Getting my rear handed to me trying to figure this out. It seems all the usual tactics aren't working. I've adjusted throttle cracker/follower, base airflow, ve, spark, nothing seems to help. The engine is a gen4 LH6 that I have deleted AFM and installed the BTR low lift truck cam, LS1 intake and dbc TB, being controlled by a 411. I'm looking for some guidance.
Final Tune.hpt
IdleDip.hpl
IdleDip.Charts.xml
IdleDip.Channels.xml
Last edited by apd855; 10-08-2018 at 06:27 PM.
Try getting the overall airflow model dialed in. The tune is lean all over the place.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
New to the tuning game, obviously. Graphed the VE and MAF based off STFT's copy and pasting %half over multiple drives. Also performed an idle air scan. Thought I had things close, apparently not. How should I proceed.
If you did much of that tuning with intake air temps way up in the 150-160 range, you data is kinda crap.
You need to figure out a better intake setup so the air temps aren't so crazy high.
Also a wideband makes fuel tuning way easier that short term trims.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
That log was made in desperation, just buzzing around the block. I was keeping an eye on my iat while logging, and they were running around 80 degrees.
Correct on the intake. Engine is wedged into a 90 300zx. Going to take the winter to come up with something different. Was hoping to resolve the idle issue before the snow flies.
I see your in Rogers, wish you were closer than 4 hours. At this point I would gladly compensate you for your time.
I'm still green in some areas but one that kicked my ass was idle. Let me pass on to you what I learned.
first, and most important. Your ve table must be correct. log your idle. pay attention to your idle cells (map kpa or gs and rpm) take note of those. then look in you tune and see how much difference the cells are adjacent and if it as big jump then you need to faniggle the area to be smoother. I bit jump is 10 number in adjacent cells, bring that down.
SAME THING IN YOUR TIMING TABLES.
make sure your tps is reading zero.
log and get your idle air correct. your idle air being off will cause it to die. Running airflow as they call it.
heres a method i use once those things are close: start scanner. engine running. logging your trims. use the scanner to force the idle lower by 50 rpm. let it log a bit. keep going down until it wont idle anymore. now crank it back up. do the opposite, bring it up 50 rpm at a time until you get to 1200. got your data...copy paste it. flash it. now, lets do the same thing except we not worried about the fuel trims. if you can make it die, the throttle blad needs to be cracked open some. do that. reset the tps. start over. Shoot for 100-150 or so rpms below your target idle that you can bring it down. example, say you idle at 700....you bring it down with the iac to a minimum of 550-600 rpm before the iac wont bring it down anymore. why? because you should not be able to kill it with the iac motor.
Are you using a stock throttle body? if not then you need to more your IAC effective table over to the right by one space.
2004 5.7 gto
7875 turbo
Heads/cam
Yes, its a stock throttle body. In the last paragraph, you say to log trims, and cut and paste. Where are you pasting the fuel trim info? On my wide band i notice the engine goes rich during the dip, leans out as it recovers.
Something else I have noticed is that the dip/die doesn't happen until i come to a complete stop. Ill watch the scanner and everything seems to be on track for a smooth return to idle, but the second I stop, the dip hits. I adjusted the follower decay rate to where it takes about 5 seconds to decay out, then I can come to a stop without it dipping, but as soon as the follower decays, i get the dip. Seems like the transition to idle, there is a large transition in one of my tables, spark, ve, etc. I just cant find where it might be.
Last edited by apd855; 10-10-2018 at 09:50 AM.
I’m not sure what you know and what you don’t. I’m assuming you know how to log your stft or ltft (short term or long term fuel trims). You copy the chart (histogram) in your scanner. Then you go to paste in your tune to your ve table but when you click on paste, you’ll see it says “paste special” and do it in half %.Originally Posted by apd855
2004 5.7 gto
7875 turbo
Heads/cam
Yes, I have performed that over multiple drives. That is how my VE table got to where it is.
Is your ve and timing tables smooth? no spikes? no adjacent numbers next to each other with large differences? (10 or more)
is your running airflow correct? did you log it? create a histogram with temperature across the top, desired air flow cells below it. you can copy the temp labels from your tune and paste them in your histogram chart. crank the vehicle when cold, let it idle to operating temp in neutral and then do the same thing the next day in gear if you have an auto. you can get it close by putting what you logged in neutral in both the neutral and drive cells and then highlight all the drive cells and add a little to it.
2004 5.7 gto
7875 turbo
Heads/cam
I've done ve, maf, and idle air. Those tables are set per the error histograms.
Did you do everything thing else i posted? is your timing jumping? whats the timing do when coming to a stop? what about the fueling? is it going rich or lean? Whats your idle air flow trims doing?
Last edited by KFXGUY; 10-10-2018 at 02:10 PM.
2004 5.7 gto
7875 turbo
Heads/cam
At idle my timing is jumping +- 7?. When coming to a stop my timing pretty much stays steady. In my spark tables i have the 400 set to 45? and 600 to 36? in the idle area trying to catch the dip. Coming to a stop timing advances acordingly. The further it drops the more advanced it goes. During the dip my wideband drops into the high 11s to low 12s.
There is a point of diminishing returns when it comes to adding idle timing... I would try adding more idle air (maybe through cracker or other off idle air adders) and rely less on trying to add a ton of timing. What is the IAC doing when coasting down and at idle? I don't have tuning laptop on me so I can't check the file or logs.
JTC Performance - Authorized HP Tuners Reseller
Remote performance tuning
Something that maybe someone can answer for me. I am running a manual 5 speed with no input to the pcm for brake or clutch. Do the P/N tables have any bearing. I am logging tranny gear in my scanner and it always shows 2nd.
Notice the factory table has less timing in the lower rpm range and the area where your idle would drop? Yea, there’s a reason for that. MORE timing at that low of an rpm makes LESS power. Try mimicking the factory tables. I’d personally copy paste the stock tables and add 3-5 degrees to each while table. And go from there. I tried the more ting to catch the dip, don’t work. Makes it worse.
2004 5.7 gto
7875 turbo
Heads/cam
One more strange issue I have. In the editor, when I set the transmission type to manual and PRND to none and write the tune to the car, it will only rev to about 1500 rpms. There seems to be some type of limiter or fuel/spark cut off. Anyone else experienced this?.
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