No Start After Welding

[SSSTANG]

I did some mods to the rear suspension over the last two weeks. I remembered to disconnect the battery, but not until after running a weld bead. The battery/EFI have been disconnected for two weeks until today. When I tried to start the car, it turned over for a while like it wasn't getting spark, but finally fired up. It stumbled and wouldn't idle because it was pig rich. I thought the tune may have been corrupted so I reloaded the Global File but it didn't solve the problem. Any suggestions of what to try next?

[Danny Cabral]

...but finally fired up. It stumbled and wouldn't idle because it was pig rich.

Check your engine (air, fuel, ignition, valvetrain, oil, WBO2/exhaust systems).

I thought the tune may have been corrupted so I reloaded the Global File but it didn't solve the problem.

If you uploaded a "known to be good" Global File, then the problem isn't in the tune.

[SSSTANG]

Could this be a problem?

[Danny Cabral]

I would replace those spark plugs. All the Cranking Fuel from repeated start attempts may have fuel saturated the spark plugs. If the spark plugs have been fuel saturated, they'll probably need to be replaced.

[SSSTANG]

I put a new set of NGK spark plugs in and it still won't start. I have a spark tester, but don't have anyone to crank it over while I watch tester. It started last night, just wouldn't run right. What about reflashing the ECU firmware?

[Danny Cabral]

I put a new set of NGK spark plugs in and it still won't start.

http://forums.holley.com/showthread....5760#post45760 (Scroll Down To "Typical No-Start Checks".)

I have a spark tester, but don't have anyone to crank it over while I watch tester.

Use a remote starter tool if you're by yourself.
Is the Cranking Timing still synchronized? (Temporarily disconnect fuel injector harness.)

It started last night, just wouldn't run right. What about reflashing the ECU firmware?

Might as try it. Are all your Engine & Ignition Parameters still programmed correctly?

[SSSTANG]

Is the Cranking Timing still synchronized? (Temporarily disconnect fuel injector harness.)

Disconnect fuel injector harness and cycle power, or crank it over or...?

[Danny Cabral]

Disconnect the fuel injector harness and crank the engine over with the key on.
View the Cranking Timing with a good timing light on #1 cylinder.
Is it still set to 15° BTDC (or whatever your Cranking Timing is set to)?

Originally Posted by Danny Cabral Ignition Timing Cylinder Sequence Verification Ensure the Firing Order is entered correctly in Ignition Parameters (System ICF). Before the initial start, disconnect the fuel injector harness and verify at least, the first four cylinders in the firing order using a timing light. If your cylinders are firing in 90° intervals BUT in the wrong sequence, the coil harness is connected wrong (at the ECU or at the coil packs). Hopefully you have a fully degreed balancer or at least markings every 90°: 1st cylinder, in firing order, should fire at 0° (or 15° - add whatever your cranking timing is) 2nd cylinder, in firing order, should fire at 270° (or 285° - cranking timing added) 3rd cylinder, in firing order, should fire at 180° (or 195° - cranking timing added) 4th cylinder, in firing order, should fire at 90° (or 105° - cranking timing added) 5th cylinder, in firing order, should fire at 0° (or 15° - cranking timing added) 6th cylinder, in firing order, should fire at 270° (or 285° - cranking timing added) 7th cylinder, in firing order, should fire at 180° (or 195° - cranking timing added) 8th cylinder, in firing order, should fire at 90° (or 105° - cranking timing added)

[SSSTANG]

I drove the car on Sunday, two weeks ago, then parked it and have not raised the hood until yesterday. So nothing has been changed physically or manually with anything concerning the ECU/engine, since it was last driven.

Reloaded firmware, verified red/white wire has power when cranking, did TPS Autoset, disconnected fuel injector harness, cranked the engine over then reconnected harness. Still won't start. Was able to check spark with the tester and there is no spark. Checked tester on lawn mower and it's good. Injectors are firing one time, when engine starts turning over. Still no spark.

Other things I have verified:
Battery is charged.
TPS Autoset.
Cranking RPM.
Good sensor values.
Keyed +12V when cranking.
Fuel pressure at 42 psi.
Injectors are firing.
Fuel pump primes.
Firing Order is entered correctly.
ECU controls timing and there is no spark.
Ignition Type is entered correctly (GM LSX 58 tooth) I may try CUSTOM, but I don't know OUTPUT SETUP.
Fuel Injector Information is sequential, but will use Bank-To-Bank if I change to Custom Ignition Type.
Air & coolant temperature modifiers are correct.
I have not recorded a Datalog or System Log.
Power is disconnected from ECU tonight.

[Danny Cabral]

I drove the car on Sunday, two weeks ago, then parked it and have not raised the hood until yesterday. So nothing has been changed physically or manually with anything concerning the ECU/engine, since it was last driven.

This is why I stated in post #2, "If you uploaded a "known to be good" Global File, then the problem isn't in the tune." I wouldn't change things in the Global File, since you know it's right. This problem seems engine related (ignition/sensor/wiring).

A common troubleshooting tactic is changing a bunch of Global File parameters in a mistaken attempt to fix a problem. When the problem is found to be engine related, the user doesn't remember every Global File change they made, and now they're stuck trying to correct the tune.

I have not recorded a Datalog or System Log.

Record a System Log and check mark the "Crank" & "Cam" channels. Is the crank or cam sensor signal flatlined?
http://forums.holley.com/showthread....s-amp-Datalogs (Datalog & System Log Information)
Replace the crank & cam sensors. I've dealt with plenty of LSx crank & cam sensor failures from helping others.