Help! Engine Rebuild Now Have A Canbus Comm. Issue

I recently removed, rebuilt, and re-installed a ej25 in a 08 legacy gt spec b. Ran great gave back to the guy (16 yr kid) and he proceeded to "hoon" for lack of a better word including doing what he thought was 2-step all before the piston rings were seated. Also he turned the boost up to 20 some psi. Not sure going off a guess he has an aftermarket atmospheric blow off valve on it and it was maxed out after we turned it down while we had it out.

 

Long story short, we rebuilt the motor again and this time when we put it in, it is slow to fire up (like a fuel issues), it runs with a miss (like a bad coil pack) but there are zero codes in the computer under engine. but it seems to me like its not completely recognizing all the systems in the car.

I've checked the grounds that i know of. (one on each cylinder head and the one up by the starter, and all fuses are good.)

 

Also woth noting it is a BRAND new battery in the car.

Any ideas?

Thanks in advance!

Make sure the white coil plugs are on the front coil packs. Some have swapped them, I believe the black connectors are the rear coils.

Thank you max,

Update: The coil packs are all plugged in correctly, determined that the passenger side was not firing at all. Pinned out the harness all good. gonna try 2 New coils

I recently removed, rebuilt, and re-installed a ej25 in a 08 legacy gt spec b. Ran great gave back to the guy (16 yr kid) and he proceeded to "hoon" for lack of a better word

Also woth noting it is a BRAND new battery in the car.

Any ideas?

Thanks in advance!

 

Bahaahah a 16 year old kid with a spec B . My shop told me a story like this and they now rev limit the cars and disabled things so this will not happen again. They told me with my age they would not do that cause I am far from 16 haha:). I drive like an old man my wife says.

Two questions - what makes you think CANbus issue, and what went into rebuild?

awfulwaffle.

I suspected a communication issue because our scanner wasn't recognizing all the on-board systems as well as the car not throwing a cel when literally only half the motor was running. I got the car running on all 4 now by replacing the coil packs (learned the hard way the are ran in series). Now the car runs like an absolute top at idle and in 1st gear, but as soon as you grab second gear it starts shutting down like you are running out of fuel.

Its Weird because you can lay into it in first gear but when you grab second it will throw you through the windshield.

 

I am completely lost on this one guys. Pulling the front cover to check the timing for the 3rd time now.

Also it is a stock rebuild, the first time be put new pistons, bearings, oil pump, water pump, timing belt tensioner etc, in it this time we just did new piston rings and head gaskets.

awfulwaffle.

I suspected a communication issue because our scanner wasn't recognizing all the on-board systems as well as the car not throwing a cel when literally only half the motor was running. I got the car running on all 4 now by replacing the coil packs (learned the hard way the are ran in series). Now the car runs like an absolute top at idle and in 1st gear, but as soon as you grab second gear it starts shutting down like you are running out of fuel.

Its Weird because you can lay into it in first gear but when you grab second it will throw you through the windshield.

 

I am completely lost on this one guys. Pulling the front cover to check the timing for the 3rd time now.

Also it is a stock rebuild, the first time be put new pistons, bearings, oil pump, water pump, timing belt tensioner etc, in it this time we just did new piston rings and head gaskets.

 

Why did you not just do a new shortblock, refresh heads and throw it back together? I am guessing it would be cheaper cause the SB was in good shape maybe. Did you get rid of the Bro off valve? I love the sound but these car hate them.

NORULZleggy

Kept the BOV but turned it back down and 8115'd it so he couldn't turn it back up.

Just threw piston rings and gaskets at it because all he did was not give the rings time to seat so it was pressurizing the oil block and blowing cam seals crank seals valve cover gaskets etc.

He brought it back in complaining of a "oil leak" ended up being an oil waterfall.

Found all the proof he was abusing it on his instagram (now private cause i called him out on it when he wanted it done under warranty).

I guessing a Tuner may have some thought's. The car runs great in first gear but falls on its face in second...

