ignition switch engages starter after engine is running???
 

I just got my cobra running but I have a wierd problem, when starting the car, sometimes the starter will engage again after I return the key to the run position, sometimes just turning the key to the run position it will engage the starter, I have already replaced the switch with another new one, it seem to be okay for a day or two and then it starts to act up again, I have check the wiring for shorts ,it is a new wiring harness and very simple system.
I have a LA Exotic with a 428 and C6. Any suggestion would be appreciated.
Thank you
David

Do you have a firewall mounted starter solenoid? I am wondering if volatge from the igntion ballast system is feeding into your starter solenoid. This could be from the small guage wire on the solenoid being on the wrong terminal.

Yes I do have a firewall soleniod, with msd 6al ignition. I can not see how that would do that though.
David

Can you explain in detail exactly how you have the started, FW mounted solenoid, and the ignition key wired...

If your car had been doing fine, and this problem "just started to appear," then I would bet it's either a sticking solenoid or a sticking ignition switch. When I was having a similar (but different) problem I diagnosed it by disconnecting the starter from the solenoid and then putting 12v lights on the solenoid on both the 12v "in" from the ignition switch and the 12v "out" where you disconnected the starter. Then watch those two lights while you pretend to start the car by pretend cranking (obviously the car won't crank because you disconnected the wire going to the starter). That will test your ignition switch and solenoid. Both lights should light nicely while you are pretend cranking, and both should go instantly out when you let go of the key. If both lights stay on then your ignition switch is sticking. If one light stays on then your solenoid is sticking.

Well....at least you have something to check now.....either a sticking or improperly wired solenoid.

So......(I tend to blabber on when it comes to car stories), many years ago, I knew this couple where the woman was deaf. A spare key was made for the family Toyota, but the hardware store guy didn't de-burr it properly. The deaf woman started her Toyota the next day and the key stayed in the "Crank" position.

She didn't hear the screaming starter motor and proceded to the shoppping mall. She shut the car off and went shoppping. Upon her return to the car, it wouldn't start. The whole side of the starter motor frame had a large melted hole through it.

Just lucky a fire didnt start.

Now imagine a mechanic tracing that one back to the key !!!

As you have all ready replaced the switch, good move by the way, the next obvious step is to replace the solenoid.

Well let see if I can answer this good, I am not a good typist, I just finished puting the wiring harness in the car with a new ing switch and soleniod, two days later after setting the valves and checking the rest of the lights and guages I notice the starter trying to engage, the first time I just turn the switch on and not to the start position and the starter engage and started the car with the starter still grinding, I shut it off and tried it again and it worked fine, after turning the switch off and on several more times it again started in just the on position and stayed engaged. I thought bad switch or soleniod, so went down to Napa and bought new switch and soleniod, installed, worked great for about week, then yesterday while moving the car out of the garage it did it again, this time I thought it had ruined the ring gear as it hid hard, all I did was turn the switch on to turn the radio on and it started and the started stayed engaged.
Now as the wiring goes the ign switch is a 4 pole generic switch it has an ign pole, sol pole, acc pole, batt pole. The hook up is simple, Batt lead to batt, ing to ing , sol to sol and acc to acc. No special things add, I do run a MSD and electric fuel pump and fans. On the soleniod I have a wire that runs from the start terminal to the ing side of the switch so that when it is in crank mode it will give power to the msd. I do not think I have two bad switchs in a row but who know?????
As far a checking with the lights I did that and it is getting power to the soleniod sometimes just turning the switch on, it would appear to be a bad switch, but in the back of my mind I think something else is causing it.
Hope this help you to help me.
Thanks David

That at least tells you that it is not a solenoid or starter issue -- it's either a switch, wiring, or short issue. Have you tried the "jiggle test?" Turn you ignition key on, but don't crank the engine, and then "jiggle" the key to see if you can make the engine crank without actually turning the key to the cranking position. Then reach behind the dash to the wires leading to the switch and jiggle them and see if you can get your engine to crank by doing that.

What is the brand of ignition switch? Is it one of the off the shelf, cheapo auto parts store ones? I had 2 brand new ones do the same thing to me and wound up breaking a tooth off the flywheel. I picked up a different brand one (I think a Standard) and it is much better.

Anthony

FYI:
If you have a high torque starter, it comes equiped with a starter solenoid. That would make the firewall mounted unit redundant...

Your firewall mounted solenoid should have on one side (a big cable) a line going back to the battery and on the other side (a big cable) a line going down to your starter. Your MSD unit should (or could) feed from the battery side of this starter solenoid, along with any other full-time big power users. (driving lights, etc) MSD can always stay hot, very small current draw when off...If you send me an email with your email address, I'll send you some schematics of a different starter hookups. I seem to remember this problem before, a backfeed of power, but I don't remember from where...hmmmmm...I'll have a think....UPDATE: Info sent.

Well I tried the jiggle test , if I jiggle the key it will cause the starter to engage, if I jiggle the wires nothing happens, everything is tight, it points to the switch, I guess it could be cheap switch 29.00 napa switch, x two. I am almost ready to put a seperate pushbutton switch before it tears something up. this is not my first car to build, I have several under my belt, everything from a sterling kit car to a blown and stroked 34 ply hemi coupe, my current driver. I understand how wiring works and this may be just a bad switch twice in a row, but sure seems strange. I do not have a gear reduction starter, just stock.

That's a bad switch. I can't envision how it could be anything else. BUT, if you want to be absolutely sure, remove the solenoid wire from the back of the ignition switch and put a 12v test light on that ignition switch pole instead. Then repeat your jiggle test. If you can get the light to come on by jiggling the key then you absolutely, positively have a bad switch and you've eliminated the possibility of some cosmic back feed through the solenoid wire (which I can't think of how that could happen anyway).

I recently had a big thread about screwing around with my starter and damaging teeth on the flywheel.

I'll tell you what, the next time I even get a hunch I got starter problems I'm gonna STOP right there and get a handle on it. PITA changing out a ring gear.

...the new one works beautifully by the way. :)

Okay just ordered a new Ron Francis ign switch, will post what happens.
David

Dave are you running the current for ther fans and MSD dirctly through the switch?

No the fans run though a flexalite 33054 controller, the msd runs though the ignition switch.
David

You mean just the skinny red wire from the MSD unit, not the big fat Red one, right? That big fat Red wire needs to run directly to the battery, not through the ignition switch.

Yes just the skinny red, the fat red is at the batt.
I really think this is a ign switch problem, I just have a hard time believing that I got two bad switchs in a row, but anything is possible, the hard part of this is waiting for the switch to come and not being able to drive it.......
like waiting for Christmas morning.......guess I have not grow up yet.
David

Dave,

What wires do you have hooked up to the smaller post on the starter relay? If you are running MSD then you may not need to hook up anything here.

Bill