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.

ANy restrictions in the exhaust?

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

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.

well there is a clue. not sure what clue it is, but here is a clue.

 

nipper

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.

My guess is no oxegen sensors? This could make it run in limp mode could it not?

my guess is no cat. no cat no 02 sensors, or the o2 sensors are getting such an oddball reading its in limp mode.

 

nipper

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?

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.

ive seen this problem before on a yahoo list for subaru to vw conversions.

 

http://autos.groups.yahoo.com/group/subaruvanagon

 

check out there

 

nipper

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.

Speed sensor would be another thing that might make it do that. Good thought.

Unless you compensate for all that stuff the ECU is going to be looking for it.

Somebody must have done this before.

By the way I think Gnuman is working for a firm that puts Subie engines in VWs. You might pm him for info.

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.

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.

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