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JDM EJ205 No boost issue.

3K views 8 replies 2 participants last post by  SupraJunky101 
#1 ·
istory:

03 Bugeye 188K miles. Intake/Exhaust basic tune. Runs/drives fine. Head gaskets finally let go. Last drove it 9/10/16, no codes, no issues, other than leaking HG. Pulled the motor and bought a swap.

Replaced motor with JDM "low mileage" EJ205. Super clean motor. V8 EJ207 big port heads. Zero sports turbo (Essentially a VF30). Dropped JDM motor in, untouched. Using JDM V7 Ecu. Fired right up. Running open downpipe just while I get the car dialed in. Idle is ****ty so I narrow it down to IACV. Looks like it got banged up during shipping.

Replaced IACV, idle solved. Idles great. Fresh fluids. 3/4 tank of 100 Octane fuel to appease the JDM V7 Ecu. Went for a drive, no boost. Not 1psi. Car idles great, sounds great, revs freely at idle and in neutral. Won't build any boost. Per boost gauge, car sits at right around 20 mHg in vacuum, under acceleration it reaches zero and then stays there.

I have not done a proper boost leak test, however I have replaced almost all the hoses and at this point checked them 4, 5, 6 times.

Two codes : P0365 P0390. However they are as a result of me not wiring up AVCS yet. No other codes.

What I've checked so far:

All vac lines I removed and installed during swap.
BPV gasket replaced.
TMIC replaced with STI TMIC, coupler replaced, new clamps, checked Y pipe and all other clamps.
Checked BPV to ensure it's not stuck open, functions as it should.
Checked all wiring to ensure no broken connections or loose wires to put the car in limp mode (although no codes).
Boost pill still in line and all hoses connected to their respective sources.
Intake hose tight and MAF appears clean.
Replaced turbo inlet hose which had a rip.
Wastegate moves back and forth with pliers, C-clip still attached.
Ran hose from WG to compressor housing, bypassing BCS.
Tried a second, different ECU from V7 STI.
Removed turbo today, no shaft play, spins freely, no cracks in WG housing.
Looked down in up-pipe, EGT probe still in place and cat in the up-pipe is intact and undamaged.

After checking and swapping all the parts above, no change. No boost.

Initially I thought a leak, but I am not getting low psi, I am getting none at all.

Thoughts ? What am I missing here, did my motor come with a bad turbo ? :face:
 
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#2 ·
Could be a bad turbo, bad wastegate (or wastegate acctuator), massive boost leak (or exhaust leak), an issue with sensors.. probably a few other things. First thing I would do is check learning view, specifically fuel trims, and see if anything looks screwy there.


For what it's worth, 98 RON (octane) in Japan is equivalent to 94 (R+M)/2 that we use in the US. With the conservative factory tune, as well as the ethanol content in most US fuel you should be perfectly fine running 93 octane. There's no advantage to running 100 octane.. other than making your wallet lighter.
 
#3 ·
I tried the wastage actuator with pliers and I can manipulate it open. Snaps back in place when I let go. C clip is still on the arm and attached.

As far as exhaust leaks, only spot I haven't checked that it could be is the factory up pipe where it connects to the crossover. I'll pull off all the heat shields and check but I can't hear anything. I would expect it to be audible if it was that bad.

I don't know where elsewhere that significant of a boost leak would be as I've checked all the hoses, TMIC, BPV, etc.

Aside from a scan tool I don't have any diagnostic tools. I'm going to look into getting a tactrix to monitor.

I put the fuel in there as a safety measure to prevent knock just to get everything dialed in.

I'm going to try and source a cheap td04 just to try it...
 
#6 ·
Aftermarket modified turbo? That could have something to do with your issue.. I haven't seen much about Zero Sports other than various cheap knock off exterior pieces here and there over the years.

You could try blowing compressed air into the turbine inlet and see if it spins up freely and relatively noise free.
 
#7 ·
It's an IHI turbo with a zero sports plate. I read up on them when I bought the motorset. From what I read it's basically a VF30. I'll try compressed air, as it spins free by hand. No noises that I can hear though.

I have read some threads about a guy with a VF34 that was bad internally from oil starvation. He had almost exact symptoms to me. However I can't find anyway to check.
 
#8 ·
Update for anyone concerned.

Bought a used JDM sad small td04, removed VF Zerosports and slapped it in on the motor. Primed it and went for a drive.

I have boost. My gauge ( which is cheap and ****ty)reads 5psi, I'm betting it's 7 and I'm at waste gate pressure. Next step is replace boost control solenoid to rectify this and then fix any small leaks I may have.

What an absolutely nightmare this swap has been ??.
 
#9 ·
Another update.

Bought a BCS from the junkyard for ten bucks. Put new vac lines in it and went for a drive. Car boosts, I hit around 10psi according to my gauge but as I established yesterday the "NITROUS" brand gauge it came with is not overly accurate. (about 2psi off) so if I'm hitting 12psi that sounds about right.

I finally drove enough and made enough boost to trigger two more AVCS codes P0106 and P0108.

Spool is definitely sluggish and with these big port V8 heads it's not climbing RPM very fast. I'm accrediting this to the AVCS not being wired so it's not making the proper adjustments while going through powerband.

Or atleast that seems right in my head.

Going to bite the bullet and buy the kit to wire AVCS up, buy another VF turbo and then get it tuned :+1:?
 
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