beltrunner

On my '93 T/A I'm trying to install a VATS bypass module. I finally located the damn factory module by removing the radio. It's on the passenger side between the airbag bracket and the A/C duct. I can barely put my fingers on the top plug, but I am not able to pull it off. There must be some sort of lock on the plug, which I can't even see. How the heck do I get this thing disconnected and hook up my bypass module? The car stalls out on a regular basis now, so I can't drive it until I get rid of this factory theft junk. I read shoebox's article, but I still cannot see how to access the factory module. Any suggestions or tricks would be much appreciated (pics would be great). Thanks.

beltrunner

I've gotten conflicting information on this system along the way. My car will be running fine, and then just shut off. It cranks, but will not start up again for another 5 minutes or so. Then it cranks and starts up, and might run for awhile until it suddenly shuts down again. Some say this is the TDM. But others say that once the motor is running it does not need the TDM signal to the injectors so that a faulty TDM is not what is causing my motor to shut off. What is really going on here? Thanks.

Injuneer

Which "bypass" are you trying to install....

A system that totally replaces the TDM, reading the key, providing the signal to the starter relay and to the ECM for fuel enable - multiple wires connect to the TDM harness connector, requiring unplugging the module?

or....

Just the 3-wire chip that sends the 30 or 50Hz signal to the ECM for fuel enable - power and ground to bypass module, snip the dark blue wire from the TDM and connect the bypass module's frequency signal wire to the piece of the dark blue wire that goes to the ECM ?

Injuneer

Did you follow up on GaryDoug's last response to your earlier thread?

https://www.camaroz28.com/forums/fue...roblem-882309/

beltrunner

Thanks for the quick reply Injuneer...I did go over all the wiring that I could get to without disassembling stuff (unscrewed and cleaned all the accessible terminals..twisted & jiggled everything I could get to, and no problem showed itself). I have already plugged in a bypass resistor module at the steering column which seems to work fine. But at times the motor just turns off...cranks but won't restart for 3-5 minutes, and then restarts. The other bypass module I purchased is a 3 wire from Baker Electronics. They told me that I didn't have to cut any wires, but just use a wire tap to hook their signal wire to my blue wire, and their red wire to a "Run" hot wire, and their black wire to ground. I would be okay doing it this way since I don't see how to physically remove the TDM without sawing the car in half first. I haven't hooked up their module yet. I still don't understand for sure if a bad TDM will cause a running motor to shut off...or if it will only keep the motor from starting in the first place. Thanks for the help on this.

Injuneer

The fusible links that he suggested you check are easily accessible at the red "+" distribution box near the battery.

My understanding is that if a component in the PASS-Key system fails while the engine is running, the "SECURITY" light will turn on solid and stay on, indicating the system is no longer protecting the vehicle. Failure while the engine is running should not shut the engine down. That would be extremely dangerous.

Now, if the TDM was losing power intermittently, not sure what would happen. But the PCM should only need the fuel enable signal to allow the engine to start. To me it looks like there is an intermittent power supply or ground loss to several components, including the TDM and the PCM.

I was surprised to see this post, since I didn't feel like the previous thread had reached a resolution as to the source of the problem.

beltrunner

If a bad TDM won't make the car stall, then it looks like I'm back to square 1 with this thing. This intermittent stalling has been going on for some time, and I don't know what to check out next. When it stalls out, I would like to check it for spark or fuel, but it has always started up again by the time I can get out of the car and get set up to check it. Things are looking gloomy right about now...

beltrunner

Well today I finished installing the TDM bypass module, and hoped it somehow would solve the problem. The car started right up and idled perfectly for 15 minutes. I revved the motor a little and was about to put it into gear when it suddenly shut off. The tach went dead, and then the dash warning lights came on (no security light though) as the ignition remained on with the motor stopped. It would crank but not start. I tried ten times in 30 second intervals, and it would not start. It took me about 2 minutes to grab some test tools to check for spark. When I cranked it the motor started right up and has been idling for almost an hour with no problem.I've done fuel pump,ignition switch, ignition module, and wiring checks to no avail...My wife wants me to call Father O'Leary's orphanage to pick up my beautiful car.

beltrunner

Hooray...after not ever throwing any codes since this problem began, I finally got a P046 code (fuel enable?)...where do I go from here?

Injuneer

Is it possible you loosened the harness connector when you were trying to reach the TDM and disconnect it?

The code means the ECM did not receive the fuel enable signal from the TDM. The 3-wire chip provides the fuel enable signal, assuming you purchased the correct frequency.

But it will not fix/replace a totally failed TDM. The TDM reads the key resistance to verify the key, then sends the starter enable ground to the theft deterrent relay.

beltrunner

Yeah, I did loosen the plug for the TDM when I was trying to disconnect the thing. I then tried to start the car, and no crank at all. I managed to snap the plug onto the TDM and the car then cranked and started. I've placed a resistor module under the steering column, and put the Baker Electronics module onto the blue wire at the module plug. The car starts every time and runs until it stalls, and then cranks but will not start for a couple minutes. It idled for over an hour in my driveway without stalling. I've restarted it over a dozen times since then without a problem. I live in a hilly area and I'm afraid to take it out and stall it so I can't easily get it back home again. I read on some site that a faulty ECM could shut off the fuel while the motor is running. I don't know what to check for next. I have a life time warranty on my most recent OPTI, and wonder if I should replace it for the heck of it. When the OPTE went out 4 years the car would crank but not start at all.

beltrunner

Here's my update on an extremely intermittent stalling condition. After doing fuel pump, ignition switch, ICM, and VATS Bypass, the stalling became more frequent, but still no codes, and not dead long enough to check out stuff. So I replaced a 2 year old AC Delco OptiSpark with 3000 miles on it with an Oreilly's Rich Porter distributor. It's been about 2 weeks of steady driving now and the car runs perfectly. Seems this might have been the problem...I hope. Thanks for all the help along the way.

beltrunner

AC Opti was replaced 4 years ago with with Rich Porter unit (lifetime Warranty). Apparently failed with about 3000 miles on it. Replacement unit works for now.