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Odasi
91 v6 mr2
Joined
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35 Posts
Discussion Starter · #1 ·
I have a turbo 1mzfe controlled with an AEM FIC. I just got it done, so its not completly tuned yet. The problem is when ever I rev it up to about 5400 and about 10psi sounds like it is hitting a rev limiter and cant go past. Not under boost it will rev up to 6300 just fine. I had the timing cut back -1 degree per pound of boost when it did it first so i tried -.6 and -.5 and it still did it. Should i cut timing more or is that not the problem. Also I have an AEM Wideband that was giving me 13s and some 16s in the data logging in that area. I added more fuel in the area but still no change. I have 460cc RX-7 Injectors Pt. #195500-2010. The data logging showed about 60% duty cycle when it starts messing they jump between 60% and 120% in the log. Don't know what the problem is. I would appericate some help.
 

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Turbo Snail
Cam A Roo
Joined
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5,299 Posts
check your plugs , and try to cut the air hose that goes to the manifold pressure sensor and plug it up at both ends so that air can't get in or out. Your car is probably cutting out because the fuel cut mechanism works by using a pressure sensor that senses the amount of pressure in the intake manifold. This sensor works by producing an electrical signal that varies proportionally with the amount of pressure in the manifold. Try that and see what happens. You will loose your Boost gauge if you do this, but if it rev's up fine, then I would get tuned asap


Sounds to me like the sensor is messing with your fuel
 

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Turbo Snail
Cam A Roo
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5,299 Posts
yeah that could cause some problems. You could try to find a Supra TT MAF, that might solve your problem somewhat, but like i said i would look into getting a good tune before long.

I'm not quite sure if your ECU would even be able to use the Supra MAF either. i think if you use that MAF you may have to upgrade your injectors and possibly piggyback the whole system?

Im not really familiar with the 1mzfe and what its capable of though so those 1mzfe guys should clue in ....



Now :) lol
 

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Odasi
91 v6 mr2
Joined
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35 Posts
Discussion Starter · #8 ·
It's tuned ok. The A/F ration is fine at high RPM and about 10psi. It revs up all the way fine under about 5 psi too. Could the MAF cause something like that. In the data logging the injectors are jumping around from 60 to 120 percent when it messes up. before that there is a smooth increase up to around 60. Does this mean the ecu is throwing in a bunch of fuel? Or is this a secondary effect.
 

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Turbo Snail
Cam A Roo
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5,299 Posts
yeah a Mass Air Flow that is maxxed out could cause your Air Fuel Ratios to go all whacky definately. That would cause your ECU to not know do and would try to compensate with 60 to 120%. You could always try cleaning out the MAF to with some electrical safe cleaner. More than likely your MAF is causing your problems, but I am not 100% sure if changing it to one that has a higher tollerance would solve your problems or not?

If you have a supra MAF sitting around i guess it wouldnt hurt to hook it up and see what happens :)
 

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Registered
1999 Camry
Joined
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655 Posts
hey are you the one with the red mr2 and the big fother mucking dual exhaust ?

i honestly thought yuu had a supercharger cause it whines loud. but then i hear a bov when yuu shift so im like wtf ? lol

my friend and i are gonna go tune his sti up in chicago saturday cause he just replaced his turbo and full exhaust. im gonna go with him and see if i can learn anything about tuning because im saving up for the trd supercharger so im gonna learn as much as i can about tuning before i actually get the supercharger on.

anyways, i have a 1mz manual too (camry lol) so maybe we can meet up sometime ? i was gonna ask yuu if yuu had a 1mz with the trd supercharger or a 3sgte but then the light turned green and yuu shot off lol
 

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Odasi
91 v6 mr2
Joined
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35 Posts
Discussion Starter · #13 · (Edited)
I clamped the voltage of the MAF at 4 volts and it solved the problem. I did some data logging of reving up the engine with no boost and the MAF only got to 4 volts at around 6200rpm under boost itll hit 4 volts by 3500rpm. Maybe the ecu was freaking out when it saw too much air flow for a certain RPM??? In the data logging it didnt seem like a cut in fuel an the A/F ratio was ok, the injectors were doubling their duty cycle for a few hundredths of a second then going back to normal then doubling again. Weird.
 

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Odasi
91 v6 mr2
Joined
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35 Posts
Discussion Starter · #14 · (Edited)
It started cutting out again around 3500-3800rpm under 10psi but it will rev past that if not under boost. Im wondering if that air flow is of the chart for the ecu too. When i rev up the engine under no boost the MAF reads about 3.2 volts but at 10psi it is reading 4.7. I have the voltage clamped at 3.95 volts so that is what the ecu is seeing. Right where it starting cutting out is where the voltage starts sky rocketing. Im wondering if there is a voltage that is off the chart for that rpm and the ecu goes to fail safe and dumps a lot of fuel.
 

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Read lots, post little
2001 SXV20R Touring
Joined
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71 Posts
From what I have read the camry AF sensor is pretty shitty and seeing as your running a completely set of parameters thru it (boost) maybe you want to invest in a better sensor. Im looking at much the same thing, choking the MAF return signal can't be good for a proper tune either. Would love to get in touch in a few months when i start putting my build together. Also you are using RX7 injectors instead of supra injectors like most turbo 1MZ projects.
 

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Turbo Snail
Cam A Roo
Joined
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5,299 Posts
It started cutting out again around 3500-3800rpm under 10psi but it will rev past that if not under boost. Im wondering if that air flow is of the chart for the ecu too. When i rev up the engine under no boost the MAF reads about 3.2 volts but at 10psi it is reading 4.7. I have the voltage clamped at 3.95 volts so that is what the ecu is seeing. Right where it starting cutting out is where the voltage starts sky rocketing. Im wondering if there is a voltage that is off the chart for that rpm and the ecu goes to fail safe and dumps a lot of fuel.

Sounds like thats your problem. :thumbsup: It would cause your injectors to do funny stuff too because your ecu is trying to compensate
 
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