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 Post subject: Always lean in closed loop
PostPosted: Mon Nov 20, 2017 4:47 pm 
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Newbie

Joined: Mon Nov 20, 2017 4:12 pm
Posts: 2
Hello,

I use opensource and the tactrix 2.0 hardware to tune my 03 WRX.

A little background:

When my engine seized (due to previous owner not changing timing belt), I replaced the engine with an EJ20X from a JDM 05 Legacy. These are most of the things i've done *before tuning:

• Purchased an 04-05 JDM EJ20X engine. Comes with dual AVCS heads and is almost identical to the USDM 08 WRX engine. Did not come with ECU.
• Swapped any sensors from EJ205 block to the EJ20X as I could. I had to tap and drill a mounting hole for the intake cam sensor. Swapped the cooling lines, plugged the additional cooling and venting hoses that come on the 20X.
• Swapped to clutch (20X is auto) setup. Kept intake risers (TGV deleted) from 20X with the runners+TB from my USDM. These risers are side-feed. Due to my planned upgrades I went with 1000cc side feeds. Had to convert my harness to accept these injectors (took apart connectors and swapped to top feed style connectors). Kept additional sensors in place but not connected (avcs solenoids etc).
• Installed a walbro 255 fuel pump. Kept fuel rails of the 20X (had to adapt slightly to make them fit under the usdm runners)
• Installed all new iridium spark plugs. Kept the EJ20X coils.
• Installed an Forced Performance “Blue” turbo with associated oil lines.
• Installed a new timing belt and water pump, with bearings etc, and new thermostat.
• Installed a mishimoto silicone turbo inlet and associated lines (some of which I had to adapt).
• Migrated my mishimoto TMIC, Perrin short-ram intake, CNT racing 3” bellmouth downpipe, 3” full borla exhaust, lightweight flywheel, up pipe, AEM wideband, stock boost controller

Now, the tuning part..

Once I had all that installed, I went to fire it up. It would crank and fire, but not start. So what I did was copy over as many things from the JDM ECU to the USDM ECU – at which point it started. I remember the fueling and timing maps being quite different. At this point, it started right up, then warms up a bit and dies..

So I kept tinkering with the tuning, and, it appears it is a fueling issue. As, the problem is always the same: less and less fuel (as per my wideband) until it dies. I’ve tried many numbers of injector scaling, increasing latency of the injectors, but, adding too much makes it flood at startup. I’ve gotten it tuned to the point where it starts and idles indefinitely, but, once I add throttle it dies.. If I feather the throttle I can get it to come up on revs but there is audible backfiring and/or detonation from the lack of fuel (I presume). Hence I have not tried driving it. Adding throttle tip-in enrichment helps but doesn’t fix it..

Short story / point of thread:

Basically I believe the car is able to stay in open loop (although it did hunt a bit after flashing), but, as soon as I press the accelerator it goes lean and dies.

What could be causing this?? If I feather the throttle it does come up the revs, but, it's always super lean (17+). I'm running out of ideas and would like to be pointed towards the proper places to look for issues (which tables to modify). Noteworthy to mention this issue was present with the stock injectors and pump on the EJ20X engine.. the issue seems to be something else.. almost like, the air coming in is just way too much.. Kind of like the polar opposite of flooding.

Also winter is here and I can no longer ride my bike to work so I really need to get my car back into shape :( Spent a lot of time and money during the swap.. now it seems like a simple tuning issue. I am looking for a protune some day but I cannot drive it out of my garage in this condition..

Any and all input is highly appreciated!!


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 Post subject: Re: Always lean in closed loop
PostPosted: Tue Nov 21, 2017 5:29 pm 
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Senior Member

Joined: Thu Aug 03, 2006 10:40 am
Posts: 1901
you're going to need to provide logs of stable idle and then of breakup w/throttle.


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 Post subject: Re: Always lean in closed loop
PostPosted: Wed Nov 22, 2017 12:11 pm 
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Newbie

Joined: Mon Nov 20, 2017 4:12 pm
Posts: 2
Okay thanks.

I'm being told by two different, highly-reputable shops, that I should go back to a top-feed system.

They're saying that big side-feed injectors are "junk" and will cause issues such as randomly going lean/rich or misfiring/knocking.

Apparently the only reliable side-feeds unmodified stock injectors.


With this in mind.. I'm (reluctantly) going to listen to them and delete my TGV off the WRX and buy ID 1000 injectors (top feed).

Hopefully my issues are solved with this..


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 Post subject: Re: Always lean in closed loop
PostPosted: Fri Nov 24, 2017 9:43 pm 
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Experienced

Joined: Thu Dec 18, 2014 6:31 pm
Posts: 697
Location: oregon
it's a combination of large injectors wanting low pulse width compensations and sidefeeds being unreliable.

sidefeed is old school, outdated stuff that should be avoided, sorry man

_________________
'03 USDM WRX - EJ205/TD04/FMIC/SD - 2.72 g/rev @ 3950 rpm and 237 g/s @ 6100 rpm


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 Post subject: Re: Always lean in closed loop
PostPosted: Fri Nov 24, 2017 10:37 pm 
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Moderator

Joined: Wed Nov 22, 2006 10:23 pm
Posts: 2428
Switching from 800ish side feeds to ID 1000 top feeds fixed a lean spot for me. Mine was around 5000 RPM if I remember right, but there is definitely some truth behind the strong bias against big side feed injectors. That said, I suspect there's more to this than just the side-feed vs top-feed thing.

Have you tried setting up the ROM so that the ECU stays in open loop full time?

viewtopic.php?f=33&t=7897

It might be interesting to try that and then see if the car behaves better.

_________________
2005 Legacy GT w/ ATP 3076, IWG, MBC, BCS, BC 272, LC, FFS, OMG
Please don't send me tuning questions via PM - use the forums instead. Thanks!


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