Skip Wolfe

The good news is I got the racecar started, the bad news is the car doesn't turn off when I hit turn off the ignition switch or the battery cutoff. As most know, there isn't any stock wiring in the car and is just a compination of the TEC3 harness, Painless Racercar 8 circuit harness, Stack harness, and customs wiring. I am using one of the solenoid battery cut-offs http://www.batterycutoff.com/ as well as toggle switches for ignition, starter, fuel, etc. Both the ignition toggle switch and batt cut off work fine without the car running (turns on/off dash, TEC3, aux gauges, etc), but when the car is running, I turn off the ignition switch and nothing happens - event the little red light in the ignition switch itself stays on. I am assuming the alternator is powering the system somehow,

Battery is hooked up to one side of cutoff switch (cut-off switch has alt
Other side of cutoff is hooked to:
- starter and alternator
- Red 10 awg wire on TEC3 Power Harness
- B+ of painless wiring harness to power relays for starter, fuel pump, fans, etc.
- to the ignition switch

The ignition switch then feeds:
- Stack dash
- gauges
- switches to activate the relays that control the fuel, fans, etc.
- the switched power for the Tec3 - yellow 18 awg wire on TEC3 Power Harness
- exciter wire on the alternator

Any thoughts on where I should start looking?

Skip

Bri Bro

Are you turning off the DME relay input?

Skip Wolfe

This is all custom wiring so there isn't a DME relay - that is controlled by the TEC3.

95ONE

Start with ecu relay, work backwards. I bet power is getting to ecu through more than one sorce. Painless wiring feed, (ignition) tech 3 wiring feed, and straight from alternator through ign switch. Only way is to reverse engineer it since its custom. have to start with ign/ecu relay and go back. Oh wiring joy. (sarcasm) - double sarcasm on someone elses mess!

Bri Bro

OK, so is the TEC3 turning off the injectors and the fuel pump that were controlled by the DME relay.

HansB

Do you use the cut-off switch additional circuit (with the resistor) to kill the alternator? That would certainly take care of all the power.
I personally prefer to kill the fuel with a manual switch, that is the most certain and safest way to kill the engine.

Skip Wolfe

The TEC3 runs the injector and has the capability of controlling the fuel pump, although I have the fuel pump operating off of a seperate switch and relay. I have been using that to shut down the car while I troubleshoot this, but it takes 4-5 seconds before the pressure bleeds off and it stumbles and shuts down.

Automotive wiring drives me nuts - off to the garage to start tracing it out.

theedge

Try to get a big sheet of paper and draw out your system, as it should be. That might give you some clues. Perhaps you got something crossed somewhere.

George D

Considered installing a new ingition and key switch...they do go bad. The TEC3 only sees voltage. Seems like the switch would be the likely culprit.

G

Skip Wolfe

Where should the alternator exciter wire connect? Right now I have it connected into the switched power bus, but I am thinking this is not correct and that the alternator continues to power the switched power bus (an concequently the ECU, switches for the fuel pump relay, etc.) through this wire. When the ingition/cut-off switches are still on, I can disconnect the exciter wire after the car is started and it stays running. However, when I turn the ingition/cut-off switches off, and the engine stays running, I then disconnect the exciter wire and the engine shuts-off instantly.

So the exciter wire seems to be the culprit, but I am not sure where to hook it up - battery 12+? the starter switch so it only gets power when starting?

95ONE

Only power after starting.

Skip Wolfe

The keyed ignition switch is long gone - just has a toggle switch for ignition and a push button for the starter. You can see them to the left of the Stack dash - the red switch is ignition and the black one next to it is the starter button.

Bri Bro

Skip, that wire should be connected to switched DC power. It is a part of the security system, one lead to the DME relay and the other to the generator. I bet you have something else connected to that lead that lets the car continue to run. The alt exciter being disconnected will cause a slow death of the battery.

Skip Wolfe

Just seems wierd that with the ign switch off and this wire connected the engine stays running, but as soon as I disconnect it the engine shuts-off. power should be flow to the alternator via this wire not from it correct? So if I pull the wire with the switches on and engine running it should not read 12vdc correct?

George D

Not to go OT, but you have Chris's old shell? I'll have some of my friendly TEC GT engineer tuner friends read this post and let them give you their 2cents. I have the TEC GT in my car running with the stock ignition. They will be here tomorrow helping me install my recovered dash.

George