to it, it energizes the solenoid and engages the bendix teeth to the flywheel teeth. Of course, the starter motor starts turning at the same time to crank the engine.

If one of the burn marks happen to be EXACTLY at the end of the bolt that the battery cable attaches to... it will not make a good connection. If you CLICK it several times... it will usually move enough to finally make contact and allow the starter to engage and start the car. I have had some where you had to short across the terminals of the solenoid, to finally make it work.

THAT IS NOT RECOMMENDED. These were older cars without all the high tech computers. I can't imagine what shorting terminals would do to the electronics of a modern car.

Is your '05 still under warranty? If so, I would try to get the dealer to replace the starter. I have not had the occasion to tear into a newer type starter, but I have never seen a starter without a solenoid.

Maybe the '05's solenoid is built intergal to the starter and is not replaceable as a seperate piece.

[hiljak]

I think it has to be the solenoid. Maybe there is a burn mark on it and the ramdomness of the no start condition is due to the "roulette" factor of the where the solenoid stops (on the burnt spot or not). All the fiddling I did may have been arbitrary and the actual condition went away once the solenoid moved from that bad spot??? Thats my best guess. I'm picking up a new Delco starter tonight locally for $199.00. I'll throw it on and try taking the solenoid apart on the old before I take it in for a core return. thanks,.

[hiljak]

changed the starter. I noticed once the old one was out, it makes a noise when you move it like something is loose inside (maybe a brush is loose??). The starter is a royal pain in the *smurf* to change. I had to drop the two rear engine cradle/subframe bolts, take the steering rack mounts loose, and the steering column linkage had to be disconnected just to get the starter out. .6 hours my *smurf*!!