There was confusion amongst others about whether the injectors you had were 33lb or 36lb (35), and the answer to which is, yes. They are 33 is it's a 51psi return style '04-down L59, and they are 35lb if it's a '05-up returnless 58psi L59. Then you started arguing that injectors for the same application were different injectors because they had different numbers on them...
I wasn't arguing I was confused too lol. Thanks for that info.Originally Posted by blindsquirrel
Yea keeping track of everything is a pain but it's important lol. Try the injector data from my stock tune and make sure to update the cylinder volume for the displacement change like 5fdp said above and then see what you end up with.
02 Tahoe, Rebuilt 5.3, PRC 2.5 heads, BTR Stg2 V2 cam, 50lb Injectors, Speed Engineering LT's, Offroad Y, Magnaflow catback, Built 4L60, NP241 swap etc etc...
His file already has stock injector data in it the same as any other '04-down L59.
If you compare mine to mjc79's there are some minor differences.
I don't how significant they are but it is what I should be running.
Differences in '02 and '03/'04 are minor, they do show an interesting pattern though... Like, in the Offset table, every cell that's different is different by exactly -0.0153? In the plausibly usable regions anyway.
I'd probably use the more recent data. GM has been known to fix things in later years, while leaving the older calibrations as they were. I think the newer calibrations have more refined data in 'em.
Does this look like any kind of progress?
I updated the injector data, and the cylinder volume. The cylinder volume changed the ve table so I manually changed some high numbers.
Then I did one VE correction and multiplied the error by half. I then did a MAF correction and multiplied the error by one (which I think might have been too much)
I didn't get around to hand smoothing anything yet.
files deleted
Last edited by Jason B; 04-08-2023 at 08:08 AM.
If the engine is near 100% VE or over it will hit 1.00 gm/cyl air mass or more. My 383 SBC gets pretty darn close to 1.00 gm/cyl. If the engine is moving a large amount of airflow it will drive the gm/cyl reading higher. My buddies LQ4 6.0L in his Chevelle is internally stock with some breathing bolt ons and it gets near 0.90 gm/cyl.
My stock internals 5.3 (Gen 4) will do .83-.84 in good air.
Would you say my cyl airmas is normal? I'm at very low altitude if that matters, weather underground says 20 feet elevaton right now.
I did hit 1.00 in one scan file. It runs fine, just a little rich up top, seems to be holding it back from the feel of it.
Almost seems like you need a new tuner if he is leaving you with details he should be dealing with.
For a 6.2L with 226/230 cam at that elevation, probably normal. If it was really happy and tuned well it wouldn't seem odd to be higher than 1.00 g/cyl.
(the factory tune on mine pulled all the timing out starting at .64 - they intentionally neutered the 5.3's so as to make the 6.0L TBSS look better than it really was)
I always tune my own stuff, even the OBD 1 stuff.
My local track closed down for good, a new shop opened up. I took it there hoping the guy could clean up the tune I did but apparently not. I have to street tune it and I usually do some of that on the interstate.
Not the most ideal situation.
I'm not even sure I have a problem. Is a 4 second 0-60 slow or fast in a 4000 pound truck with a stock body, suspension and gears? And 275/60/15 radials. And 0 to 90 in 7.5 to 8 seconds. I'm not sure.
Last edited by Jason B; 04-08-2023 at 08:08 AM.
Hard for me to see if its been mentioned before.. but if cylinder airmass is too high it's typically because the fueling isn't correct. Either low on fuel pressure, rich, or incorrect injector data. 1 g/cyl is a hard number to hit NA. This setup would not do that.
Tuner at PCMofnc.com
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Yes, it is too rich. Once it hits the lower 12's and goes into the 11's the airmass goes from .9's to 1.0.
Seems like I can get the rest of the tune dialed in pretty good except for the WOT PE.
The injector data is not wrong unless GM made it wrong from the factory.
That ratio of how rich it is is about the ratio of how far off the g/cyc is.. The airflow model is off.
Tuner at PCMofnc.com
Email tuning!!!, Mail order, Dyno tuning, Performance Parts, Electric Fan Kits, 4l80e swap harnesses, 6l80 -> 4l80e conversion harnesses, Installs
So thats the VE and/or the MAF airflow?
It seems the VE is a lot easier to get right than the MAF. When I tune the MAF it seems like it doesn't make much of a difference. Like I can tune the MAF error, multiply it by half and paste and it's still off.
I have a feeling it might be the 20 degree bend in the air intake between the engine and MAF. The maf is connected right to the end of this bend.
This is the maf. Fits perfect but I'm not so sure the bend is ideal for function. Could this have something to do with the problem?
This is a new filter, with the smaller filter I had on it I took it off one time and ran it hard and the cyl airmass only went to mid-high .80's
Last edited by Jason B; 04-08-2023 at 08:09 AM.
Being right in front of a bend and being right behind the filter is far from ideal. It also looks like the tube is also maybe oversized which will cause a weak maf signal at lower throttle. Add in what looks like a diameter change in the same area and you have the recipe for a bad maf reading.
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