Got a 1994 Camaro a few weeks ago, when I got it it would start but wouldn’t stay running and shortly after it wouldn’t start, fuel pump primes, starter makes no noise, security light won’t come on at all.

from what I’ve researched and what I’ve tried diagnosing I believe there’s something causing the TDM to not work.

Idk if it’s necessary but to go through the steps I’ve taken. First I located the TDR and tested to see if power from the ignition switch was going to the relay, I tested to see if power was going from the transmission position switch to the relay and both checked out. I then tested to see if power was making it from the relay to the starter solenoid and it wasn’t. From there I pinned and manually ground the ground coming from the TDM to the TDR and was able to get the vehicle to start but it still wouldn’t run.

At this point I think there is something wrong with the TDM that isn’t sending the fuel enable signal. However I can’t really reach the TDM, I was able to finally see it behind the radio, but I have no idea how I would get it out to do a visual inspection or any tests, at least not without taking down the dash which I really would rather not do.

I’m looking really for any advice. I’ve seen a TDM bypass on Amazon, and I’m thinking I want to try that out, but I’m not really sure on how to install it. From what I’ve researched it seems it can be installed right by the PCM and that I don’t need to get in by the TDM to install it.

I apologize if any of my terminology is off, this stuff is still relatively new to me.

 

Do you have a way to scan the PCM for codes? In addition to grounding the theft deterrent relay, the TDM sends a 50 Hz signal to the PCM that tells the PCM it’s OK to activate the fuel injectors. If that signal is not received at startup, the PCM sets code DTC 46.

Here's an excellent description of the PASS-Key II system operation and troubleshooting:

4th Gen LT1 F-Body Tech-PassKey/VATS

There are also 2 fuses that supply power to the TDM:

http://shbox.com/1/pass_key.jpg

The 50 Hz signal from the TDM can be replaced by a “VATS bypass”, typically available on eBay or Amazon as you noted.

I haven’t accessed the TDM because I never had a problem, but I believe people who have bypasses the 50 Hz part have done it without “taking down the dash”. And I no longer own my Formula, so I can’t go and look at the TDM. This is where you require input from someone other than me.

 

Purchased the TDM bypass from amazon, gonna try and install it this weekend, will update after.

 

Did you check for Codes first????

 

No I don’t have a way to check for codes, I looked into getting something to read them but it’s a bit of an investment. I figure that there is a chance that it would be beneficial in the future if having this vehicle, however being as the TDM bypass is only 25 dollars I’m gonna see how that works. Going to go get a couple feet of wire from the store now.

 

There's excellent free software that will pull codes with a PC/laptop. Specifically written for the 1993-1995 LT1. Provides codes, two way communication to clear codes and activate systems to test them, and provides data on ~50 sensors and PCM parameters. Covers the PCM, ABS/EBCM (non-TCS), AIRBAGS - Scan9495:

https://www.camaroz28.com/forums/com...95-lt1-874306/

How to interpret LT1 PCM data:

https://www.camaroz28.com/forums/com...-guide-886891/

Only cost is for a cable to connect your PC to the DLC connector. A lot less costly in the long run than playing "parts replacement roulette".

 

Wow thank you so much I’ll definitely check that out! Good news is that the TDM bypass worked! Car is now running. Considering posting a YouTube video about my setup just to give a bit more knowledge to the subject to the internet. This forum was one of the only places I could even find discussion of a TDM bypass, most the info I found was just to bypass the VATs key.

 

Have you posted the YouTube video?