Yep, it works great. Follow what I wrote here and I think you’ll have positive results.

Glad I could help!

Matt-

Good points! I’m not going to lie, I didn’t bother to test the starting wire’s voltage with a multimeter because I was partially lazy and also didn’t feel the need for it. I knew it was getting voltage drop so the actual measurement wasn’t particularly important, since whatever value it’s dropping was obviously enough to not be able to trigger the solenoid.

IF this wasn’t the case, I still wanted to give the rewire a shot first since I have replacing the starter as the next and final step.

As you mentioned, even newer vehicles suffer from voltage drop. Mazda’s convoluted setup is really a factor in making things worse for these RX-7s. The ignition wire jumps through like 3 different relays including the security relay and the clutch switch. Voltage is being reduced at these hops, where exactly I am not sure, but it is a common enough of an occurrence to be a widespread problem in RX-7s.

I know the starter relay is technically a workaround, but it’s still a simple enough and effective enough of a workaround that should last.

My other plan was to actually rewire the ignition wire entirely so it bypasses all the in between relays. I could fiddle around and try to find out exactly where the voltage drop is occurring, but I’ve already bypassed the security relay to reduce a failure point, I think it’s a better solution to just rewire and bypass everything all together. I might do this if I end up swapping the starter out. It’s a really easy job to run a new wire from the thick Black/Blue wire, right before the security relay, all the way to the starter. I’m sort of 50/50 about this route because I kind of want to retain the clutch start feature. I know it’s not necessary, but whatever.

Have you tested the available voltage at the starter signal wire to see what it actually is?
If you’re getting less than 9 volts, this relay might help you but I would consider it a “bandaid” fix. It’s obviously not a hack job or anything like that. The relay install is very clean and professional. I’m pretty sure the 20+ year wiring harness isn’t helping your cause.

From the ignition switch to the starter, the starter signal wire probably goes through multiple connectors, and each connector should consume 0.01 – 0.1v. ( This spec only applies to the starter signal wire, normal wiring connectors should consume less than 0.01v ) Even newer vehicles, You can see up to 1.5v voltage drop from the ignition switch all the way to the starter.

I could double check to see how many connectors but I do not have the wiring diagram handy. If you happen to have a connector that is consuming (voltage drop) more than 0.1v, it could be a simple fix as cleaning the connector, repairing poor pin fit, etc..

If this is the case and you have a connector that is consuming more than it should, this bad connector might affect other electrical systems in your vehicle.

I think the reason you’re seeing Pettit selling these booster relay kits because most people will have issues trying to trace down the actual problem. It would be easier just to bypass the fault and install a relay in their eyes.

A multi-meter, a wiring diagram, connector locations, and some time, you could chase down the issue and repair it for good.

Just a thought.

Tommy, I agree, a plain bad starter or bad contacts are certainly possible causes, but I didn’t think it pertained to my context exactly and let me explain. The starter on my tranny is very low miles and it just didn’t seem to be the likely culprit. I actually did buy a backup starter just in case and chose not to swap it in yet until I tried this rewire.

The reason why the solenoid clicks is due to insufficient juice / low voltage at the energizing coil, which can certainly point to the Mazda ignition wiring and circuitry as being at fault. Something is causing the solenoid to not get enough voltage. It might be bad contacts, but I think voltage drop through the Mazda wiring is very much feasible.

There is sufficient evidence to support this since the issue appears to be chassis specific, plenty of the factory Rotary guys are having the same problem with the clicking. If so many people with even bone stock FDs are experiencing the same clicking, the numbers made it worthwhile to try. Which is also why Pettit saw the need to sell and market their starter booster relay package. I think in my case, it just became more pronounced after the swap and the GM starter. This is what convinced me the most to be the cause.

I will test this out and see if it holds up and report back. If it doesn’t work out, it is very easy to reverse the relay install and then I will swap in my new backup starter as the next step.

It’s not common for most cars to only get 10.5v of available voltage at the starter solenoid wire (signal wire). If you ever taken apart a starter or rebuilt one, you will understand that this relay will most likely not fix your issue. The solenoid does not need a lot of amperage or voltage for it to work. All it does is move a plunger and connect larger 12v battery cable to the starter motor via an internal contact.

It sounds like you just have bad contacts in the starter itself.

You could get a replacement starter or change the contacts out yourself.

Good Luck.