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Discussion Starter · #1 ·
Ok today for no good reason my car started running like crap. I boosted out of a drieway and had gone about 2 miles at 45mph when the car stated to miss. Shortly after that I noticed it was running rich too because when it would sputter it would ignite the fuel in the exhaust. I did have a similar experience with this one day after washing the car but the CEL never came on and the problem went away by itself (wet igniter or map?).

So I limped it home and tryed to check for codes, but my ECU is crap and wont show codes. I tried resetting the ECU and it did nothing.

ATM it makes my eyes water at idle and wont hold any RPM without breaking up and almost stalling when I let off the throttle. Also I noticed about a 3deg temp increase and the vacuum at idle went from 20+ before to about 18 now...

So tomorrow when I start getting into it a little deeper what do you guys thing I should look at?

Spark
Map
Igniter
Fuel?

Hell I dunno, but this means Its time for a drink! :beer: :crying:
 

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JZA70 448 rwhp everyday
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mabyee 2 much fuel pressure do u have a AFPR? try a new o2 sensor for shur, make sure ur timing belt didnt slip a tooth as well.

~scott
 

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both of your symptoms sound like a map issue.

i would also try swapping a known good ignitor in there, and possibly an ecu as it is common for the injector drivers to head south.
 

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Discussion Starter · #4 ·
Thanks, as I said before my ECU is already crap...the Idle control doesnt work as is and Im sure its going south quick. But I just wish I did something dramatic so I would know what I did and possibly what I can do to fix it, but I think its just some gay electrical problem.
 

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i had a similar problem last year and it was my igniter starting to fail. it never failed completely, but would work sometimes and other times not work, on one cylinder.
 

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Now with 0JZ
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I would second the motion that it's a bad ECU. They do fail, and fail just like you have stated. Check your injector signals to see if they are stuck open.
 

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Poopra King
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I have a similar problem....kinda. At lower boost/RPMs my car runs a hard lean, then richens up way too much above 13psi
 

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Poopra King
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I was wondering how the HKS FCD affects the MAP signal and therefore the a/f ratios. I had it on 9, now it's on 8 and it seems to have more of a lean condition than when it was on 9. When it was on 9 it had a small lean condition down low and a really bad rich.
 

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Discussion Starter · #10 ·
OK, looks like its the MAP.

Found out that when I disconnected the MAP it made no difference in the way the car ran. So it looks like its not working at all.

Now a new question, if I use a 2j map will it still work correctly w/o tuning or 440's? Its my understanding that it will just lean it up a little.
 

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Poopra King
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I didn't know you could test the MAP like that. I'm gonna try the same thing. My wild A/F ratios are starting to scare me.
 

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Discussion Starter · #12 ·
Well disconnecting the map made no difference in the way the car ran, so I think im correct in assuming that the map is not functioning...
 

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Poopra King
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Is that the piece that's screwed into the intake manifold?
 

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pituala said:
Is that the piece that's screwed into the intake manifold?

I believe your problem have to do with the fuel pump. If your fuel pressure are at 35+psi and have not done the 12v mod then you will have low rpm miss/sputter running lean.
 

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Poopra King
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KrippleTwin said:
I believe your problem have to do with the fuel pump. If your fuel pressure are at 35+psi and have not done the 12v mod then you will have low rpm miss/sputter running lean.
I'm not sure what you're talking about....but please tell me more as. I can tell you I have a Walbro 255 pump, at idle I'm at 40psi fuel, and with the regulator vacuum hose unplugged I get 50psi. I thought I briefly saw something about this somewhere, but canb't remember exactly.
 

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If you drop your fuel pressure down to 32psi (now you're @ 40psi) your issue should be solve. If you dont want to drop your fuel pressure then you will need to by pass the fuel pump resistor(12volt mod). In low rpm the fuel pump only seeing/getting 9.5 volts to 10 volts. The walbro pump hates low voltage and high pressure. When you're done with the 12volt mod, you can set your fuel pressure as high as you want.


pituala said:
I'm not sure what you're talking about....but please tell me more as. I can tell you I have a Walbro 255 pump, at idle I'm at 40psi fuel, and with the regulator vacuum hose unplugged I get 50psi. I thought I briefly saw something about this somewhere, but canb't remember exactly.
 

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Poopra King
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Ok, so I can either get an adjustable fuel pressure regulator and adjust the pressure down to 32psi, or do the 12v mod, correct? I need to see if I can find the instructions on the 12v mod. I actually would like to get a nice regulator, but for the time being if I can do the 12v mod to keep it on the cheap for now (as I just spent $500 on a waterpump, pulley, oil filter bolt, and twin electric fans).
 

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Poopra King
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Oh yeah, thats right! When I was at the track I tried pumping up the boost once to 18psi and it blew my MAP hose off as well and the car started running like crap. I forgot all about that.
 
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