HOZZMANRX7

iTrader: (43)

Ok, this is a weird one. Hopefully someone has had this happen to them and can share a fix.

Background,

Complete S4 ASpec TII all stock swap into my S4 Vert. The only thing not swapped from the TII donor was the main harness. Decided that route as going to aftermarket boost gauge and wanted to retain the voltmeter. Ran a jumper wire from the alternator to the voltmeter feed wire for that purpose.


Anyway, everything was doing fine. Got her started Thursday (announced in a separate thread), everything operating like it should. Started her up and shut her down a number of times since, everything operated, as it should. Today started her up, and then went to shut her down as normal with the ignition key.............and weirdness set in.


Started her up, but when turning the key to the off position, engine runs on like I hadn't touched the key...gauges still function and everything. The only thing that visibly shut down was the clock.

Referring to the factory manual wiring diagram for possible suspects, I know it ISN'T the following things:


First thought that the ignition switch module had developed an internal short sending power to the main relay despite turning the key to the off position. But, swapped out the module with a different one, same problem. Engine continued to run on.

So, assumed the Main Relay was getting stuck. Pulled it and plugged it into another RX7, and it operated properly. So, that isn't the problem.


Any ideas out there? How the heck is power getting to the ECU to keep the engine running?

Icemark Mark, Guitarjunky Dave, anybody??

RotaryEvolution

iTrader: (30)

sounds like the ignition switch took a **** or if you have something wired into the ignition it is keeping the circuit powered up. any aftermarket accessories like an alarm?

HOZZMANRX7

iTrader: (43)

Aftermarket alarm is all But, been running the same set up for 6 years with no problem. And, all it does is make noise and flash the parking lights. No ignition kill, etc hooked up. But, to be sure, I disconnected it as well to isolate it. Engine still ran on.

And, again, not the ignition switch as I swapped out to a different one but no change in the problem.

I'd be suspicoius of the jumper wire from the alternator to power the voltmeter. But, engine shut down fine last couple days with that same wire connected.

RotaryEvolution

iTrader: (30)

youll have to pop the cover off the steering shaft and test the ign circuit to see if it is showing voltage with the key off or even just disconnect the ignition connectors and test it while it is disconnected as per the FSM conductivity chart.

'87 turbo II

iTrader: (1)

I have an alamr/remote start and to kill my engine when there's no key in it I push the break pedal. I'm almost 100% sure this isn't your problem but you can try it if you want.

HOZZMANRX7

iTrader: (43)

Will do that tomorrow.

Also, the engine will shut down if I pull the EGI fuse under the hood.

Any other suggestions?? A catholic priest with holy water perhaps??

Phantomkid

sounds like a cross short.... hmm have fun with that like. like karack said test the ignition circuit. when you have the switch off test the circuit. what is the last thing you've modified.

HOZZMANRX7

iTrader: (43)

Normally, that is the first place I'd look. But, nothing modified since the last time she shut down normal. This just came out of the blue sky.

HOZZMANRX7

iTrader: (43)

Comment from Icemark,

I'd be looking at that wire you ran for the voltmeter.

Normally the voltmeter gets its power from the same source as all the other gauges, and you should not need to run a wire at all.

I suspect that you blew the internal diode in the alt and it is back feeding the ignition circuit through that wire.

RotaryEvolution

iTrader: (30)

that is possible, easy way to find out is to disconnect the alternator connections and try it again.

84stock

iTrader: (5)

LOL, my 85se does the same thing! All I do is hit a pwr window switch after turning the ignition off and it stops running. Try that and let me know.

zerrorx7

thats funny i had the same thing with one of my s4....it was a gxl with a jdm engine swap and what i did..is i used a the fuel cut off to shut the car off. it works good and ut nevers floods....

Funkspectrum

iTrader: (5)

same thing happened to me. turned out to be my alternator.

HOZZMANRX7

iTrader: (43)

and it shut down as normal. So, replacing it should do the trick. Will update once confirmed for future reference for all.

HOZZMANRX7

iTrader: (43)

Ok I didn't describe one thing correctly. The additional wire run wasn't to power the voltmeter per se. It was to provide correct wiring for the alternator. Clarification is below.

Further the problem was solved this evening by my TII swap mentor/mechanic Robert, genius that he is.

For future reference:

Background:

We used the stock main NA harness and a stock TII ECU/injector harness for this swap. The only real issue from this approach is pretty much an alternator wiring issue (given decision to keep the stock voltmeter in lieu of the stock boost gauge). At issue is the stock NA ECU/injector harness includes the positive & negative (white/ black stripe and Black/White stripe) wires that plugs into the back of the alternator while the TII ECU harness doesn't (because in a TII those two wires run through the main harness).

Corrective action:
So. Robert (following the factory wiring diagram accurately) added those two wires to the TII ECU harness to make the wiring to the alternator complete. White with black, per the manual, is positive and mounts to the top spade and White with black is negative/ground running to the bottom spade.

Trouble shooting:
Disconnected the alternator as suggested, and everything worked fine. So, we knew the alternator was involved in the problem. Replaced the alternator, problem remained. So, checking with a voltmeter to make sure the wiring to the alternator was correct per the manual, and everything checked out per the manual. Obviously the manual is correct as the correct location for those wires in the connector. Right? WRONG!!!!!

Over my objection and with me putting up good money as a bet that what he proposed would for sure fry things more , Robert corrected the problem by switching the two spades in the connector (white/ black to bottom, black/white to top). Plugged it in and now everything operates as it should. Less money in my pocket, but problem solved.

Conclusion:
So, for future reference, anyone taking this same approach for a S4 TII to NA swap, connect the two wires that plug into the back of the alternator the reverse to the picture in the manual.

Live and learn.

Next week, the state referee for my CARB sticker.

RotaryEvolution

iTrader: (30)

grats and good luck

HAILERS

Bull. The black/white goes to the METER fuse and the White/Black is a ground for the alternator relay in the CPU.

When the alt is not putting out, it puts out a gnd signal on the white/black wire to the relay in the CPU to pull it in which in turn makes the lights in the Warning Cluster all come on.

Almost everyone of these (My car won't shut off when I turn the key OFF) threads leads back to the alternator wiring backfeeding the ignition switch. Done

LESSON: When putting a turbo engine in a series four n/a, use the stock non turbo harness. There is not a damn thing to be gained using a TurboII Emissions harness in the n/a car except the Knock Box which is so damn simple to wire it's pathetic.

HOZZMANRX7

iTrader: (43)

Can you describe the re-wiring, or provide a link to a thread that does?

Preparing for this project for over a year (actually longer), I've been following every swap thread I've seen, and this is the first I've seen that the NA Emission/ECU/injector harness can be used with minor modification.

fc3s91

iTrader: (23)

True according to the manual. But by switching the wires, The problem was solved. In my opinion the t2 harness is easier to wire up than the na harness. Just follow the manual!!!!!. So it runs good and drives great.
Thanks Robert