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logger info -- ?? duty cycle and mmcd ??
http://4g61t.org/forum/viewtopic.php?f=6&t=15644		 Page 1 of 2
Author:  d1verDSM [ Thu Oct 27, 2005 10:45 pm ]
Post subject:  logger info -- ?? duty cycle and mmcd ??
ok so i started tuning a little today. up the boost on the 20g too around 15psi - 17psi mY afr was 10.6 (still way rich) across at WOT . but i was still getting knock , around 5-8 counts my injector duty on mmcd is up too 104 % .. WTF how is this possible i got 660cc's people on dsm quebec are telling that i wont max out my 660 with a 20g at even 20 psi ..

so either the guy on dsm canada fruit and banana me over , and i dont have 660cc'S . or there is something i aint getting right here.




oh and BTW car still pulls like a mofo , cant hook third at barely 17psi , have too tune in fourth.. im aiming for a 11.3 - 11.4 afr. but im scared about the duty of my injectors .. can i trust the mmcd reading on this ?
Author:  Crackerman [ Fri Oct 28, 2005 8:28 am ]
Post subject: 
IF they are 660's you definitely shouldn't max them out with a 20g.

borrow another logger and compare the 2. anything over 80% in street tune is a little too much, ideally you want to be a bit less than that.

what kind of fuel pump do you have? if you have a stock dsm pump, UPGRADE! i was running 94% duty cycle on my 14b at 18psi on stock injectors, when i put in the wablro 255 my duty cycle went back down into the 80's.
Author:  d1verDSM [ Fri Oct 28, 2005 4:20 pm ]
Post subject: 
i have a walbroo 255 , but im still on the stock fuel pressure regulator .. any of you guys know if its a must too up the fuel pressure when your running bigger injectors
Author:  Flying Eagle [ Fri Oct 28, 2005 6:00 pm ]
Post subject: 
Not the solution, but you will overrun your fuel pressure regulator soon enough with a 255 behind it.
Author:  ILLICON [ Mon Oct 31, 2005 12:28 pm ]
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don't know about that ^^ I run stock FPR, 660's, afc and 255 and I didn't max out my fuel system on a 20g nor my new turbo which is way bigger
Author:  OGP [ Mon Oct 31, 2005 12:40 pm ]
Post subject: 
If your running too rich you can create knock as well. Also are you sure its not mechanical knock? Does it varry when you chnage the A/F? While a good FPR can hold down a 255 fine, when most people say it won't its becuase someone straped there nice new 255 onto a worn out 100k plus fuel system, so an already tired fpr gave up. Just make sure you have correct fuel pressure this seems to be very overlooked. Stock FPR tend to give it up at the 100k mark-so may wish to upgrade or get a new one. Every cars a lil diffrnet as well, I know mine on the SMIC would knock at anything above 15 psi on piss gas.
Author:  MidwestDSM [ Tue Nov 01, 2005 3:53 am ]
Post subject: 
you need a new FPR, plain and simple. Whether its the problem or not, you've got too much money wrapped up in this not to do it right.

Also, I always assumed anything under like 8 or 9 counts was phantom knock, because hell, its a DSM, and alot of shit rattled around under the hood.

I'd still check that FPR and see what you can come up with. Even if you buy a new one and it doesnt fix it, you would still need it eventually so it would be worth the money.
Author:  d1verDSM [ Tue Nov 01, 2005 5:18 pm ]
Post subject: 
great responses guys , il check into a new FPR , and ill bring down my fuel , because right now in at 10.3- 10.6 AFR at WOT .. is that way too rich ?

Il be aiming for 11.4- 11.6 AFR . Safe ?? i also always run my car on 94 oct


I have another problem i cant seem too fix , its my low fuel trim. Its at 139 % ? So should i richen up my idle . ?
Author:  pma1123 [ Wed Nov 02, 2005 9:55 pm ]
Post subject: 
What are you using for fuel control?

Definetely start bringing up the fuel correction on the idle till your narrowband O2 starts cycling. Drive for a day or so and check to see where the low trim moves to. Readjust accordingly if needed.

Remember, as you turn down fuel pressure, you also decrease the headroom of your injectors where its really needed.

After doing my last headgasket from continued 11.5 region operation, I try to keep my tune in the ragged edge of 11.0. I'd personally rather make a few less HP and be safe, than push coolant and fill up the overflow tank after a hard run. :wink:
Author:  d1verDSM [ Wed Nov 02, 2005 11:24 pm ]
Post subject: 
funny thing is , my narrow band o2 does cycle at idle, and my wide band afr at idle is at a perfect 14.6 14.7 but yet i still get a bog for a fraction of a second when i depress the gas pesal fairly fast. Ive search many forums and i am pretty sure is what you call ,a lean tip in . Because my afr spikes too 18 - 22 about. But if i fix my low trim and manage too bring it back too 100 % maybe the bog yould go away.

So should i turn up the idle knob on the Maft ?



fuel fuel control im using a ,mafT 3.5 inch gm maf , + safc (blue screen version 1 ) with 660cc's on a walbro pump.
Author:  d1verDSM [ Fri Nov 04, 2005 4:29 pm ]
Post subject: 
okay .. my o2 seems too have stopped cylcing now ?? its stuck at .01 or soo at idle .. but when im driving around it does cycle. Anyone had this happen too them , is it time for a new o2 ?
Author:  The Ethereal [ Wed Nov 09, 2005 9:25 am ]
Post subject: 
Nope, you're just running too lean at idle.
Author:  ScottSpecV [ Wed Nov 09, 2005 9:50 am ]
Post subject: 
That and are you runnign stock spark plugs? You'll definately need to go a step colder. Otherwise you could definately be getting misfires under boost because of the plugs.

I had a similar idle problem, too. Made the driveability really suck. I fixed it by richening up the mixture at idle.
Author:  d1verDSM [ Fri Nov 11, 2005 10:56 am ]
Post subject: 
Ok i manage too get my o2 cycling at idle , my maft idle knob is on 2 , and my afc is up too 23 % my ltrim passed from 139 % too 89 % but its not stable , it keep going up and down , sometime up too 113 % then back too 89 % then 83 % blablabla you get the picture , my innovate reads a little rich 14.0- 13.2 depending on what the low trim decides too do. But here is the weird part, my low trim climbs too 114 % enven thow my innovate reads a 13.5 afr ?? so then my afr gets even richer like 12.5 and the car wont hold ilde when i let off gas fast.

How could i test my frp selenoid ? maybe thats whats pita.
Author:  SpinMasta11 [ Fri Nov 11, 2005 10:52 pm ]
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You can actually get rid of the fuel pressure selenoid. The only thing its for is high altitude starts where the atmospheric pressure is lower.
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