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"Ze Germans"
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730 Posts
Discussion Starter · #1 ·
Hi guys, I got basically two issues that might result from the same cause.
Car is a 2000 J-Spec RZ TT (VVTI engine with MAF), 100% stock.

I am having AFR issues for a few years already (every smog test is a pain).
Car is basically running a little too rich.
Additionally, since last year the car is having slight hiccups under load.
Barely noticiable, but they are there.
Beginning of this year the hiccups got worse. Tightened down all the air hose clamps, issue gone!
But now there is still from time to time hiccups again. Very sporadic.
So it seems as if this issue is related to air since MAF 2JZs are very sensitive to boost leaks.

Since having these issues I have already done the following:
  • new spark plugs
  • brand new TOYOTA coils
  • new coil connectors
  • new O2-Sensor
  • used MAF
  • checked fuel pressure
  • used catalytic converter

my hoses are looking not that nice anymore, they are 20 years old.
Did anyone else noticed worn boost hoses being a cause for issues on a 2JZ?
Any other ideas?
 

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1,578 Posts
Absolutely - old hoses can have splits in them that you can't see until they're under pressure. Also, it may simply be the ECU slowly failing. If you can, pull it out, open it up and check the capacitors for bulges and leaks. That's happening more and more now as these systems age out.
 

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247 Posts
Try changing ignitor and if it's the same then change the OEM ecu, borrow from a local owner if you can before spending.
 

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As mentioned above, check the ECU for leaky capacitors. It seems like there is about one post a month of a car running erratically and its seems like a good amount of those posts end up with a picture of a capacitor taking a dump on the ECU.
 

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"Ze Germans"
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730 Posts
Discussion Starter · #6 ·
Hi guys thanks for the heads up! Anyone ever had a VVTI ecu failing? I know These are Kinda rare but it is mainly NA ECUs failing I hear about
 

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From the land down under
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5,541 Posts
Have your cleaner the MA
Hi guys thanks for the heads up! Anyone ever had a VVTI ecu failing? I know These are Kinda rare but it is mainly NA ECUs failing I hear about
I havent seen one go bad personally, but a capacitor is a capacitor, and while your car is "newer" that most others, its still 22 years old, and depending on where the car lived, how often its been used etc, your ecu might be bad.

As a first port of call, I would pop the cover off and take a peek...as you might see something really obvious in there
 

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"Ze Germans"
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730 Posts
Discussion Starter · #8 ·
Nope I did not attempt to clean the MAF. My buddy killed his US-Spec NA MAF by simply cleaning it and generally cleaning a MAF is nothing that really is recommended.

Is the ECU Housing sealed by an adhesive or just simple screws?
 

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You can always hook up a multimeter to the output voltage on the MAF and see how steady the voltage is..... if the idle voltage is erratic, it could be a maf issue. If the voltage is too low, it could indicate a vacuum leak, etc... im sure if dig enough, you can find a voltage output vs flow to get an idea of what voltage should be like 0.5 volt at 800 RPMs....
 
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