scalling issues with maf, idle hz is off in closed loop, forced open its perfect.
Jun 15, 2011, 09:25 PM
#1
scalling issues with maf, idle hz is off in closed loop, forced open its perfect.
Like the title says . I want to make the switch to SD 2.0, but I want my maf tune to be in check before I make the transition. I have been tuning in open loop for a while with ok results, drivability is ok, afr isnt ideal in every spot but close. I decided to scale my injectors pte 1000cc using figures that were posted in the supermerge. With a slight touch to the maf scaling table at idle I started to let the car run and my low trim was -.1 and my mid trim was +9%. I proceeded to make the change to the appropriate V and flashed. After that my idle Hz went to 60 and I cannot get it back down. I flashed my previous forced open loop tune, it idles at 37.5, then changed that Rom to accept closed loop and idle instant change to 50~60Hz and super lean. I'm stumped .. the Rom I used and got good trim the first time only needed a slight tweak. That same Rom unchanged yields an unacceptable idle Hz now and lean idle.100 percent guaranteed to have not changed any parameter in that Rom. Yes boost leak free... I'm just not getting how cl idles at a different Hz than ol. And I'm not sure how a single Rom went from works to doesn't. I've duplicated that Rom from scratch and still fails. Anyone have insightful thoughts or a test I can do to check things out ?
Jun 16, 2011, 06:45 AM
#3
Evolving Member
good question
I tried modifying the scaling first because I read nothing about the topic and just tried this on my own to try and make my AFRMAP match reality (afrs were like a rollercoaster and +-1.5afr off the map :/)
I then read a bit, switched to 2-byte airflow (allows MAF to read up to 2600Hz) and this time only changed MAFcompensation.
Same result if you ask me...my "fixed" VDR curves are almost on top of each other.
But my car is "weird" nothing works as expected so it may well be different on yours.
I tried modifying the scaling first because I read nothing about the topic and just tried this on my own to try and make my AFRMAP match reality (afrs were like a rollercoaster and +-1.5afr off the map :/)
I then read a bit, switched to 2-byte airflow (allows MAF to read up to 2600Hz) and this time only changed MAFcompensation.
Same result if you ask me...my "fixed" VDR curves are almost on top of each other.
But my car is "weird" nothing works as expected so it may well be different on yours.
Jun 16, 2011, 08:22 AM
#4
Well I am not sure how to go about the maf adjustment to make the afrs match the fuel map. Is that what you're talking about? Going speed density 2.0 so injector scaling and closed loop are my main concern so I can force ol at first to dial in SD. There is a bunch of ways to skin this cat I'm just not sure which cat to kill..
Jun 16, 2011, 04:53 PM
#6
this is frustrating. I am using the base scalings from the supermerge, and i ended up with 7%L and 9% mid. So I scale back to 713, and it gets worse.. Now It peaks @ 10% mid, and stft is completely maxed out all the time. Do I have to adjust something in the maf scaling? Both numbers are positive, so I decreased the injector scaling number. its a simple instruction for me, but not for my car! Also if Im sitting at idle my Hz bounces from 37.5 > 43 some times, and at other times it sticks around 50 60 hz. But 75% of the time it idles at 37.5. What is the cause for this such erratic behavior? I really need to learn this, but it has zero consistency to its function!
Jun 16, 2011, 05:34 PM
#7
i would leave the maf scaling stock for now and focus on scaling the injectors. thats just me though.
i also have pte 1000cc injectors with S2 cams. i tried the scalings that were on that thread and they were way off for my car. some didnt even let the car start.
i ended up with a scaling of 886
with latencies of:
3.192
2.088
1.44
1.08
0.84
0.672
0.552
this has given me trims (low/mid) of +/-1.8%
now im just battling warm start issues but i recently added the extra fuel tables that MrFred posted the other day. hopefully this works. you should try these trims and see how it works out for you
i also have pte 1000cc injectors with S2 cams. i tried the scalings that were on that thread and they were way off for my car. some didnt even let the car start.
i ended up with a scaling of 886
with latencies of:
3.192
2.088
1.44
1.08
0.84
0.672
0.552
this has given me trims (low/mid) of +/-1.8%
now im just battling warm start issues but i recently added the extra fuel tables that MrFred posted the other day. hopefully this works. you should try these trims and see how it works out for you
Last edited by vmrevo9; Jun 16, 2011 at 05:38 PM.
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Jun 17, 2011, 07:06 AM
#12
I've used your numbers before but I was told just cause the trim is good doesn't mean its the right scaling ..lol
I honestly dont know why that could be. Everyone that tells me what numbers to use is adament about the scaling and latency being whats in the supermerge, but in your case and my case, they are extremely incorrect. latency figures nearly double, and injector scaling leans way out. Sounds like these injectors may be more sluggish in some cars vs others.
I honestly dont know why that could be. Everyone that tells me what numbers to use is adament about the scaling and latency being whats in the supermerge, but in your case and my case, they are extremely incorrect. latency figures nearly double, and injector scaling leans way out. Sounds like these injectors may be more sluggish in some cars vs others.
Last edited by 211Ratsbud; Jun 17, 2011 at 01:10 PM.
Jun 17, 2011, 01:21 PM
#13
Ok, I have been in contact with PTE and got the latency values they recomend for starting, and they are very different from the supermerge. I asked if I could post the values he gave me, and I was denied that permission. So if anyone wants to start from values that are suggested by the manufacturer, email/call Precision Turbo & Engine, ask for Scott. I have yet to try them, however at the voltages of a running car they are very close to the gentleman in this thread who posted his working values.
Jun 17, 2011, 03:46 PM
#14
I've used your numbers before but I was told just cause the trim is good doesn't mean its the right scaling ..lol
I honestly dont know why that could be. Everyone that tells me what numbers to use is adament about the scaling and latency being whats in the supermerge, but in your case and my case, they are extremely incorrect. latency figures nearly double, and injector scaling leans way out. Sounds like these injectors may be more sluggish in some cars vs others.
I honestly dont know why that could be. Everyone that tells me what numbers to use is adament about the scaling and latency being whats in the supermerge, but in your case and my case, they are extremely incorrect. latency figures nearly double, and injector scaling leans way out. Sounds like these injectors may be more sluggish in some cars vs others.
i have always been under the assumption that if your fuel trims are good than your pretty close if not dead on. obviously 0% would be ideal but in a real world that is not going to happen. its interesting that the same set of injectors can scale differently on diferent evos. i guess mods will have alot to do with it.
its taking me quite some time to get the idle and trims where they are on my car. i have my idle set to 1060 and it fluctuates +/- 30 rpms, AFR's range from 14.4-15.5. now im slowly taking care of the warm start issues.
Jun 18, 2011, 08:26 AM
#15
The only mod we have in common is the PTE 1000cc injectors. Im working on switching to 3d SD right now. Infact I am running it currently. While those trims worked good on maf, they are both - to a greater degree running SD, but I think that has to do with SD and not the scaling. Im not sure where to adjust that yet.
Last edited by 211Ratsbud; Jun 18, 2011 at 08:29 AM.