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92 legacy will not rev over 4500 rpm


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Help needed. Engine is a 2ltr but been transplanted into a vw, it runs sweet for first minuite but after that it will not go over 4500 rpm, its like it is hitting a rev limmiter. I have changed air flow meter and o2 sencer but with no luck. I have seen other threads on here with same problem, is this a common fault? Any help appreciated.

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my first guess would be a clogged cat. Hit the cat (when cold) with your hand, do they rattle. Is there anything in the air intake that shouldnt be there

 

nipper

no cats on it, the exhaust is a one off custom because its in a vw camper van.

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What have you done for engine management? Are you using the stock ECU? You mentioned it being a 2 liter. Is this a JDM engine? The US models only came in 2.2 liter.

 

Please provide more info on the wiring and control setup, as that is likely the issue.

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What have you done for engine management? Are you using the stock ECU? You mentioned it being a 2 liter. Is this a JDM engine? The US models only came in 2.2 liter.

 

Please provide more info on the wiring and control setup, as that is likely the issue.

Over in uk subaru also offered the 2 ltr engine as well as the 2.2 . it has the stock ecu and the loom has been modified by a proffessional (just the wires to make engine run.... air con,power stering has all been cut out). It was out of an automatic but i dont think that would make a differance. Strange thing is it will run great for first couple of minuites then once it gets hot it will not go past 4500 rpm . could it be water temp senser?

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Sounds like the ECU is not reading speed, so it defaults to a lesser mode which allows the engine to run, but only up to 4500rpm. I have a friend who broke the speedo cable in his Impreza, the engine wouldn't go over 4500rpm until he replaced the cable, then everything was back to normal.

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Sounds like the ECU is not reading speed, so it defaults to a lesser mode which allows the engine to run, but only up to 4500rpm. I have a friend who broke the speedo cable in his Impreza, the engine wouldn't go over 4500rpm until he replaced the cable, then everything was back to normal.

the loom has been chopped up , no speed sensors on this , the only things connected to the ecu are air flow meter,o2 senser,all the sensors attatched to the engine itself and thats it.

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the loom has been chopped up , no speed sensors on this , the only things connected to the ecu are air flow meter,o2 senser,all the sensors attatched to the engine itself and thats it.
Yes, exactly there is no speed sensor, the ECU is not reading the sensor, so it is defaulting to the setting where the engine doesn't rev over 4500rpm.
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Yes, exactly there is no speed sensor, the ECU is not reading the sensor, so it is defaulting to the setting where the engine doesn't rev over 4500rpm.

that sounds like the problem!! I will have to think of a way to confuse the ecu so it looks like there is a speed sensor.

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that sounds like the problem!! I will have to think of a way to confuse the ecu so it looks like there is a speed sensor.

 

the guys on the yahoo list have a cheater box to solve that problem.

 

nipper

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