89 Firebird Turbo 3500 Build

[TGP37]

Isn't there a diode on one side of the coil? I believe there is.

Even though it appears the same spark on 5 and 2, one is flowing towards the coil and the other is flowing away. I really can't be sure if the coils you/we use have such a diode. I don't see why not, the current is always going to flow one direction opposed to the trigger current discharging. And I know the ICM circuits don't flip the current back and forth......



This might have something to do with this quagmire spark thing. Maybe a ground loop is occuring somewhere. They can be known to cause some funky issues in electronics.

[robertisaar]

i don't think there is a diode in the GM DIS coilpacks... i've never tested it as such though.

[TGP37]

I never thought much about this until now, strange to think our plugs fire in opposite polarity. At least as far as I can tell (in theory) they do.

Hope you figure this out caffeine.

[robertisaar]

they indeed fire that way. a lot of Fords did as well, they kind of ghetto'd it though... once they started using platinum plugs, they only put the platinum on one side... on one bank it was on the ground strap, on the other, it was on the center electrode... had to do with the direction the current flowed, but i can't remember which. GM just put it on both sides.

[pocket-rocket]

That would have someone heck of a diode to stand that kind of energy.

Easy enough to check. Resistance test the towers both ways. If you only get a reading one way there is a diode, get a reading both ways and there is no diode.

I've never bothered with polarity with coils, so I would imagine there is no diode.

Sent from my HTC One X using Tapatalk 2

[caffeine]

Well I swapped out the spark plugs with NGK tr55s and #5 now seems to spark consistently. However, it runs great when cold but once starting to warm up it will sputter and stall. What could cause this?

[robertisaar]

is it acting up when it drops into closed loop?

[caffeine]

Closed loop is disabled for now

[robertisaar]

got a log of it happening?

[caffeine]

I will

[caffeine]

LX9 Bins.zip

Here are a couple bins I tried today and a few logs as well. I also included a modified adx that shows what my wideband is reading.

When the motor stalls, it seems to stall like the key was turned off. Sometimes it's idling fine and then with no warning just stalls. I'm still pretty convinced it's spark related because when the exhaust pops the wideband dips lean, then rich, then back to normal.

Here's a video that shows how the exhaust pops.
http://www.youtube.com/watch?v=IdoJXFJAAHQ

Also keep in mind there's been no boost yet.

[TGP37]

[ATTACH]7315[/ATTACH]

Here are a couple bins I tried today and a few logs as well. I also included a modified adx that shows what my wideband is reading.

When the motor stalls, it seems to stall like the key was turned off. Sometimes it's idling fine and then with no warning just stalls. I'm still pretty convinced it's spark related because when the exhaust pops the wideband dips lean, then rich, then back to normal.

Here's a video that shows how the exhaust pops.

http://www.youtube.com/watch?v=IdoJXFJAAHQ

Also keep in mind there's been no boost yet.

Tiny Tuner and HP Tuner can not open the PCM files, corrupted.

I would consider the PCM tunes as the problem at this time. It would make sense why it is restricted to cyl#5 and swapping coils, plugs, cables, ICM, etc.

Did you flash a different file to the PCM other then the original file? Or the PCM has a damaged component.



I didn't view the logs.



Rob and PRocket, I bet the platinum on one side of the spark plug might be the reason why our motors do not like some plugs, ie bosch. Half of the plugs will fail early.

[pocket-rocket]

Tiny Tuner and HP Tuner can not open the PCM files, corrupted.

He's running nAst1, so he's on OBD1.

Sent from my HTC One X using Tapatalk 2

[TGP37]

He's running nAst1, so he's on OBD1.

Sent from my HTC One X using Tapatalk 2

lol, duh, I knew that. A little early in the morning for me I guess.


That's what happens when ALL my experience is OBD2 based. I never messed with OBD1. Though I considered it once for the turbo.

[pocket-rocket]

lol, duh, I knew that. A little early in the morning for me I guess.

I had been up for just over 4 hours at that point, lol. Posted that at break time half way through my work day