LS3 runs for a second then stops.

[Drews Cruise]

Hey all.

I have a 2013 Corvette LS3 and I'm using a Wiring Specialties harness. Plugging it all up into a BMW e46 chassis. I'm running the stock fuel pump from the E46 and I have that hooked up to fuel rail. There is a return line and I just left that as is for a test start of the engine.

I have 3 grounds on harness hooked up near cylinder heads on back of engine. Alternator is connected to harness as well as directly to starter. The battery + is connected to starter and battery - is grounded to back of cylinder head along with one of the harness grounds. MAF is connected to harness and sitting on side of chassis. The engine does not currently have the serpentine belt or ac belt on it for this test run. O2 Sensors are also not connected.

I tried to start it with the BMW gas pedal and then the Corvette gas pedal and while the pedal is registering in VCM Scanner, there is no change in the result.

What's happening is I turn the key, the engine turns over and then dies after about a half second. I have confirmed that VATS is deleted. I also tried to toggle VATS delete and it wouldn't let me add VATS back.

Please see attached log for more info. I really want to get this thing running so I can finish buttoning everything up!

I'm so ready to get this thing running!

GMW E46 First Start Attempt.hpl

[blindsquirrel]

Does the BMW fuel tank module have an internal fuel pressure regulator in it? If not, your rail pressure is way way too high, possibly +100psi.

[Camaro6]

Why is your speed 158mph during crank? Is the tune set for higher than 158mph? It's wrong either way, but could be why its shutting off. You should be logging rpm and many other items to know what's going on.

[blindsquirrel]

Auto trans ECM OS with no TCM. Off to a great start.

screenshot.23-04-2023 22.45.41.png

[blindsquirrel]

Did you crank it during that logfile? Why is RPM = 0?

[marksawatsky]

I just had same problem with LS7 from 2006 Vette. The fix was to do a complete write when uploading the VATS delete tune.

[Alvin]

Hey all.

I have a 2013 Corvette LS3 and I'm using a Wiring Specialties harness. Plugging it all up into a BMW e46 chassis. I'm running the stock fuel pump from the E46 and I have that hooked up to fuel rail. There is a return line and I just left that as is for a test start of the engine.

I have 3 grounds on harness hooked up near cylinder heads on back of engine. Alternator is connected to harness as well as directly to starter. The battery + is connected to starter and battery - is grounded to back of cylinder head along with one of the harness grounds. MAF is connected to harness and sitting on side of chassis. The engine does not currently have the serpentine belt or ac belt on it for this test run. O2 Sensors are also not connected.

I tried to start it with the BMW gas pedal and then the Corvette gas pedal and while the pedal is registering in VCM Scanner, there is no change in the result.

What's happening is I turn the key, the engine turns over and then dies after about a half second. I have confirmed that VATS is deleted. I also tried to toggle VATS delete and it wouldn't let me add VATS back.

Please see attached log for more info. I really want to get this thing running so I can finish buttoning everything up!

I'm so ready to get this thing running!

GMW E46 First Start Attempt.hpl

The log had these codes.. Albeit permanent..so I don't know if they are still a issue.. but this would cause this type of situation.

P2122 - Throttle/Pedal Position Sensor/Switch "D" Circuit Low (Permanent)
P2127 - Throttle/Pedal Position Sensor/Switch "E" Circuit Low (Permanent)

[Drews Cruise]

Why is your speed 158mph during crank? Is the tune set for higher than 158mph? It's wrong either way, but could be why its shutting off. You should be logging rpm and many other items to know what's going on.

Might be an issue with a module on the harness cause you're right, the speed isn't registering.

Did you crank it during that logfile? Why is RPM = 0?

Yes I did. I haven't gotten any RPM readings. I contacted Wiring Specialties several weeks ago about this and they said they wouldn't provide support unless I bought one of their flashed ECUs. Worst case, I'll buy a flashed one from them to get support and then have two ECUs...1 to tinker with, the other for daily driving. Best case, I'll ask for their tune and they'll email it to me.

I just had same problem with LS7 from 2006 Vette. The fix was to do a complete write when uploading the VATS delete tune.

Thank you for your comment. I just tried this. The engine seemed to light up a little bit but it still stops.

The log had these codes.. Albeit permanent..so I don't know if they are still a issue.. but this would cause this type of situation.

P2122 - Throttle/Pedal Position Sensor/Switch "D" Circuit Low (Permanent)
P2127 - Throttle/Pedal Position Sensor/Switch "E" Circuit Low (Permanent)

Any idea on fix? I wonder if I could calibrate (if that's even possible). I used E46 pedal then switched to Corvette pedal if that matters. Same result with both.

Here's the Engine Start Attempt Feb24.hpl of my latest try... I flashed the tune for a 2013 Manual Corvette Tune. Also disabled "Starter Fault Checks", and maxed out values to disable CFCO (pic below). Additional files

Capture.PNG
Capture2.PNG


Thoughts on next things to try? I feel like I'm getting closer! It seemed to run a bit longer this time. Maybe 1.5 second instead of just .5.

[blindsquirrel]

You still have no RPM signal.

Why does voltage drop from 11.78 to 0.72?

[blindsquirrel]

Does the BMW fuel tank module have an internal fuel pressure regulator in it? If not, your rail pressure is way way too high, possibly +100psi.

[Drews Cruise]

There is an external fuel pressure regulator on the E46. It should be running at around 50psi.