http://www.hptuners.com/forum/showth...9831#post29831
Cold and hot restart not delivering commanded fuel enrichment. Infact, it seems to be doing the opposite and leaning it out for a short period of time.
Phil
http://www.hptuners.com/forum/showth...9831#post29831
Cold and hot restart not delivering commanded fuel enrichment. Infact, it seems to be doing the opposite and leaning it out for a short period of time.
Phil
To me it seems there has to be some sort of timer, if the car is off for xx amount of time revert to table a for correction. Seems after the car sits for a while it is off a lot. Warm starts are even worse. Since it seems to be fine with a MAF on the car I would be willing to bet it has to do with the air temperature. Have you noticed any of this or how it changed on a start with an ambient of about 80*F?
For me, on a warm start, coolant temp is hot and intake temp is cold. So if it is going off the coolant temp more than intake air temp it would run leaner becuase the air would be colder then the computer thinks. I wondered if the bias factor had something to do with this but did not notice much change when I adjsuted it closer to IAT.
When the car is warm it gets better. I also noticed with increasing oil temp the idle AFR will slowly richen up. It may be 14.5:1 with cold oil and 14.0:1 with warm oil. I like to tune the car with the oil temp in the 170-190 range. Last time I went out with high rpms and got the oil over 200* my car was leaner when the temps were normal at about 180*.
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
Also, I figure on a cold start it takes a while for hte metal to heat up, the coolant temp warms up but the block is still fairly cool, so the intake charge is colder expected based on the bias factor leaning more towards ECT. Now I dont know how much it really effects it but that is the only table I am seeing that would pose any issue, maybe I will set it to 0 for my next log.
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
I agree on the timer part. I swear the fueling issue mirrors the cold/hot start enrichment routines without the added fuel.
Phil
The older PCM code doesn't use the manifold heating calculated air temperature. It uses pure IAT. The bias table shown in the editor isn't actually used by the PCM.
My theory is, when you tune your VE table with a warmed up engine you are actually tuning it leaner than you would normally because the PCM isn't accounting for the air charge heating (density change) between the IAT sensor and the cylinder.
It follows that when the engine/manifold is cold (ie. cold start) your tune will be lean because the air is denser (less heating) but the PCM doesn't know it. As the engine warms up, your tune falls back into line.
I'm going to look at making this better in the 1bar SD Enhancement, no timeframe as yet.
Chris...
I count sheep in hex...
Thanks Chris for all the help, like I said you can let me know if you need me to test anything (if it is able to actually be done). Until then I will make adjustments in the OLFA table.
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
Chris,
No dice on that. An example is vehicle fully warmed and set to 13.7afr commaned and deleiverd. Turn it off and restart it, it will run 16-17:1 for a period of time.
Phil
this is true, I would think the air in the manifold would be hot for sure on a restart, never really thought about that one.Originally Posted by NTIMID8
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
is this totally openloop? or are your fuel trims changing after the off/restart?
I count sheep in hex...
Completely open loop. No fuel trim changes, short or long.
Give me a list or email me a cfg file to do some logging for you if you wish.
It has me baffled and frustrated and entertained all in one.
It does show the correct commanded enrichment on cold or hot restart. It just doesnt deliever it and actually does the opposite and leans it out.
Phil
I took out all start up enrichment before for the hell of it to see what was going on and commanded 14.63:1 and the car was so lean it wouldnt even run
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
look at your cranking fuel...
Engine-> General-> General fuel->
caranking fuel....there is a leanout vs Rpm vs ect table and a set of tables for time frame...
set all these tables to 1.0
and see what a difference it makes...
theres a whole slew of tables..but those first 3 could possibly take care of it..I think...LOL..maybe??
Last edited by S2H; 02-06-2006 at 11:19 PM.
-Scott -
although probably not an issue, please make sure the IAT is staying consistent after the restart.
There is only a few things that could cause this, especially if the commanded AFR is correct. It can only be MAP, IAT or some of the injector code.
Chris...
I count sheep in hex...
IATs are fine. The map range seems normal for that rpm range on startup.
Chris, would you like something specific logged and sent?
Phil
my IAT and MAP stay constant
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
I dont have that table in mine
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
I am going to scan from a cold cold start right now, let the car sit for 20 min and do it again, then I will email you the scan again Chris. I will put AFR markers in every time I see it change
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
do you have a 2001/2002 liscense...
update your OS to one of those and you will see a whole bunch of new tables..
-Scott -
send me your bin/hpt file and a scanner log showing:
RPM
TPS
IAT
ECT
InjPW
Cylair
commanded afr
WBO2 AFR (if you have it)
ltft
stft
EVAP duty cycle
"closed loop fuel" status bit
"fuel trim learn" status bit
O2 voltages
if there is any case where the engine starts and doesn't go lean be sure to send it as well.
Chris...
I count sheep in hex...
I would but I dont have the license for either one of those
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
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