KZR OBXT Rebuild

[kzr750r1]

Running. Drama free.

Two items stalled first startup.

1) Forgot I pulled the fuel pump fuse. Plenty of crank over so oil was for sure primed.

2) Accessory belts needed a tweak. Too loose on first fire. Both squealed like pigs, all good now.

530 miles in.

Runs smooth. NO piston slap cold start!

Tune on the dyno scheduled for Friday.

Cant wait do get off this base map and get back to boost!

The last break-in run to go see the Mother unit and stop by M45 to schedule the tune.

https://www.relive.cc/view/vXOde3wkjk6

[xt2005bonbon]

Congrats! You're running an AP or BtSsm?

[kzr750r1]

AP is still installed. Kind of bummed I sold the Cobb DP now, kind of.

Will talk to the tuner some more about Cobb going "green" in person.

For now resistor mod in play.

[xt2005bonbon]

Keep a close eye on your fuel trims, synced OCV angles, meeting boost target, and obviously knock. Have fun!

[kzr750r1]

Yeah. Need to rearrange the AP gauge layout. Have most of these in different layouts.

Keeping below 4K right now. Not holding boost if we get there until the new tune is in play. OCV are synced. AFR on this map is 14.5 +/- and knock is not present at this point.

[Max Capacity]

Glad to hear she's running well. Good Job.

[kzr750r1]

Cooling down again after letting the girl drive to school.

Off to go get another jug of oil.

Finding the sweet spot gapping the primitive pan with 3/4" schedule 40 pvc.

May order another with longer standoff. Probably wont.

Will be getting some delrin to create the final form of the spacers to clear the killer B pan.

Edited October 6, 2022 by kzr750r1

[xt2005bonbon]

What will be your oil of choice?

[kzr750r1]

T6 5w40 is in now.

Freaked a little as there was some knock after changing the oil. Seems to be a anomaly cause after a couple ecu resets and just driving normally there was no reoccurrence.

Was thinking it possibly bing the primitive belly pan tapping the oil pan.

I had removed some riser material getting the belly pan closer to final fit.

Still not touching.

If I still ping on the way up to Auburn for Dyno appointment I'll have them drop this oil and see if this is the issue.

 

[xt2005bonbon]

Where did you find some T6 oil??

[kzr750r1]

O'Reilly's had some. Was not on the shelf earlier in the week.

Tuned well. Didn't change the oil. Drove great home.

Set for 15psi. Pushing out 234/272 in the right places.

 

[kzr750r1]

Still getting some DAM drops. Not sure why yet. Going to firm up some suspension and see if the belly pan risers are causing some noise. I'm also considering buying a new DW65C since this one is about 8 to 10 years old.

Need to blast the MAF clean too. Been a few miles there.

Just thinking back what changed in the operation and the only other item was an oil change.

Having a hard time thinking the oil is a cause.

Monitors, I'm going to change some gauges layout to watch the duty cycle on the pump and other items.

Really odd. Did just fine for the entire day after tune. Then once restart and roll back to the house later that night it dropped to .50 then creeped back to .675.

Just reset the ECU. Held 1 for most of the way to daughters school then dipped to .875 and back to 1. Held that for the trip home.

Currently there are some after market lower control arms on it that just make a shit ton of noise after the chassis heat soaks. I have the original control arms and just need to swap the bushings. New front standard spec and the big rear WRX/STI. Was really happy years ago getting rid of the OBXT rear bushing but never changed the sway bars till much later.

Sway bar swap should have been first on the mod list. Totally transforms the car.

[xt2005bonbon]

I would not reset the ECU. How are your long term fuel trims? What numbers are you getting?

[kzr750r1]

Checking into this now. Thanks!

[xt2005bonbon]

As you probably know, make sure all of your long term fuel trims (LTFTs) are all close to zero. If they are on the positive side and large (e.g. +10-15%), then you are in fact running lean which can result in knock. Then again, you just reset the ECU, so some LTFTs may not be well populated yet. In any case, I would first keep an eye on them. You may have popped a vacuum hose or something got loose (i.e. vacuum leak). I hope it's that simple.

