Intermitant starting, not battery, not interlock switch, not starter
 

Ok, I've replaced every thing between the ignition switch to the starter. And I keep having this problem. For reference, this is for a S4 Vert.

I press in the clutch, turn the key, and all systems react like it should when starting. Except, the starter sometimes turns over right away, and sometimes not. When not, I hold the key in start position and pump the clutch to click the interlock switch (the system can see every time I click the interlock switch) as little as one time and as many as 5 times until the starter turns over.

Cleaned the battery posts, same thing.

Replaced the battery, same thing.

Replaced the starter, same thing.

Replaced the interlock switch, same thing.

Used a bypass plug from a S4 that doesn't have the factory alarm to bypass the starter cut relay, same thing.


So I've replaced every working part related to the starting circuit, and the symptoms remain exactly the same, no difference.

I'm thinking I have a weak connection as some connector someplace between the ignition switch and the starter solenoid. Thus the same effect if I had dirty battery posts in the starter in that the starter can't draw enough amps from the battery to turn the starter motor, the solinoid can't draw enought amp to close the relay. But, I would think that unplugging and plugging the connectors would have some effect if that were the case. Should have gotten either better or worst simply by jiggling them around.

One more thing, although I don't think it's related. Sometimes the starter turns over faster than other times. But that showed up only after replacing the starter.


Thoughts, suggestions??

It's like this. That BLUE jumpered connector that I"m sure your familiar with has a BLACK/WHITE wire in it. That BLACK/WHITE wire goes directly to the starter solenoid. Need I say more?

IF you jumpered it from the battery, and the thing did not turn over, then you have a problem with the wiring.......large wiring, to the starter. Either the large gnd wire or the power wire. Maybe the small black/white wire from the BLUE connector also but not likely.

BLUE jumpered connector
 

Is what I was referring to when I described the "bypass plug from a S4". Did that to eliminate the Starter Cut Relay as being a possible cause.



By the way, I also replaced the power harness that plugs into the main harness by the steering knuckle. Same symptom before and after replacing the power harness.



It has to be somewhere between the interlock switch and the power harness connection since the system clearly see's the interlock switch a switch'n.

Found it. Actually cured a number of things such as the power windows moving quicker now.

The main power to the ignition switch comes from the main (80 AMP/100AMP) fuse. There is a single connector between the main fuse box under the hood and the battery. This is where the problem is. Since it's so close to the battery, the connector (only the male connectors were affected as I found on both my Verts) attracts corrosion from the batter acid fumes and creates a break in continuity between the copper wire and the copper spade connection sleeve much like if your battery posts get corroded between the posts and cable connectors by this same battery acid fumes.

Apparently, this corrosion would not allow enough amps to get through to the solenoid for it to fully engage the relay and/or cause the starter to struggle to pull enough amps through to turn over.

What I did to fix is remove the male connector from its holder (ice pick, lift the arm from the inside that holds the spade in place). With a really hot soldering iron, melt gobs of flux all over where the wire meets the spade connection to burn/flush away the corrosion. Then seal the wire to the connector with solder so the corrosion can't get between the wire and spade sleeve again.

Fully turns over with every twist of the key now.

This is probably the cause of loss of power to the ignition switch despite a good main fuse we hear complaints about on this forum from time to time, including from myself.

I had run a jumper wire from the main fuse to the ignition switch when this happened to me. That got things working again. But the residual quirks were apparently caused by the jumper wire being much smaller guage than the wire that was designed to bring power to the ignition switch. So, sufficient amps couldn't get through.

sweet! I have the same starting problem and window lag. I though my window motors were toast and my starter was getting old. Thanks for the inf0!!

My pleasure to contribute for future searchers to find.

Additional symptom. My plug-it-in-the-cigarette-lighter Magellen GPS just was not happy in my Vert. It would reboot when ever the car dropped to idle level RPM's (where the alternator just doesn't contribute much). The GPS is much happier now.