code 46 and having rare start after VATS bypass
 

Hello I am desperate for advice on what to do for the last hurdle to my engine swap. After getting my 1991 350 L98 engine complete with uncut wire harness and ecm installed I tried to crank her over and got fuel pressure, spark, starter but no injector action. I witnessed the car start and run that the motor was in when I bought it. My injectors are all 15 ohms on drivers side and the front two passenger ones are 15 ohms and the back two near distributor are 14.7 ohms. I am getting power to the injectors on both sides of the injector connector. I am getting a code 46. I have had the car start randomly a few times out of probably 200+ cranks after doing many different things. doesn't seem consistant. It runs perfecty and gets up to temp and idles smooth. after letting it reach temp I shut it down and try to start and it just cranks doesn't even cough or stumble. 99% of time it just cranks as if it was out of gas. 1% of time it starts without hesitation and wont restart when I turn off and back on. Things that are new or replaced.
-starter
-ignition control module
-ignition coil
-plugs
-wires
-cap
-rotor
-ecm (still using original PROM)

My car is a 1987 that had a 2.8L. I have done all wire conversions that needed to be done in the C100 bulkhead and the C207 connector. I also eliminated the C221 connector and integrated those wires where they needed to go to mate to the 91 engine wires. I have been working on this issue for a month now and rly need my Camaro on the road to enjoy before snow flies in NY.

Things I need to know are:
Will the car atleast start without VATS connected or with a VATS error? Many people are telling me including the manufacturer of the module that its not the bypass because it would still start and die after a few seconds? but why the VATS 46 code?

The ECM grounds the injector wires to allow for pulses to spray fuel. Is it possible the PROM is causing this? When I got the new ECM I checked all input and output from every single wire that plugs into the ecm and all measurements are normal. Checked all fuses and im just rly stumped. When I did wiring I had shop manuals for both years and followed them strictly and soldered all wires and repined anything needing to go to a connector. I wanted this done right so I spent money on things to do it right and took my time. I am trying to be logical and patient but im out of ideas as I have never delt with VATS systems before. One thing worth mentioning is my ignition control module was failing 9/10 tests when I had it tested so I replaced it. Havent checked new one and maybe should so I know im not frying them if someone can give me proper diagnostic instructions as the book is very vague for this sensor or I can take it to autozone again if this is suspect. All grounds and braided cable are connected.
I suspect the module I bought from bakerelectronix.com but need to get it tested on an oscilloscope to confirm its outputting 30hz and 50hz properly. They said to use the 30hz signal to pin F10 Dk blu wire on ecm which is how its been installed. That's about all I can think of. Sorry if I listed a lot but I know details to new eyes is crucial to reach a solution. Thank you for any insight.

Re: code 46 and having rare start after VATS bypass
 

Being the VATS is the likely problem, contact someone like Tunedperformance on the boards and he can eliminate the VATS right in the PROM. That'll skip the unnecessary bypass module. https://www.thirdgen.org/forums/engi...g-memcals.html

Re: code 46 and having rare start after VATS bypass
 

Problem solved. Ordered the Vats bypass from Bakerelectronix.com for 39.99 and had suspicion on its reliability from the beginning. Replaced everything else in VATS circuit before thinking this could be the problem cause the tech at the manufacture said hes made 6,800 over 11 years and never had a module fail while still outputting correct voltage I was getting. Im #1 not working but I do not feel so special because I could have been in my car 2 weeks sooner. Now its working after ordering a $14.99 module on ebay and installing it the same exact way as the old one. engine fired right up and no more engine code. returned the ecm I bought and the old one works still. All I lost is time. Getting a VATS disabled prom is def the way to go but a $14.99 is much cheaper route if it works. Im an Electrical engineer student and just knowing how small IC chips like the one in the VATS frequency generating module can fail DOA was enough to make me suspicious but not having a way to confirm frequency right now made me check other likely causes. Hope this helps the next person doing a VATS involved engine swap. Case closed.