Bowtie Brody's Namesake 96 454

BNielsen · Aug 12, 2022

Supercharged111 said:
Noo, I came in here for a small win! How'd you crack it?

I honestly have no idea, I brought them outside and got sidetracked replacing a burnt out cab light; got that replaced only to come back and find it broken.
Maybe I tightened the bezel down too much? Something fell out of my big tree and hit it hard enough??? All I know is I'm pissed about it, I've had these lights for so long now and I was so excited to finally install them

GrimsterGMC · Aug 12, 2022

BNielsen said:
@Supercharged111
Looks like your fancy headlights are going to have a large gap on mine.
Cracked the high beam housing. Guess I'll need to order a new one. Back on the shelf these go, at least for another week or so.

Hi, I was wondering where you got these lights as they have replaceable bulbs and I have been looking for ever to find some for my truck. The sealed beam units are shockingly bad even when wired through relays.

Supercharged111 · Aug 12, 2022

We both got them from LMC Truck.

GrimsterGMC · Aug 12, 2022

Supercharged111 said:
We both got them from LMC Truck.

Thanks

BNielsen · Sep 7, 2022

Ok so as I mentioned in the "What did you do to your GMT400 today" thread, I did an oil change, fuel filter change, and replaced the ICM. I was hoping the ICM was the cause of my misfire, and while I definitely feel like the new part is making a noticeable difference in the driveability, the misfire is still there. The truck actually backfired twice on my drive to meet someone, @Mangonesailor didn't you say you saw something with my trans going nuts or something on HPTuners?
I'm beginning to wonder if the dizzy gear/bearing/something to do with the distributor is worn out, or my coil could be the culprit still? Plugged cats too maybe??
No CEL,

Of course I went on this drive and forgot to bring my laptop to datalog.

Mangonesailor · Sep 8, 2022

Yes, I remember there was something about trans fluid pressure or something that wasn't right.

You need to start data logging trans parameters, and especially engine misfires since now your CASE relearn is done.

BNielsen · Sep 9, 2022

Mangonesailor said:
Yes, I remember there was something about trans fluid pressure or something that wasn't right.

You need to start data logging trans parameters, and especially engine misfires since now your CASE relearn is done.

I went for a drive today and got what I hope is a well-defined data log of the issue; I'll get it sent over, I just hope I have the correct channels selected to highlight the issue. It's not showing any misfire though, and the truck was very clearly misfiring and backfiring.
--------------------------
Made a slight impulse buy, found an air compressor kit on FB Marketplace and shot the guy a message; went and picked it up this evening. Guy said he bought it in 05/06 when he bought a new Duramax but the paperwork is stamped 1997. Only gave 50 bones for it, brand new never installed too!

You must be registered for see images attach

Debating on which truck to install it in, the 454 already has bags but they're Firestone, the 3500 is going to get Pac-Brake bags once it's on the road. Decisions, decisions....

Mangonesailor · Sep 10, 2022

I think Brody has a wire loose somewhere, or a big problem. Here's a screenshot of his log. That white line is the rpm difference between the engine RPM and the trans input shaft. His torque converter had been commanded to lock so it should be 0, but it's 670rpm the whole time. then it starts to oscillate and swing from 0rpm to 1100rpm. That's why it's backfiring. The engine is loading up and suddenly the TCC locks. Spark advance starts going nuts too because of the RPM and probably helps the backfire occur. Maybe the tcc apply/release is too close together but I don't think so because even though its told to apply, its not.

You must be registered for see images attach

I've told brody to go through the tune and keep the tc from locking in 4th gear to see if it changes. If it doesn't, its further back.

Also there's a PWM signal wire that comes from the ECU, I told him to check that.

618 Syndicate · Sep 10, 2022

BNielsen said:
I went for a drive today and got what I hope is a well-defined data log of the issue; I'll get it sent over, I just hope I have the correct channels selected to highlight the issue. It's not showing any misfire though, and the truck was very clearly misfiring and backfiring.
--------------------------
Made a slight impulse buy, found an air compressor kit on FB Marketplace and shot the guy a message; went and picked it up this evening. Guy said he bought it in 05/06 when he bought a new Duramax but the paperwork is stamped 1997. Only gave 50 bones for it, brand new never installed too!

You must be registered for see images attach

Debating on which truck to install it in, the 454 already has bags but they're Firestone, the 3500 is going to get Pac-Brake bags once it's on the road. Decisions, decisions....

Win!!

BNielsen · Sep 10, 2022

Mangonesailor said:
I think Brody has a wire loose somewhere, or a big problem. Here's a screenshot of his log. That white line is the rpm difference between the engine RPM and the trans input shaft. His torque converter had been commanded to lock so it should be 0, but it's 670rpm the whole time. then it starts to oscillate and swing from 0rpm to 1100rpm. That's why it's backfiring. The engine is loading up and suddenly the TCC locks. Spark advance starts going nuts too because of the RPM and probably helps the backfire occur. Maybe the tcc apply/release is too close together but I don't think so because even though its told to apply, its not.

You must be registered for see images attach

I've told brody to go through the tune and keep the tc from locking in 4th gear to see if it changes. If it doesn't, its further back.

Also there's a PWM signal wire that comes from the ECU, I told him to check that.

Thanks for the graph layout; hopefully someone can chime in with a solution. I was kicking around the idea of getting a trans rebuilt and on stand by, I just hope I won't have to have my hand forced so soon!
---------------
I was planning on working on the truck, but heavy rain and with my fiance's grandmother going in the hospital due to dehydration it's looking like this may have to take a backseat for a day or so, I was fixing to go out and flash the truck but we had to go visit her.
Going on a rescue mission tomorrow as well, my sister in law's dad has a 7.3L E350 sitting on a job site dead as a door nail, so hopefully my fix on the trailer will let me get it winched up. Then next weekend I get to pull a parts truck home, so if I can get the PCM flashed I can get a good comparison, and maybe get on course to getting this thing sorted out

Bowtie Brody's Namesake 96 454

BNielsen

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GrimsterGMC

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Supercharged111

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BNielsen

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Mangonesailor

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BNielsen

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618 Syndicate

You won't...

BNielsen

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