Sounds like there are a couple guys here experienced in these setups contributing and I don't have much firsthand experience in new-controller-old-engine, but have a couple questions bugging in my mind that seem like they have the potential to be bothersome "behind the scenes". So just kind of posing the questions for discussion purposes and hopefully some may be relevant to help the project. Probably getting the basic timing and steady state fueling will get you in the ballpark, but additional things I question:
- Would calculated/estimated intake valve temp potentially be vastly different in BBC vs. LS? (for OL fueling)
- Can the intake manifold volume, wall wetting, and evaporation characteristics in the 454 intake be modeled in the tune? (for transient fueling)
- Is injector tip to intake valve distance and intake port and combustion chamber geometry/size, different enough that fuel injection timing would be a more significant factor to adjust?
- Are there any areas in the tune where the much higher rotating assembly inertia should be corrected/compensated for? (thinking along the lines of idle adaptives getting out of whack because it takes way longer than the ECM expects to increase/decrease RPM against the inertia)
As a side cautionary note (not totally privy to facts and data here, just theory) knock sensing may be tricky, not sure if the 7.4l vortec sensors play nicely with more aggressive cams/headers or interact with the e38 well(?), or if sensors original to an e38 application can be re-tuned for the BBC characteristics(?) seems like a daunting task, or you may be going by ear anyway.
This is not affecting you at all right now, just my OCD must mention: Didnt dig too deep in, and may be a factory table oddity, but in [ECM] 12625 - ECT Spark Advance Correction Mult. the 194F row has a 3.5x multiplier in it! its multiplying times 0 in the corresponding 12624 base table right now, but just in case you populate the base table with values that multiplier would give you a bit of a timing discontinuity if you cycle in/around that coolant temp range.
Last edited by CaudleDynamicsLLC; 10-14-2022 at 03:29 AM.
A whole bunch of stock tunes are like that in the ECT base/multi tables. That weird row in 12625 even exceeds the max that's supposedly allowed.
I've done SBCs, LT1s (GEN 2), and BBC with LS controllers. The basics come first.. but yeah.. there are issues with tables that you normally don't have to touch. Mainly how much more fuel they require while cold and transient situations while cool. That's why I recommended tuning while fully warmed up since the rest are just adders/subtractors to normal running conditions.Originally Posted by CaudleDynamicsLLC
Side note.. I honestly don't think intake volume does anything. you can swing it wildly and not notice any difference what so ever. I've also noticed the exact same engines coming with vastly different intake volume numbers.
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Thank you. Will also take more logs trying to log anything torque management related and see where I can get it.
Knock sensors used are ls3 and seem to pick up knock reasonably well. Tested around with timing a bit. There are a bit of oddities in there because coil packs are from ls1/ls6. Motor is internally balanced. Some of the hard to get right things off idle are also partially due to heavy weight of the vehicle, 33" tire and 3.73 gears. Fueling between cold start up and warm up if off, but now going to focus on warmed up region. Some of the changes that I have done so far did help with cold start.
I?ve been running open loop, will not disabling the cat test cause any issues? Just using a wideband now, no stock O2s. I haven?t noticed anything to indicate that the test ever runs anymore even though I don?t have an older editor version where I can disable that. No MIL.
Edit: sorry, I just realized there is a second page to this thread, didn’t mean to jump in this far down like this.
Last edited by Tunercharged; 10-14-2022 at 08:53 PM. Reason: Forgot word
2017 Silverado 3500HD WT 6.0 flex fuel 6L90 6800lbs E78 T43
--- What am I doing??? Why did I do that???---
I don't know this for sure, but logically I'd assume all that stuff is put on hold when in open loop, since it's looking for O2 deviation from normal and in OL it doesn't have a baseline to use as reference.
It seems that way, makes sense.
2017 Silverado 3500HD WT 6.0 flex fuel 6L90 6800lbs E78 T43
--- What am I doing??? Why did I do that???
I had a very clear power reduction right around 194* and thought that table was an issue at first. I had tried 0 on all of those and it made no difference. As others mentioned, turned out it does not get used. Working around the tune in general 194F region is now not an instant no power any more.
Went for another run and caught it acting while logging. Torque management kicking in wildly and randomly. Shows transmission torque management requested. Trying to go through the tune again to figure out why.
Last edited by yevgenievich; 10-15-2022 at 06:25 PM.
When I open that tab, I do not see these?? I'm on 4.10.7 and have the advanced view selected. What's different about yours?
4.8.7 was the last version before those were removed.
Well crap. I guess I need to find somebody with that version or older to go backwards, and keep this laptop there... buy an MPVI3 and another laptop. This is a croc
I have few older versions now including 4.6, but not 4.8. Was going to try and find 4.8.7 as well
On another note, I keep getting these two codes:
0x7E8: P1174 - Fuel Trim Cylinder Imbalance - B1
0x7E8: P1175 - Fuel Trim Cylinder Imbalance - B2
Which makes me think I might still have a vac leak somewhere
I believe at least the random torque management is resolved. Set the abuse mode table to all 1's, and active time for it to 0.1s. That seem to have cured random torque management killing spark advance. Interestingly some other things in the tune finally started to work as well. I had tcc lock up set to engage at 55mph, but it would still kick in around 45mph. Until now, with those tables populated lock up engages at 55mph. Shift points all went up as well.
Have done a number of updates from last year. Intake actually ended up being changed out, but was not that much of a difference with that change until started playing with the tune again. Felt that it did gain rpm with intake change. I still had P1174 code coming in that I could not trace down, and interestingly the couple of days when towing a trailer it did not show up. I am trying to find on how to adjust temperature dependent variables as it feels like it has large swings in fuel trims with temperature changes. Have an idle hunt with ac on and a lean bleep on sudden throttle application that have been trying to identify on how to adjust. Attached current tune for reference.97_burb_e38_t42.hpt
If anyone have any advise, I am still consistently getting P1174 - Fuel Trim Cylinder Imbalance - B1. Except when towing a trailer, then it seems to stay off.
So far tried the following:
Actually swapped intake manifolds was the first thing tried
Two different intake gasket sets(currently on thicker intake gasket set)
Swapped o2 sensors side to side
Swapped injectors side to side
Adjusted valve lash(engine running method)
Capped off pcv system from the intake
Still coming up with B1 cylinder imbalance. Does anyone know what ecu checks to determine the code?
Without the log file showing it doing the thing it will forever remain a mystery.
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