Error in my tune-$100 to find it for someone

[67SS509]

I have tried jumper wires from the battery cable directly to pink supply wires to the coils and the injectors. Have also jumpered the ignition. But remember this is a brand new stand alone harness also.
On my dashboard I always log voltage so it's in the PID's if you want to have a look at it. Went thru 3 alts. to get one that maitained 14+ volts.

I think this one is going to make us all smarter when it's fixed. I have learned 2 times more than I thought I knew.............

[LS1_Dragster]

The way I see it, since you shortened up the gap and it runs better then that clearly indicates there is not enough voltage to jump the gap.

So what effects that?

1) Voltage and AMP'S to the coils
2) Volts/amps to the plugs
3) How long the coils are saturated

There may be more factors that I don't know about.....

[67SS509]

The Snap-On measured the dwell at 34* if I was reading it correctly. That should enough I think.
I agree that we have narrowed it down to weak voltage.

[5.7ute]

The collapsing of the field is just as important as the input voltage to get a strong spark. For a quick, cheap test I would be adding a few extra earths to the system.

[joecar]

Do you have an amp clamp probe for the Snap-On...? If you do, pick a coil and clamp the probe around the power wire for that coil, and capture the coil current... and also capture the secondary voltage from that same coil capacitive probe)... your Snap-On is dual channel, right...

The current waveform has to have a specific shape if the coil is charging right;
the secondary firing spike indicates how much energy is being demanded to jump the gap (the lower the spike the easier it is to jump the gap).

What is the dwell time in ms...? What is the spark duration in ms...? The Snap-On has on-screen cursors, use those to make measurements. Post some screenshots from the Snap-On. Does the Snap-On have a save-to-PC-via-USB feature...?

[swingtan]

I dont believe it's going into protection mode, the assumption was because it was 24 degrees at WOT. He installed my tune and it changed to 27 degrees where I have it plus in my tune it's 10 degrees in protection mode.

Lee

Cool, I'd missed that.

Now to find the root of the spark issue.....

[67SS509]

Do you have an amp clamp probe for the Snap-On...? If you do, pick a coil and clamp the probe around the power wire for that coil, and capture the coil current... and also capture the secondary voltage from that same coil capacitive probe)... your Snap-On is dual channel, right...

The current waveform has to have a specific shape if the coil is charging right;
the secondary firing spike indicates how much energy is being demanded to jump the gap (the lower the spike the easier it is to jump the gap).

What is the dwell time in ms...? What is the spark duration in ms...? The Snap-On has on-screen cursors, use those to make measurements. Post some screenshots from the Snap-On. Does the Snap-On have a save-to-PC-via-USB feature...?

Yes, it does have a amp clamp-on but it is not a dual trace. I played with this some today before reading your post here so I don't have specific numbers to your answers. What I did not knowing the values to be looking for was to compare the peaks and duration to my stock 05 Chevy truck. Instead of using the cursor I just turned the grid on for measurement. They both looked the same. This unit is 10+ years old and only has the capability to freeze and send to a printer. I'll try it again tomorrow and post some shots.

I have reviewed all the grounds and feeds again today.
-positive and negative cables are from battery to motor, pcm, accessories and starter with 3 large grounds from motor to body. Also a large cable from battery to body. All grounds from PCM and coils are lugged to front of motor for easy verification. Voltage to injectors and coils are from a relay that is fed directly from battery cable. This relay is triggered with ignition key. There is absolutely no low voltage or ground problem. I have ohmned every connection. Problem has to be one of the following:

1-software related (tune)
2-drivers in the pcm (this is 3rd pcm)
3-coils or plug wires (this is second set)
4-plugs (this is 3rd set)

I think one of my next steps is to ohmn the plug wires.

[joecar]

When you ohm the plug wires, flex them around while ohming (I'm sure you know that already...).

[LS1_Dragster]

I'm thinking your relay is fluttering when under load, replace the relay or come directly off your keyed ignition. Maybe even a bad ground to the relay.

Lee

[98 tigershark]

The map sensor position had to be changed too. Look at that as well. It can change things, I would call GM Performance, really.
With the 06ZO6+ Look at B2103, 2105 and finally look at the B1555 and B5113, 5112 as it shows that map affects spark. Or the VE table G/S is affected by MAP in older systems 99-04. The map sensor position has had to change even if only a little and may need adjustments for that manifold. Look at the map setting in the Diagnostics as I am almost sure that G/S is affected by Map.
Best wishes,
98 tigershark

Made another change today and seen a major improvement. I would say problem is solved but I did hear one high rpm miss. I closed the gap on the plugs from .030" to .024". I got to thinking maybe it was blowing the spark out. I know this is a non boosted engine but the heads do flow close to 400cfm. For the record plugs are NGK heat range 7. Ran it up to 6500 in high gear and it felt strong. Couldn't make anymore runs today because rain set in. I don't really understand why the improvement because I have ran this plug at the .030" gap for over 2 years. The only change is the carb style intake versus the stock LS7 intake and 48lb injectors versus 42lb.

I think I'm going to try a "cut back style" plug next. This thing is set up for a 400hp shot of nitrous so this might be needed anyway.