OUT WITH THE OLD VW. IN WITH THE SUBARU

[dsrace]

the craziest part is its didnt do it when you unhooked the cam sensor. but then after running it a while with cam sensor unplugged it started doing it again. so it ran better in limp mode but then it must have re learned or its a mechanical issue and its coming apart or your timing belt jumped a tooth. just my thoughts

[big dave]

so big dave.......when it acts like it hits the rev limiter, does it spit and pop a tiny bit like rev limiter mixed with small miss or tiny back fire?   also, in your ecm.......is there a setting for auto or manual trans? if so is the gear based map selection? if so could it be stuck in N map?

The ECU sets a rev, limit. It will flag that in the fault codes. it pop and cracks. there is no auto/manual trans. function in the Ecu

[dsrace]

if it pops and cracks a bit when it hits that rev limit , i bet your timing belt slipped a tooth or 2.

[dsrace]

thats what sucks about belts vs timing chains. turn that motor backwards by accident and you run the risk of jumping a tooth.

[fabr]

the craziest part is its didnt do it when you unhooked the cam sensor. but then after running it a while with cam sensor unplugged it started doing it again. so it ran better in limp mode but then it must have re learned or its a mechanical issue and its coming apart or your timing belt jumped a tooth. just my thoughts

This is why I don't suspect a slipped tooth. If it was a slipped tooth it wouldn't run better in limp mode even for a moment.

[fabr]

that's what sucks about belts vs timing chains. turn that motor backwards by accident and you run the risk of jumping a tooth.

I assume a subi belt is hydraulically tensioned? If so,don't you guys replace it with a manual tensioner for performance applications?

[DeepBusch69]

I assume a subi belt is hydraulically tensioned? If so,don't you guys replace it with a manual tensioner for performance applications?

I run the stock hydraulic tensioner, it is pretty stout, but I did add a part from outback that limits the space round the belt, so it makes it hard to jump a tooth. 

[Carlriddle]

[dsrace]

This is why I don't suspect a slipped tooth. If it was a slipped tooth it wouldn't run better in limp mode even for a moment.

i would tend to agree, however , big dave did replace the timing belt i believe before he fired the motor off for the first time. that link ecu requires he teach it the timing of the motor so he had to sinq it with the crank sensor on set up before he started it. if it skipped a tooth that could be as a possiblilty.

[dsrace]

[fabr]

i would tend to agree, however , big dave did replace the timing belt i believe before he fired the motor off for the first time. that link ecu requires he teach it the timing of the motor so he had to sinq it with the crank sensor on set up before he started it. if it skipped a tooth that could be as a possiblilty.

It would never run right if there was a skipped tooth. Never.

[fabr]

It does sound like the cam sensor is involved somehow.Whether it is the sensor itself or perhaps electrical noise in the harness causing the issue. Is the cam sensor wire ran anywhere close to a plug wire/coil/parallel with other wiring? I know noise is a big ,big issue with efi.

[dsrace]

well he did say this motor has never had the power he hoped for. so like that busa motor i had......it was off 1 tooth and made it run like a dog. eventually it started sort of back firing out the intake on decel. always started always ran just ran like i had an anchor hanging out the back.                             but good question  on cam wiring next to coil wires or coil. also brings up another question........is your ecu case grounded? i drilled a hole in my case and soldered a wire into it then ran that to batt ground. mine was built to be held in a metal bracket that was grounded to the car chassis. i cannot do the same in my trunck....instead i used velcro which helps reduce vibration too.

[big dave]

thanks for all the feed back on this problem. I have replaced both the cam and crank sensors. the sensing wires run  away from all coil and plug wires. the sensor wires do run in a common harness back to the ecm.  I tested all ground with ohm meter thy seem to be fine. I found at first, if I unplugged the cam sensor after staring the motor it would run to 6500 rpm. Sooooo. I had to go play!!!. ran it two days on the sand, with a switch on the cam sensor. switching the cam sensor off, after start up it would run  ok. The 3rd day  it would stay in the rev limit status. with the switch in ether position. I have not looked at it since  then. I needed a break. that or it was a can of gas and a flame thrower.    .

[fabr]

thanks for all the feed back on this problem. I have replaced both the cam and crank sensors. the sensing wires run  away from all coil and plug wires. the sensor wires do run in a common harness back to the ecm.  I tested all ground with ohm meter thy seem to be fine. I found at first, if I unplugged the cam sensor after staring the motor it would run to 6500 rpm. Sooooo. I had to go play!!!. ran it two days on the sand, with a switch on the cam sensor. switching the cam sensor off, after start up it would run  ok. The 3rd day  it would stay in the rev limit status. with the switch in ether position. I have not looked at it since  then. I needed a break. that or it was a can of gas and a flame thrower.    .

Are they ran parallel to each other or as twisted pairs? I know they need to be twisted pairs or bad stuff can happen. I don't know if any of this is related to your rpm limiting though.Do I recall you saying the ecm reads out a set 3800 rpm limit or that is all it will rev to?