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Old 05-05-2012, 06:51 PM   #1
tenchu
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Default EJ20G barely running post-swap

I'm not sure how injector signal works, I was told it was a ground signal from ecu, but I have 12v coming into ecu (figured this out by unplugging connector from ecu and checking voltage at pins.

As far as I can tell, i have 4cyl of spark and 4cyl of fuel. Car will BARELY idle, but ANY additional throttle, the car dies. I've sprayed everywhere looking for vacuum leaks and cannot seem to find anything.

If I unplug the giant vacuum hose that goes to the brake booster, the car backfires, but idle gets a bit less lumpy.

TPS seems to have proper voltage at ECU

Brand new spark plugs (today)

Any ideas?
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Last edited by tenchu; 05-06-2012 at 10:47 AM.
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Old 05-05-2012, 07:12 PM   #2
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Here's a video of start, idle, pulling hose, reconnecting hose, then applying throttle

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Old 05-05-2012, 09:50 PM   #3
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Whoa, can you check the MAF voltage that the ECU is seeing at idle? Any CEL's?

And are you SURE that you have spark on all four? The coil packs (can't tell from video, assuming it is COP) are notorious for going bad on the 20g.
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Old 05-06-2012, 12:04 AM   #4
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They are new gen coils. I haven't REchecked MAF voltage since I got the car started, but I was having issues starting the vehicle initially (ended up being a crank sensor issue). I can unplug each cylinder one by one and notice a change in idle.

I had codes for MAF, TPS, and ECT, but since clearing they haven't come back. The motor with all sensors worked/ran perfectly about a month ago in Scobaru's gc
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Old 05-06-2012, 10:44 AM   #5
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haha wheres superdave when u need him
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Old 05-06-2012, 10:48 AM   #6
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Quote:
Originally Posted by Subbiespeed View Post
haha wheres superdave when u need him
This!
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Old 05-06-2012, 11:47 AM   #7
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sounds like a timing issue. have you made sure all your coils and injectors are pluged in in the right places? ( make sure you didnt swap 1&3 or 2&4).
also was the coil conversion done before you swapped?

could be very week spark also.

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Old 05-06-2012, 11:52 AM   #8
tenchu
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Coil PACKS were converted pre-swap (on my old EJ20G), but the bypass conversion I had to re-do at the time of swap since I replace the bulkhead harness as well.

I have black coil pack connectors going to the back, white front, and grey injector connectors to the back, white front. Copied the order from my Forester.

One odd thing is, if my ecu pin out is correct, when chasing continuity, it seems as though the ecu injector wires are backwards between 3&4 (rear 2 cyl). But I tried de-pinning and reversing them, and the car runs worse.

What would be a cause of weak spark? How could I test this theory?
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Old 05-07-2012, 09:29 AM   #9
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Bueler?
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Old 05-07-2012, 02:01 PM   #10
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for sure a timing issue, sounds like at least a tooth off
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Old 05-07-2012, 02:39 PM   #11
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Timing is dead on. I pulled the radiator/covers/pulley and re-checked it
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Old 05-07-2012, 03:58 PM   #12
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The trouble with motorswaps seems like its always a wiring problem. I never hear anyone who pulls out an EJ20G complaining after they put another EJ20G back in. Its always when some manner of dicking around with the wiring occurs that things go sideways.

I just watch/listened to video. Have you tried starting it without the MAF plugged in? Does it start/idle better without MAF connected?

You said that each cylinder is getting fuel and spark but what is your current fuel pressure at right now? Is the current fuel pump the same as the pump from the donor vehicle?

You had an issue with the crank sensor. Did you check the cam sensor also?
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Old 05-07-2012, 04:01 PM   #13
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from my experience, usually a faulty cam or crank sensor is always a no go. The ecu really really wants those signals.
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Old 05-07-2012, 04:22 PM   #14
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Quote:
Originally Posted by TommyAtomic View Post
The trouble with motorswaps seems like its always a wiring problem. I never hear anyone who pulls out an EJ20G complaining after they put another EJ20G back in. Its always when some manner of dicking around with the wiring occurs that things go sideways.

I just watch/listened to video. Have you tried starting it without the MAF plugged in? Does it start/idle better without MAF connected?

You said that each cylinder is getting fuel and spark but what is your current fuel pressure at right now? Is the current fuel pump the same as the pump from the donor vehicle?

You had an issue with the crank sensor. Did you check the cam sensor also?
Yeah I'm thinking it's a wiring issue as well, just kind of at a loss as to where to start. I'm going to borrow a fuel pressure gauge an check that. Fuel pump is not from donor motor car, it's the same walbro 255 I had with the old motor. I haven't tried starting the car with the MAF unplugged, but I HAVE unplugged the MAF while running, and it didn't seem to make a difference, the MAF IS from the donor car. I haven't checked the cam sensor. The issue I had was an pin mixup at the rear tail connector (cam/crank/knock connector at rear engine harness to bulkhead harness) 2 pins were flipped so 1 cam wire was going to crank and visa versa. I'm not really sure how to test them? But as far as I knew, like eg33GC said, if those two sensors aren't right, you get nothing. Those are the MAIN sensors.
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Old 05-07-2012, 07:15 PM   #15
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Should I be having 12v coming INTO the ECU from the injector? I have 12v on the constant side of the injectors, and 12v coming INTO the ECU at each signal wire (I know its coming in, and not going out, because I unplugged the connector from the ECU and THEN checked voltage). Is this correct?
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Old 05-07-2012, 08:02 PM   #16
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Old 05-10-2012, 10:01 PM   #17
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Ended up pulling the intake manifold, tearing apart the engine harness, and finding some nasty wires, like so:



