3800 starts, runs for 1-2 seconds, help!

Hopefully someone can help me out, or point me in a good direction to look...

I am about done wiring up a 2003 3800 S/C swap into an 86 fiero. I am attempting to control the engine with a 2003 PCM running the S/C OS. The car has a healthy cam in it, 42lb injectors, N* MAF, N* TB. It cranks, all sensors I can think of seem to read correctly in HP Tuners VCM scanner. However, the danged thing wont run for more than a second. I can crank it over and it fires right up, but then dies within 1-2 seconds. Very frustrating!

To trouble shoot this, I've validated that it has spark. I went so far as to keep the engine running with starting fluid for as long as I wanted, which means it must have spark to keep running.

That led me to thinking its fuel related. I've validated that all 6 injectors are wired from their respective cylinder, to the injector wire # on the PCM. So cylinder 1 has injector 1, cylinder 2 has injector 2, etc. I've hooked up a fuel pressure testing gauge and validated that it has healthy fuel pressure before starting, and when it starts. I think it was 60psi or so? So there's fuel pressure, there's spark, and as far as I know the injectors aren't on the wrong cylinders. Everything I can think of suggests that the PCM is cutting fuel on me.

I am aware of VATS, and as far as I know I've disabled it with HP Tuners. To disable VATS I swapped to PWM, and set P1626, P1629, P1630, P1631 to "No Error Reported". I went so far as to load "VATS Status" in VCM Scanner, and it says "PASS".

I'll be damned if it doesn't behave as if VATS is still turned on though. Reminds me exactly of what my LS swapped car did before I learned about VATS and turned it off.

Anyone have any suggestions? Im about out of ideas on whats wrong

I attached my tune if anyone has any ideas?
Attachment 58060

Have you tried setting it to serial with those DTC's disabled?

Yep, tried that too. I did read someone saying you had to flash entire to get the VATs change to take affect? Is that true? Because I didnt try flash entire when I swapped to serial

Lots of research here has resulted in no one seems to know how to turn VATS off on a bonneville OS. For anyone in the future, beware of this caveat. Looks like I'm going to have to license another OS, sigh

There's a specific thread on how to remove VATS on V6 vehicles, it's a little in depth. Search for it.

Quote:

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Originally Posted by Keith@HPTuners

There's a specific thread on how to remove VATS on V6 vehicles, it's a little in depth. Search for it.

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Hey Keith, I'd ran across the thread. It doesn't work on the bonneville OS. There are a multiple of ways to turn off VATS on the V6's I've found. The thread mentions turning off the VATS related DTCs and switching VATS to PWM. That didnt work. I've also saw where in certain V6 OS's you have to turn the VATS injector seconds to 0 (something that HPT doesn't give access to) to disable VATS. In my case, I was able to get the bin file, tiny tuner, and change the VATS injector seconds to 0, but that too didnt work. I ended up talking with a well known tuner of 3800's and to his knowledge there is no way to turn off VATS on a bonneville OS, with HPT or any other tuner package he has. All of the tricks that he used on grand prix's didnt work.

fuel pump resistor? does it stay running if you floor it

^ You can bypass the resistor by bending over the low speed pin of the fuel pump relay (top right?) to force the pump to run at high speed. It primes on high speed but runs on low speed except a WOT. Your more then likely running off of primed rail pressure.

That only works for 97-00 factory grand prix/regal cars. In 01 they changed to a venturi fuel pump so there is no need for a resistor.



This swap is in a fiero, which likely has a custom fuel system and it's also a 2003 computer/harness.

this is not good news. I am swapping an 03 bonn l67 engine into an 88 5 speed jimmy. have not tried to start it yet due to lack of exhaust.
I am going to use jimmy fuel pump wiring & relay. don't know if this is going to work but may be something for you to try.
use a key on 12v power source to turn on fuel pump relay, eliminate ecm running relay.
LET ME KNOW IF IT WORKS. THANKS

this is off of GM Service Information for 2003 bonn ssei;
Powertrain Control Module (PCM)
The PCM verifies that the password received from the theft deterrent control module via the Class 2 serial data circuit is correct. The theft deterrent control module can learn only one enable password. If the enable password is correct, the PCM enables the starting and fuel delivery systems.

The PCM disables the starting and fuel delivery systems if any of the following conditions occur:

•The enable password is incorrect.
•The system disable password is sent by the theft deterrent control module.
•No passwords are received – there is no communication with the theft deterrent control module.
Important: If the PCM is unable to communicate with the theft deterrent control module (loss of class 2 state of health) after the vehicle has started, the module will consider itself malfunctioning and enter a fail enable state and illuminate the Security Indicator. The vehicle will not stall or stop running. If the PCM is in a fail enable state when the ignition is turned to OFF, it will remain fail enabled until the next time the vehicle is started. If the PCM is fail enabled the theft deterrent system is NOT active and the vehicle will start. The PCM will remain fail enabled until class 2 communication with the theft deterrent control module is restored.

I have also noticed you can make all class 2 codes to "no error reported." May try this and see if it make a difference.

I would try doing a Write Entire just for the sake of troubleshooting. I've seen a car behave like this once when it had a bad main harness, but that's not very often that would happen. If all else has failed, follow the instructions at the bottom of the VATS Disable Writeup which detail exactly what you need to gather before contacting support. There is still a chance the VATS switch in the PCM was even assigned backwards which was the case with some GM V6 vehicles.

hey guys, I ended up having to license a 2003 GTP bin (along with my bonne tune, argh) You can turn off VATS in the GTP tune. It requires changing the VATS injector time (HPT cant do this, but tiny tuner can as well as a few other tuning packages) along with all the other typical stuff mentioned in this thread previously. Good luck!