HELP - Weird starter circuit problem.

[gsodonis]

I have a weird problem that has recently surfaced and need some help from you 5 and 6-speed SVXers. After driving to work 40 miles this morning (and once last week), when I press down on the clutch, my starter tries to engage with the motor running. Obviously, the NSS is initiating the problem, but it is only a dumb switch, so replacing it probably won't fix the problem.

When I step on the clutch, it takes about a half second and you hear a loud click somewhere behind the dash, then simultaneously, the dash lights dim and the starter engages (you know that horrible grinding sound). The first time it happened last week, Wednesday, I got a CEL 12 (starter circuit error), but after sitting in the parking lot for 4 hours, the problem never duplicated itself that day or the rest of the Thanksgiving holiday.

What makes up the starter circuit? I know we have the switch on one end, and the the relay that sends a signal to the solenoid and the starter itself in the engine bay. Does all of this run through the security module? Has anyone ever had this problem?

As always, your collective help is greatly appreciated.

[PhatWeasel]

I may be totally off here, but the first thing I would check for is some portion of your clutch linkage crushing or pinching your wiring harness somewhere. Possibly under the dash? There are quite a few wires that would become refugees after installing the clutch pedal for a manual transmission. They might be trying to migrate back home.

[gsodonis]

I printed up the wiring diagram for the starter circuit and have deduced the following:

The item that is malfunctioning must have a 12V power source to allow an errant signal to go to the solenoid, so that rules out the NSS and the Security Module since both of those are effectively starter interrupts. If either of those malfunction, the worst they would do would be to PREVENT the starter from engaging. Without a 12V supply, neither of those can generate the 12V signal to the solenoid, only ALLOW it to get To the solenoid. At this point, the only items that have a 12V supply are the ignition switch and my starter relay MOD.

I suspect it may be my recently completed the 12V starter relay MOD. I'm going to replace the relay with a known good quality one. The one I used came with my PIAMM air horns. Since the airhorn set only cost me around $20 new, the included relay can't be of the best quality. I'm going to NAPA and buying the best relay I can find.

The reason I suspect that relay is that I have only started having this problem in the past week, just a few days after installing the relay MOD. The problem only occurs after prolonged highway driving, which leads me to believe the issue is engine bay heat soak related. Since my relay is a cheap plastic one and it has a 12V running to it, any malfunction of it (shorting closed) would cause a 12V signal to be sent to the solenoid. The NSS is the item that allows the starter circuit to be complete.

I'm still a big fan of the starter relay MOD, but if this works, I'll warn everyone to use a quality relay. Stay tuned..

[gsodonis]

It was the starter relay mod!

I replaced my freebie PIAMM air horn relay with a continuous duty one from NAPA (AR204 - $17.00) and my problem went away. When the PIAMM got hot, it starting shorting closed, sending a start signal to the solenoid, causing my starter to engage while the engine was running. Luckily for me, I have a 5-speed and it only happened when I stepped on the clutch to change gears. Shifting clutchless, each time it happened, I was able to get the car safely to my destination without doing any permanent damage to my starter or ring gear.

If you encounter this problem, be sure to upgrade the relay.