Ambient Temp question e38/a4

Hello, I have a 2009 Silverado 5.3 LY5, dod delete, dod flow plate, ls6 springs/lifters, 216/220 .560/.560 lsa 114, high pressure melling oil, long tubes/cat delete, heads decked .20 due to overheating and stock injectors cleaned/flowed/balanced.

I thought I was starting to understand the VVE and MAF relations/spark timing etc and then Arizona decided it was done with summer and has dropped 20 degrees. I felt like I was getting close to the +/- 3% over all and now I am back to having misfires codes and deep colors on my data runs. Would it be worthwhile to scrub out the VVE/MAF and start fresh or would the cylinder bias/ECT be a better place to revise? Any help would be appreciated.

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Start with reworking the VVE its a must from my understanding and it will help you work from there. Learn new tricks. Try filtering your data. You could use those runs to lean it out and see what happens.

winter tips

I thought I found a useful link I had read covering season changes and this wasnt it;to be replaced when i find it cause Im going to need it myself

I have to give you this as a lead for filters

https://forum.hptuners.com/showthrea...airflow/page10

Checkout tuning maf and ve at the same time the filters in that post you will need to do such and cringers tutorials and everything everyone says.

And what kind of misfire codes? If its consistent to 1 it needs to be traced down.

The misfire is cylinder 6, I've pulled the plug and traced the wire everything seems fine. It was on after the cam install and went away once I started to work the VVE/MAF and adjust the AFR, I thought it was a result of running lean but I'll look into it more this weekend.

I started down the GMVE process and that's around the time the temp started to drop here, looking at it from an outside point, I think I was just being gunshy/doubting what I was doing.

Second guessing at its finest! Appreciate the response and I'll drive it today and pick up where I left off.

Quote:

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Originally Posted by Azyeti

The misfire is cylinder 6, I've pulled the plug and traced the wire everything seems fine. It was on after the cam install and went away once I started to work the VVE/MAF and adjust the AFR, I thought it was a result of running lean but I'll look into it more this weekend.

Second guessing at its finest! Appreciate the response and I'll drive it today and pick up where I left off.

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Well with the way that VVE table is doing I was quite serious.

Have u put it in SD or MAF only? Seems to be a good way to check where the problem may be. Most likely with the maf and airflow values. How do you know your timing isnt too high?

And I actually downloaded all of your logs gave them a brief look and compared alot of stuff in your tune to a stock 5.3 I found here Nothing looks crazy besides your VVE and I gave you the truth although I dont know much. When I experienced barometric changes driving north my truck was dying because of a hidden misfire. I learned to just update the VVE as everything else should already be correct and then it continued to fight its way through the misfire.

I hope your certain about your misfires...

Wanted to give this guys tune another look this morning. This was a question regarding me looking at the wrong tune as I almost thought your problem was under the vvt but its not.

Misfire diagnostics will be unreliable with a cam like that.

Do you for sure have a miss on cylinder 6? I'd focus on that before looking at the tune.

Quote:

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Originally Posted by Alvin

Misfire diagnostics will be unreliable with a cam like that.

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This is kinda of what I've factored and to clarify, the codes I am getting are the 300 and 306, random and cylinder 6, I glanced over the random misfire before, my bad. I am curious why its focusing on cylinder 6 instead of moving like I've read in other posts but that's my own edification.

I checked everything again this weekend and all things pass the visual inspection. I redid the timing and I was a little light before so changed from 18 to 22/23 as the baseline and kept working the maf/vve through the gmve equation. Only thing I can say is the "misfire" has moved from when the engine/IAT is heat soaked at 115+ to now happening around 12-1600 rpm with steady acceleration. Once cruising it clears out and doesn't maintain the DTC in the drives I've done until yesterday.

I had computer issues on Sunday and the log didn't save the afternoon file but as the ambient temp was at the high 95ish I noticed the "misfire" was occurring more which makes me wonder if I am causing more problems for myself doing morning/afternoon/evening logs and trying to normalize it?

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After having constant misfires yesterday and reading more last night I am looking into desensitizing the misfire table today, I had a hour errand run for work logged but its too large of a file so here's this mornings drive with the tweaks from yesterday's data loaded in.

Thanks Alvin for the misfire idea/comment, I was headed down a rabbit hole I realize today and looking at the age old K.I.S.S. method. :banghead:

So I took the truck in for a transmission issue and had them test all the ignition packs since everything seemed to be working, glad I did cause 2 where bad/not working correctly and one of the wires was separating from the boot... I feel like an idiot but glad to have all the minor hiccups sorted out. Truck seems to be in a completely different world now than what I thought was normal after the cam installation.

Now to acquire new logs with everything working correctly and see if I can get this dialed in.