2004 6.0 NV4500 Tahoe

[iamdub]

I summed it up to just a cammed cold start and not cats like all the cool kids make videos of.

It was cool in 2020.

 

[iamdub]

I will probably end up putting on .051 gaskets to get close to 10.5cr in case I miraculously find some sort of Wuhan whirly boy to force-feed this thing.

Other good/bad news is that my low oil pressure on cold start issue seems to have eliminated itself and I think it was caused by a severe misfire which I recently solved with the new plug wires. The truck has not only started up with 40psi every morning but it doesn't act funny and buck/surge like it used to either. the bad news part of this is that I beta my head against my laptop for close to a year trying to solve the weird startup condition that I was convinced was tunes related. I think the entire time it had a severe misfire. Another reason I think this, is that when I did the plug wires the other day I was being bothered by a neighbor talking to me the entire time and I actually started the truck with 2 wires disconnected from the plugs #4/#6. The truck started up fine and I wouldn't have noticed there was an issue except I did a visual inspection before I closed the hood and saw them. My point is that these trucks will run remarkably well even down on cylinders.

Do you know if you can "tune out" misfire sensitivity? I scanned mine the other day and had 0 misfires throughout about 20 minutes of driving- cruising, WOT, 0-100+, etc. I just thought these things practically had built-in misfires.

 

[pwtr02ss]

Do you know if you can "tune out" misfire sensitivity? I scanned mine the other day and had 0 misfires throughout about 20 minutes of driving- cruising, WOT, 0-100+, etc. I just thought these things practically had built-in misfires.

You have to tune that out for your stall or it throws the cel. I think I did below a certain rpm. I can't remember the exact number

 

[iamdub]

You have to tune that out for your stall or it throws the cel. I think I did below a certain rpm. I can't remember the exact number

Interesting. Well, I gave it all sorts of RPM and throttle inputs. I hope it's not tuned out that much. Do you know where I'd find this info?

 

[Tonyrodz]

Interesting. Well, I gave it all sorts of RPM and throttle inputs. I hope it's not tuned out that much. Do you know where I'd find this info?

Why wouldn't you want to tune out alot of misfires? You'd want that in there?

 

[iamdub]

Why wouldn't you want to tune out alot of misfires? You'd want that in there?

Well, I don't mean so much as tuning them out. I meant dumbing down the crank and/or cam sensor(s) so they're not detected.

I guess it's not so important as someone excessively dumbing down the knock sensors. Like I said, I thought a misfire (at least a detected one even if it's not actual) here or there was just part of normal operation for these. When I saw all zeros, my first thought was that something wasn't right, and could those sensors be so desensitized that they're missing some things they shouldn't be.

 

[Rocket Man]

Well, I don't mean so much as tuning them out. I meant dumbing down the crank and/or cam sensor(s) so they're not detected.

I guess it's not so important as someone excessively dumbing down the knock sensors. Like I said, I thought a misfire (at least a detected one even if it's not actual) here or there was just part of normal operation for these. When I saw all zeros, my first thought was that something wasn't right, and could those sensors be so desensitized that they're missing some things they shouldn't be.

That’s what I thought as well. When @Tonyrodz said a few days ago he had zero misfires I thought something was wrong. And on top of that it wasn’t running good which seemed even stranger.

 

[randeez]

if its not firing at all, it cant be misfiring

 

[iamdub]

if its not firing at all, it cant be misfiring

 

[Dantheman1540]

Ok I definitely want to look into desensitizing the misfire readings because it seems to be BS IMO. I think before the weird startup driveability problems maybe have been a bad plug wire because that’s totally gone *knocks on wood*. The 4k Misfires has got to be BS since it only happens at idle and the idle feels rock solid.

How do I mess with these tables? Add or subtract? Where? And how much?