[kzr750r1]

Yeah I'll stop resetting. DAM dipped to .875 for a little bit then returned to 1 soon after.

Just about to go out and look at some things. Pull the belly pan (for now). Check for hoses that may have popped.

Clean the MAF sensor. Pretty sure I have a can of that type in the horde.

It's highly unlikely there is a air leak. Gas quality? Possibly? I go to costco nearly every time. Never had an issue like this unless it was a major issue. Hence the concern.

Was reading up on monitors to populate on the guage and the data log.

Cobb is talking about looking at DAM, Feedback Knock Correction, Fine knock learning.

I have one with most all the AF present so between the two clusters may have something to look at later.

 

[xt2005bonbon]

Yeah, check FKC, FLKC. On the BtSsm app, I can have the app beep at me when FKC or FLKC is triggered. Very handy. Not sure if the AP has such a feature. So, what are your LTFT right now?

[kzr750r1]

No not an option on the AP to beep.

Took a drive over the Altamont and back yesterday eve.

Full tank of the same fuel.

Only change this time was I pulled the belly pan (long shot). Did find the MAF was a bit dirty. Pissed at myself I didn't clean it before first start.

No dip in DAM the entire trip.

Reading up on the Cobb site how to be sure what monitors are LTFT. Been a while since I dug this deep into these list of acronyms...

[xt2005bonbon]

LTFT = long term fuel trims. You should have four of those, each covering a specific range of mass air flow. The first one usually covers idle situation, next one very light acceleration, next stronger acceleration and last one close to WOT (and including WOT) type situations. As previously mentioned, you want all of them to be close +/-5%. This means that the ECU is noticing that it does not need to perform large fuel corrections in any of the four ranges. If these are very negative, then you may have a boost leak (i.e. fuel is being removed because all the air that was metered at the MAF did not make it to the intake manifold). Positive is the opposite.

Are you sure you cleaned the MAF and not the intake temperature sensor? The MAF sensor is hidden inside the MAF housing. The little brown 'bulb' that you see on the MAF is the intake temp sensor.

[kzr750r1]

Yes. I hit the sensors in the right spot.

Were about to go drive some more.

Looks like all of these are labeled "learning" so will take a look about the over and under % on my way.

[kzr750r1]

Chugging along ok now. Two runs in no DAM drop.

Going to email a couple driving logs to Travis at Snail and admit I was a dumb ass brining a car in for tune with a dirty MAF sensor.

[xt2005bonbon]

Those numbers are not that bad. Notice that learning range D is zero, most likely because you have avoided pushing it or going into boost. Have you pushed it since the ECU reset?

It is also possible that this learning range (D) has been disabled. I disabled mine.

[kzr750r1]

Yeah. Didn't make a difference always zero.

Trying to be nice to this motor for now. Not flogging it yet.

But have pushed it to 15+ psi for a short time.

Still kicking myself for not cleaning this sensor before break in and tune. 

[kzr750r1]

Still getting a DAM dip from time to time and AF learning is constantly changing. Understood the fuel trims will change. Odd is the changes seem to swing a bunch. Can't find an air leak, yet.

Haven't reset the ECU. Going to let the unit do it's thing.

May order a new knock sensor next and a fuel pump.

Pump is probably 8 years old and this may be the original knock sensor. I can't remember if I replaced it on the first rebuild. 

Thought I found a culprit being one of the turbo heat shield bolts was not replaced. But then NOPE... That's not it.

[xt2005bonbon]

Yeah, make sure heat shields are not rattling. My up pipe heat shield is currently rattling and triggers the knock sensor a lot, but still not enough to decrease DAM.

When you say your AF learning is swinging, how much of a swing?

Personally, I'd doubt your knock sensor is bad. FYI, I recently replaced my MAF connector as, over time, the connection at the MAF may become ever so slightly poor, but enough to affect the MAF reading (e.g. poor ground connection). You may have seen my post in the 'what did you do to your outback'. People keep blaming bad MAF but I think it is more like bad wire connection. In any case, food for thought. You don't have to do that just yet.