Hello, I am working on a 1971 Corvette with the 270hp 350. I installed the Pertronix Ignitor 1181LS into the stock tach drive distributor (and shimmed the gear at the same time). Then I installed the Pertronix Digital HP together with the .32 Ohm Flame Thrower III coil. The motor immediately fired and the ignition box started to flash code 42 (four long flashes followed by two short flashes). I contacted Pertronix Tech Support and was told there is no such thing as a '42' diagnostic code and to request a new unit. Summit was very helpful and immediately dispatched a new kit. In the mean time I checked all wiring (10 Gauge wires directly to the battery), wires to coil separated from the trigger wires, 12 volt ignition (which taps into the IGN port on the fuse box - the one the power windows are connected to). Everything checked out, and I even replaced the horn relay junction box, new Powermaster alternator and also starter.

The new Pertronix HP with FlameThrower III coil kit arrived and I installed it (new coil and new computer). Exactly the same thing happened, car fired up and flashed diagnostic code '42'.

Tomorrow I will probably pick up a new battery (the one I have checks out and was checked at NAPA with their diagnostic tool - but who knows maybe it is bad - 2 years old). Please let me know if anyone has experienced this code of '42'. I am not super excited about calling Pertronix Tech support again to be told this code does not exist and to check my ground (I can't tell you how perfect my ground is and the 20 additional ground wires I added). Clearly it does have a '42' code and the engineering department certainly knows about it cuz they programmed it in. I am frustrated. According to the instructions, the ignition box will shut down functionality depending on the error including the multi-discharge feature. So with an unknown code there is no way to know what the box is actually doing.

Maybe I am missing something? Something else to check? Any help is appreciated. Thank you!

 

2 units in a row with a issue? Tech support is no help?
Move forward, Contact DUI in Tennessee. Have them make you up a custom curved distributor. Stab it in. Time it and drive on!

 

Did you check alternator output voltage?
Did you check the coil connections?

 

Yes, I checked alternator output around 14.7V (brand new Powermaster). Like the MSD box the coil receives both + and - input from the box itself (no connection to switched 12V or distributor wire). The Pertronix computer has a 12V switched input wire. I checked all these voltages with engine running and off (~14+ volts running and ~12.7 shut off). I am stumped. I guess I would just keep digging through the electrical system but since I have a diagnostic code '42' which is claimed not to exist perhaps this diagnostic code means my electrical system is the best the computer has ever seen, or it is the worst or something in between, have no idea....

I like the above suggestion to just move on. Excellent advice, and hard to do when there is a mystery attached and a tech support line claiming the code does not exist.... when obviously it does.... Kinda makes a feller want to dig in...... big mistake....

Oh, I also just ordered a yellow top optima for the car. Figure throwing more money at it will help. right?

 

14.7 is on the high side. Is this with a fully charged battery that has been load tested.

 

The battery is a two year old NAPA Legend that is usually connected to my Optima trickle charger. I brought it in to to NAPA and they attached it to a diagnostic device which returned 'Good Battery' with 750 or so cranking amps. I was also wondering if this included a stress test, but I don't know for sure...

I do have a new battery on the way. Optima yellow top 750 CCA... I feel kinda dumb just buying stuff to fix mysteries.....

UPDATE: Just got off hold with Pertronix while typing this very reply. Explained the situation and I pushed the topic of maybe the engineers stashed a code in there they didn't publish. On the second push, or third, it just so happened an engineer walked past the tech support dude (he told me this, as I am not there) and he asked the engineer. Engineer responded that yes, there is such a code indicating voltage drop at start up and that it is non fatal, so ok to drive. I was very VERY thankful for the tech support dude inquiring for me to find this out. This kind of outcome has like 0.0001% chance of happening so I feel lucky. Also thankful for the rapid responses to help on the forum. Thank you!

 

Thanks for the update. Are battery cable connections good on both ends of cables?

 

Just checked them again! The battery terminals are brand new brass and the + and - cables from the Pertronix box are routed directly to these brass terminals with brand new 10 guage sheathed cables (I ran it along the brake and vent lines on driver side and drilled a hole in the side of the battery compartment). The resistance from these cables to the battery terminal ends is ~0.2 Ohms. The only improvement I can think of would be to solder the 10 gauge cables to the box wiring harness (the harness wires are ~12 gauge ) instead of using the crimped connectors. But dang, if everyone else uses those....

The 12V switched IGN source for the ignitor lobe sensor (in distributor) as well as the switched 12V wire on the Pertronix box is coming from the IGN port in the fuse block. The same connector that goes to the power window relay. I hope this is OK (there is a pink Y connector already attached for the power window relay wire). I checked the resistance between the IGN port and ground and the meter displayed ~4.5 Ohms (have to admit I was expecting ~0.2 Ohms). It shows 12V with battery installed and key rolled to IGN.

 

Have you measured the voltage while you crank? If the Pertronix sees 10 V during startup, for example, could that trigger the code?

Maybe it's your battery, but I'd check the starter circuit, especially the chassis ground, and at the starter.

 

Thank you for the additional ideas. Yesterday I inspected the + battery cable at the starter, polished up the terminals and attached them to a brand new Powermaster OEM appearance starter (this required modification to the trans inspection cover as it did not clear the machine work on the new starter). I inspected the cable connecting the starter + terminal to the junction block/horn relay (and replaced the horn relay with a new one). Horn works fine. Yes!! Celebrate..

I cleaned the terminus of the cable going to 'S" terminal on starter. I suspect this goes to the ignition switch as it fires the solenoid. I think...

I have disconnected the wire to the 'R' terminal on the starter that used to deliver 12V (no resistor) to the coil at startup (the coil is now direct attached to the Pertronix box).

With all of your help I am trying to exhaust all opportunities to correct gremlins. New yellow top Optima should arrive tomorrow. Another $300. sigh....

 

Have you inspected the ground cable that goes from the block to the frame? I had a bad one a few years ago. Caused a lot of little issues.

 

Thanks, I did replace this cable ground and sanded / cleaned the surface of the block and starter bracket.

Last night it occurred to me that maybe the neutral safety switch is bad? Big short dragging the Vs down when starting? The wire connected to 'S' on the starter originates from the neutral safety switch. I have yet to open up the dash or console... You know, its like a jungle in there...

 

I think I just got seriously skooled. I took apart the console and unplugged the neutral safety switch. Checked both purple wires on the connector heading under the dash for short with ground. One wire showed no conductivity and the other showed 0.2 Ohms - so full connection with ground. I disconnected the plugs to the ignition switch (there are two) and the purple wire showed conductivity with one of the purple wires in the plug to the neutral safety switch and no conductivity with ground. So I traced the purple wire with conductivity to ground all the way to the solenoid terminal on the starter. So the solenoid terminal on the starter is a ground? I didn't know this....

Can someone tell me what are the wires in the second plug in the ignition switch? There are three wires red, orange and black. The orange and black appear to be connected.

 

Wiring diagrams below. You have opened a can of worms now.

Before you break anything, Did you check for voltage sag when cranking the engine? Dirty contacts, or failing cables, will cause the voltage to dip.

https://wordpress.keystonestatecorve...m/?page_id=118

 

Here's a good "how does a starter work" video, cued up to the solenoid discussion.

 

Yep worms everywhere. Multi colored worms and vacuum hose worms. I thought I had found a massive short, but it was just the solenoid coil to ground. Almost everything I have learned has had severe pain associated with it.

Good video, honestly never really knew what was going on in inside the starter other than some serious spinning of gears. When the worm clean up is complete, I can check for those voltage drops.

Thank you.