Bowtie Brody's Namesake 96 454

[Mangonesailor]

Pulled data logs, tried to spin tires from every stop for scientific reasons.
Big thanks to @Mangonesailor for helping me get my truck figured out.

If anyone wants to chime in, looking at his logs, when he misfires his driver's side of the engine is running rich. So whatever it is, is on that side. When he does it, there is also little demand for fuel as his throttle position is nearly steady state at various positions.

I think it's either an injector sticking and not spraying fully, intake leak, or maybe an electrical issue with an injector connector or pin.

 

[JWOK]

I found an 8.25 on East Coast Gear; I can't find it now but I checked fitment and it said it fit in a Chevy. There's a couple H2s sitting in the weeds around here, I might knock on some doors and ask about some parts.

I'm planning on a TrueTrac for the rear when I regear everything, mainly I wanted a front locker for when I get in sticky situations and need to crawl out of somewhere.

I went through this myself several years ago and turned out the only lockers that had been made for the 8.25 were discontinued long ago. I found a few listings like you say, but they all turned out to be old pages and no longer available. I don't recall the details on the H2. I ended up swapping in a 9.25 so I can install an ARB. I have the ARB sitting in my garage and one of these days I will get around to starting a build thread to detail all this.

 

[Mangonesailor]

https://forum.hptuners.com/showthread.php?62850-0411-swap-HPT-CASE-relearn-not-working

 

[Christian Steffen]

https://forum.hptuners.com/showthread.php?62850-0411-swap-HPT-CASE-relearn-not-working

You think a case relearn would fix his misfire?

@BNielsen already did injectors right? A bad plug wire, rotor going bad, something spark related seems more likely on an intermittent misfire in my opinion.

 

[Mangonesailor]

But Christian, he has a bank running rich. I guess a weak spark on a cylinder would cause a lean condition?

And I don't want him to do a case relearn to fix it, it's that it will not show which cylinders are misfiring until it's done.

That'd narrow it down significantly.

 

[Christian Steffen]

But Christian, he has a bank running rich. I guess a weak spark on a cylinder would cause a lean condition?

And I don't want him to do a case relearn to fix it, it's that it will not show which cylinders are misfiring until it's done.

That'd narrow it down significantly.

Ah sorry, I should have read more closely. Knowing which cylinder is doing it would help a lot.

Could still be something simple like a crack in a spark plug boot. @BNielsen could also pull plugs and look for the one that is fouled.

 

[BNielsen]

Ah sorry, I should have read more closely. Knowing which cylinder is doing it would help a lot.

Could still be something simple like a crack in a spark plug boot. @BNielsen could also pull plugs and look for the one that is fouled.

I checked the boots and plug wires, and while that seems like a good place to start; it only starts to misfire after about 40 minutes or so of driving after everything's heated up. And it seems to get worse after every stop where the truck just sits and idles for a few minutes.

But Christian, he has a bank running rich. I guess a weak spark on a cylinder would cause a lean condition?

And I don't want him to do a case relearn to fix it, it's that it will not show which cylinders are misfiring until it's done.

That'd narrow it down significantly.

If I'm reading the HPTuners page correctly, I need to snap it up to redline and let off, or I'll snap the throttle to a certain point and then the PCM will command fuel cut-off? I know you modded the tune to lower redline due to Lextech's being set at 6K? It won't hurt anything doing the relearn will it?
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Anyone else think their truck acts up on purpose sometimes? Not only am I battling the running hot/misfire issue, on a short drive to grab lunch today my oil pressure gauge decided to not work correctly.
It pegs out under throttle to where it's trying to wrap around, but under deceleration or when the RPMs are going down it begins to read correctly. So, I guess it's time to send out my 110 speedo to get rebuilt and get that swapped in.

 

[Mangonesailor]

If I'm reading the HPTuners page correctly, I need to snap it up to redline and let off, or I'll snap the throttle to a certain point and then the PCM will command fuel cut-off? I know you modded the tune to lower redline due to Lextech's being set at 6K? It won't hurt anything doing the relearn will it?

It'll be fine at the rpm with no load, the ECU will kill the fuel before 5600rpm.

And no, you just floor it and the ECU will kill fuel. The IAC will open enough to keep the engine running once it gets near idle speed but like I said, when it get to near idle, let off the gas and then shut the engine off.

Or have your snap-on scanner guy try again. Like I said those rev limiters were my issue. If the rev limiters are set too low it'll bounce off them for nearly an eternity (trust me, I listened to the guy try it 20x or so and it wouldn't take). With the rev limit raise the engine will bbrbbrbbrbbrbrrrRRRRAAAAGGGHHHH pahhhhhhhhhhhhh right to redline and to idle on its own.

 

[BNielsen]

It'll be fine at the rpm with no load, the ECU will kill the fuel before 5600rpm.

And no, you just floor it and the ECU will kill fuel. The IAC will open enough to keep the engine running once it gets near idle speed but like I said, when it get to near idle, let off the gas and then shut the engine off.

Or have your snap-on scanner guy try again. Like I said those rev limiters were my issue. If the rev limiters are set too low it'll bounce off them for nearly an eternity (trust me, I listened to the guy try it 20x or so and it wouldn't take). With the rev limit raise the engine will bbrbbrbbrbbrbrrrRRRRAAAAGGGHHHH pahhhhhhhhhhhhh right to redline and to idle on its own.

I might try it once or twice, we just had new neighbors move in to my neighborhood and between my brother's straight piped 24V Cummins, Dad's LB7, and other high RPM shenanigans I'm trying to be mildly considerate

 

[Mangonesailor]

I might try it once or twice, we just had new neighbors move in to my neighborhood and between my brother's straight piped 24V Cummins, Dad's LB7, and other high RPM shenanigans I'm trying to be mildly considerate

Oh, what I usually do is go to the local grocery, drive around back with my pipes facing the woods and do stuff like that.

Same when I was tuning my old sound system. Just did it in a parking lot somewhere.