 

Is guess that's why your leaning towards a communication error.

But here's my problem, How does the car know its in second gear?

Its a M/T

Im guessing the engine load? But then again when you stand on it in 1st it puts the same load?

Maybe it sees the output speed against the rpms?

Im gonna try and put his cobb tuner on it and put it back to stock settings.

Maybe when it sat dead/disconnected it reset or lost some memory, but one one think it would go back to stock memory.

Just throwing this out there... did you check to make sure the green test connectors under the glove box are disconnected?

Sounds like a nightmare. Does he have a tuning interface like a Cobb Accessport? The answer is in the data, you can use the AccessPort to log.

Awful waffle

I got the kid to bring me his tuner, re flashed with the 91 stage 1 tune, same issue (i figured it reset something when the battery died) i am going to try and put it back to stock but i do not think that will help with the atmospheric bov.

I am getting a cel now. code p0036 (i cant remember for sure) for crankshaft sensor performance. i ohmed it first checked good, replaced it anyway for the hell of it (24.99$) and i even checked the timing for peace of mind all checks out.

Dave

No i haven't but i will right now

I think im on to something, tuner is showing car is always in vacuum. -11.psi im wondering if i have to boost contol valve hooked up backwards. i had the line coming from port f going into the rear and the one in the front (of the control valve) going back to the turbo.

http://i.imgur.com/62j7Qyc.png

There should be a vacuum picture in a sticky here...found it, hopefully that will help. There is a picture in the service manual too,

http://people.csail.mit.edu/ilh/vacation/

 

https://legacygt.com/forums/showthread.php/2005-2006-lgt-colored-vacuum-routing-diagram-143225.html

Thank you max, i'm about to lose it on this one. i've got all the issues narrowed down to one. P0336 crank position sensor error/performance, i've replaced it, shimmed it out, clearenced it to get it in closer it all makes it run worse. I've ohmed it, continuity tested it back to the main engine harness connection all checks out. Any ideas?

You sure timing's on?

You’re using the line on the crank sprocket not the arrow for timing alignment correct? Also check that no teeth are missing on the ring on the back of the sprocket. I believe someone here once had one missing a couple of teeth. Edited February 20, 2020 by DaveWaters

Haha GOT IT BOYS! I pulled it back down and pulled the crank sprocket off to inspect it further. As i was pulling it of i broke a tooth (being impatient and trying top pry it with a screwdriver) i went ahead and ordered another new belt for the hell of it (the belt that was on it was from the original rebuild 6-8m ago). Put it all back together and it runs like a top.

 

Maybe the belt stretched from abuse or maybe the crank sprocket was the issue. Although it looked perfectly good other than the one broken tooth.

 

I'm leaning towards the belt being the cause though, it was a good gates belt like i said it was less than a year old but im just glad I got it done.

 

And every time I checked the timing it checked out good so maybe the belt was stretching under load?

Great to hear.

 

For future reference, we don't recommend the Gates timing belt kit for these cars, anymore.

 

Aisin belt to the go to kit.

 

https://www.partsgeek.com/gbproducts/HC/18220-05437807.html?utm_source=google&utm_medium=ff&utm_content=HC&utm_campaign=PartsGeek+Google+Base&utm_term=2005-2009+Subaru+Legacy+Timing+Belt+Kit+Aisin+TKF-004+05-09+Subaru+Timing+Belt+Kit+06&fp=pp&gbm=a&utm_source=google&utm_medium=ff&utm_campaign=PartsGeek+Google+Basecid=6774379819&aid=79287199093&keyword=313464391599%3A%3Apla-313464391599&kid=313464391599&gclid=EAIaIQobChMI7t294s_i5wIVkJOzCh31UAaIEAQYBCABEgL44PD_BwE

What a nightmare.

 

Are we sure there are no other mods minus the BOV?

 

I wouldn't be surprised if this guy was running an aftermarket intake or Downpipe with the incorrect tune.