problems with miata
07-22-2007, 05:31 PM
#1
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problems with miata
so i took my miata to get it tuned it pushed good power but the safc is maxed out to 50% and its runing lean in boost do you guys think i could be a bad safc? or do you think my ecu is reading boost? in boost its runing 13:1 ratio and i am runing 8 psi in boost and the damn thing still runs lean and i have the lite purple 265 injectors! the guy that tuned it is just is stumped as me so any help would be great!!!!!
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07-22-2007, 08:19 PM
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You're really not giving us much, if anything, to work with.
What turbo? What was your dyno result? Where's the plot? You don't even tell us what year or motor.
Also slow down when you're typing and proof read. If I have to decipher quasi-english to english, I ain't gonna help ya nun.
What turbo? What was your dyno result? Where's the plot? You don't even tell us what year or motor.
Also slow down when you're typing and proof read. If I have to decipher quasi-english to english, I ain't gonna help ya nun.
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07-22-2007, 09:16 PM
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I would get a BEGi FMU, and probably throw away the SAFC and definately throw away ebay crap.
Why would you put cheap *** ebay chineese crap in charge of delivering fuel?
Why would you put cheap *** ebay chineese crap in charge of delivering fuel?
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07-22-2007, 09:38 PM
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Hell no. No way should you spend $400 between 2 fuel piggies.
Just get a BEGi FMU and be done.
If you want to spend $400 get a vortec and pick up a used emanage blue.
Or a new AEM piggy.
Or build a MegaSquirt.
Or spend a little more and get an MSPNP
Just get a BEGi FMU and be done.
If you want to spend $400 get a vortec and pick up a used emanage blue.
Or a new AEM piggy.
Or build a MegaSquirt.
Or spend a little more and get an MSPNP
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07-22-2007, 09:45 PM
#16
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so what tunes the car then? just the begi? and my injectors are ok? should i make and dual feed rail? could i get a e-manged instead?
Last edited by 90miata; 07-22-2007 at 10:10 PM.
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07-22-2007, 11:46 PM
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on your year miata.....
under 4-5k rpm (not sure what the cutoff point is) the stock ecu operates in a mode where it reads from the oxygen sensor and automatically adjusts inector pulse to keep the engine running stoich (14.7). Above 4-5k rpm (again i forget what the cut off is), the oxygen sensor and ecu stop working together, and the ecu feeds fuel according to a preset fuel map.
Therefore a real rising rate fuel pressure regulator like the begi or vortech, will only give you noticeable results after the motor hits the rpm at which the ecu goes into the preset map mode because at that time, the injector pulse width does not change according to what the o2 sensor and ecu determine should yield stoich....so the rrfpr simply clamps off the return line to your fuel tank, the pressure in your fuel rail increases, injector pulse stays a preset lenght, so the overall amount of fuel going into your motor increases.
to answere your main question...yes, without a piggy back of different ecu, the begi or vortech is what tunes your car (but only after the engine hits a certain rpm). to tune the air/fuel ratio below that magic rpm, you need an oxygen sensor clamp which allows the stock ecu to ignore the output coming from the o2 sensor and you to up the fuel pressure under the magic rpm with your begi or vortech.
if it doesn't make much sense....read up on your miata fuel system and it's return system, braineacks' faq, and corky's book maximum boost, and talk to olderguy about his oxygen sensor clamp.
you're on the right track, just need some details hammered out.
p.s. most of those ebay fpr's only up fuel pressure on a 1:1 ratio (1 pound of boost coming out the turbo only increases pressure at the rail by 1 pound)
the begie and vortechs rise fuel at a 6:1 - 12:1 ratio. that's what you're gonna need to get yourself running not lean.
Anthony
under 4-5k rpm (not sure what the cutoff point is) the stock ecu operates in a mode where it reads from the oxygen sensor and automatically adjusts inector pulse to keep the engine running stoich (14.7). Above 4-5k rpm (again i forget what the cut off is), the oxygen sensor and ecu stop working together, and the ecu feeds fuel according to a preset fuel map.
Therefore a real rising rate fuel pressure regulator like the begi or vortech, will only give you noticeable results after the motor hits the rpm at which the ecu goes into the preset map mode because at that time, the injector pulse width does not change according to what the o2 sensor and ecu determine should yield stoich....so the rrfpr simply clamps off the return line to your fuel tank, the pressure in your fuel rail increases, injector pulse stays a preset lenght, so the overall amount of fuel going into your motor increases.
to answere your main question...yes, without a piggy back of different ecu, the begi or vortech is what tunes your car (but only after the engine hits a certain rpm). to tune the air/fuel ratio below that magic rpm, you need an oxygen sensor clamp which allows the stock ecu to ignore the output coming from the o2 sensor and you to up the fuel pressure under the magic rpm with your begi or vortech.
if it doesn't make much sense....read up on your miata fuel system and it's return system, braineacks' faq, and corky's book maximum boost, and talk to olderguy about his oxygen sensor clamp.
you're on the right track, just need some details hammered out.
p.s. most of those ebay fpr's only up fuel pressure on a 1:1 ratio (1 pound of boost coming out the turbo only increases pressure at the rail by 1 pound)
the begie and vortechs rise fuel at a 6:1 - 12:1 ratio. that's what you're gonna need to get yourself running not lean.
Anthony
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07-22-2007, 11:52 PM
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The rest is so wrong I'm not even going to start with it, and should be ignored if not deleated.
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07-23-2007, 09:30 AM
#20
if you get a static ratio FMU, there's really not much to "tune".
If you keep the SAFC2, you'll have some level of tuneability by modifying the AFM output voltage that the ECU sees. Now, the FMU works off of pressure while the SAFC2 is reading off of mass so it's not an ideal solution but it'll probably work good enough.
I imagine you could hook up a MAP sensor to the S-AFC and tune by pressure but thats another bag of worms
If you keep the SAFC2, you'll have some level of tuneability by modifying the AFM output voltage that the ECU sees. Now, the FMU works off of pressure while the SAFC2 is reading off of mass so it's not an ideal solution but it'll probably work good enough.
I imagine you could hook up a MAP sensor to the S-AFC and tune by pressure but thats another bag of worms
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