Fixed those, wrapped up the engine harness nice and fresh, got it run nice and tight up to the intake manifold, and put it back in, car seems to run a bit better, but its still not right:


EDIT: @ 0:43 I shut the car off, and re-started it. I did this because if you notice at the beginning of the video when I first started it, the car ran smooth, then after a few seconds it got lumpy. When I started it the 2nd time, it started off lumpy. It almost seems like the car is flooding. If I pull the fuel pump relay, and crank the car a few seconds WOT to clear out all the fuel, and THEN start the car, it almost sounds like its running normal for a few seconds. Then at the end of the video, I gave it gas, and it died.
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Old 05-11-2012, 01:52 PM   #18
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Update. Got fuel pressure and vacuum gauge hooked up, got ~40psi fuel press at idle, and about 20hg vacuum. One odd thing though is I'm building 0 vacuum at the throttle body nipple, is this normal? Or could it be causing some of my head ache? If so, what would cause this? Here's the nipple in question

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Old 05-11-2012, 02:00 PM   #19
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it may be gummed up, but it should not be the cause of your issue.
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Old 05-11-2012, 02:03 PM   #20
tenchu
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Quote:
Originally Posted by eg33GC
it may be gummed up, but it should not be the cause of your issue.
What about my numbers, I think my fuel pressure is a tad low (2-5psi?) but I'm not sure how accurate the gauge is. I'm not sure what vaccum is supposed to be at?
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Old 05-11-2012, 08:19 PM   #21
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Okay, let me get this straight, someone please chime in. Timing, both cam gears have double lines that should be lined up with each other, so both upper gears lines facing down, both lower gears lines facing up, and the crank sprocket line facing up lined up with line on block. Correct??
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Old 05-17-2012, 03:47 PM   #22
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Quote:
Originally Posted by tenchu View Post
Update. Got fuel pressure and vacuum gauge hooked up, got ~40psi fuel press at idle, and about 20hg vacuum. One odd thing though is I'm building 0 vacuum at the throttle body nipple, is this normal? Or could it be causing some of my head ache? If so, what would cause this? Here's the nipple in question
2 things. First. I believe fuel pressure should be 43psi.

Second. You should be getting vacuum some from that line. You stated you are not. You should try to spray wd40 or brakecleaner through that line to make sure its not jammed up. Do you get vacuum from your other vacuum lines? If it is not jammed up and the other vacuum nipples are the same (no vacuum) then you need to check for leaks. Could be a crap IM gasket, tb gasket or IACV gasket. Fuel supply is determined by metered air. No vacuum usually means a leak letting un-metered air into the engine. The lack of air flow through the MAF because of airleak would cause a problem like yours.
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Old 05-17-2012, 05:07 PM   #23
tenchu
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Quote:
Originally Posted by TommyAtomic View Post
2 things. First. I believe fuel pressure should be 43psi.

Second. You should be getting vacuum some from that line. You stated you are not. You should try to spray wd40 or brakecleaner through that line to make sure its not jammed up. Do you get vacuum from your other vacuum lines? If it is not jammed up and the other vacuum nipples are the same (no vacuum) then you need to check for leaks. Could be a crap IM gasket, tb gasket or IACV gasket. Fuel supply is determined by metered air. No vacuum usually means a leak letting un-metered air into the engine. The lack of air flow through the MAF because of airleak would cause a problem like yours.
the 3 ports on the IM build vacuum, but not much. erratically jumps between 10-20in on gauge, with gauge connected directly to im and all other ports blocked. spraying brake clean around nipples/gaskets/etc makes no change. Timing is on.. I'm so lost.
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Old 05-18-2012, 04:29 AM   #24
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Quote:
Originally Posted by tenchu

the 3 ports on the IM build vacuum, but not much. erratically jumps between 10-20in on gauge.
Factory service manual says that this is a valve problem. The intake/exhaust valves in the head.
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Old 05-18-2012, 09:59 AM   #25
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Quote:
Originally Posted by pmugabi View Post
Factory service manual says that this is a valve problem. The intake/exhaust valves in the head.
do a compression test, and if you have low comp. do a leakdown to find out where.

but I agree, most likely wiring.

look here for injector wiring: http://forums.nasioc.com/forums/show....php?t=2085915

here for coil wiring: http://forums.nasioc.com/forums/show....php?t=1192028

unplug everything and start from scratch. your idle is probably good at first and then turns to crap 'cause you're flooding the motor. when you pull the plugs for the comp test see if the plugs smell/saturated in fuel.

quick edit: you said you "think" you may have spark? check each coil by resting it against the motor/any grounded area and confirm you actually see the arcing in the coil.
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