So I bought this 88 NA rx7 last summer to swap a s4 turbo engine into (old engine was toast) which I did, and I have it running good.
The only problem is, when I park the car and turn the ignition off, the car stays running. Forever. (at least I think so, I've never seen it shut off by itself and HAVE sat there and waited). I have to shut it off via the fuel pump switch which was wired in from the previous owner.
The car has a code alarm installed, which after going over the wiring diagram for it, I don't think that it controls the ignition. It does have a wire spliced into the ignition wire coming from the key, but the wire was not cut and re-routed. I think the wire spliced in is just to sense whether or not the key is in the on position(?).
I'm about to install my MegaSquirt ecu, but want to make sure I can shut the car off safely before doing so.
Any ideas what's wrong? What to test? I can't seem to find anyone else with this problem except for FD's with fried wiring.

 

Just to add some more info, the car starts right up after with no problems after I do manage to shut it off. And also, when I do cut the fuel, it kind of diesels for a second until it dies (bogs down but is trying to run still until it cant because it used what pressure was left in the fuel rail).
It seems as though it always has spark, even when the key is turned to "off".
Just in case it helps, the car does have a small electrical drain when it sits. It's fine to sit for a few hours, but if it's going to be sitting for a day or two, I have to disconnect the battery or the alarm goes nuts because the battery is too low (it wont turn over after that either until jump started).

 

One thing to look at is the two wire plug at the alternator. The Black/White wire should be positioned on top of the White/Black wire. Having them reversed would be a cause for your problem. So would having one of the ignition plugs mixed up. One way to check is if the wipers or turn signals work w/no key. They are supposed to work w/key to on and if they work w/no key then you know the cause.

 

Thanks for the reply, although wouldn't my alternator not charge the battery if the wires were reversed? I know the wires your talking about so I'll try that if my wipers don't come on with key off. It definitely does charge right now though.

 

Also just to clarify, you're referring to the back of the alternator when you said the black wire should be above the white, not in the orange connector under the dash right?

 

Back of the alternator.

And use the info provided in the following link: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/car-wont-turn-off-987661/

 

2nd place to check is the wiring of any added e fan , you must use a relay, failure to do so and the fan will windmill down as a generator and backfeed the ignition

very common mistake made under shady trees

 

The car still has the stock clutch fan.. for now :P

 

Based on the symptoms, the only thing the fuel switch is doing is cutting the fuel and therefore what seems like dieseling. I would take the alarm out and put everything back to stock. My guess is that the PO wired the alarm wrong.

 

Ok so I just checked the alternator, and it turns out the Black/White is on the bottom right now. It's a little late to start my car (straight pipe :P ) to test if swapping them fixed it, but ill give an update tomorrow.

If not.. guess I'm going full-out with my wiring, including ripping the alarm out and re-wiring that section too.. oh boy, lets cross our fingers

 

SWEET! It worked, thanks guys!
Thankfully I don't have to do the alarm wiring... lets stick to one rats nest at a time.