KZR OBXT Rebuild

[kzr750r1]

We were at 0 for a bit last I was looking at 1C. It's been -7 to 5%. Depends on ambient temp and how it's being driven.

Daughter is a more conservative than my foot. DAM seems to settle quickly if it go's south, back to 1 after a few miles.

1A looks to creep + after running and idling a bit.

Took it out so my daughter was not distracted going to school this morning.

Coming up on my next OC and will dig more. Have not seen a loose hose or any issues with vac lines, intake, TB hose... All look good.

May be time to build a smoke rig.

[xt2005bonbon]

I can't remember if you can pull a 'learning view' table with an AP, so you can see at one glance in which conditions it is knocking.

Looks like this on romraider. I am referring to the 2D table below.

Edited October 24, 2022 by xt2005bonbon

[kzr750r1]

Pretty sure I'd have to log the monitors to get that data captured.

Will keep an eye on it.

Just about time to drop the oil again. We have been driving it.

Had the daughter unit drive a back road loop this weekend, I ride the bikes there from time to time. She needs to work on steering input and breaking. Good place to get a feel of the car. Yesterday was her first non supervised drive to school. Car is back without damage.

[kzr750r1]

Well this was an eventful day. DAM dropped to .125 for the entire drive over to a checkup for the daughter unit.

Right out of town blech....

Ran a little rough. Surging here and there.

Didn't see any issues with fuel trims. Lots of fine knock activity.

Reset the ECU to clear it's head as I may have some bad gas and need to avoid Costco all together for a while.

On the way back P2138 put me in limp mode... Finally something to help isolate this weirdness. Frustrating.

Reset again, code cleared and ran fine for a while... Dipped to .5 again. Back to 1 then dipped to .875 buy the time we parked at home.

New pedal assembly 36010AG021 ordered. Also going to get another DW65C to drop in for good measure.

Seems to be at low RPM high gear that all of this is happening.

[Max Capacity]

FWIW, I seem to recall my Tuner recommending that I get the AEM fuel pump over the DW65C. He had better luck with the AEM. I think the AEM340 is the new one, I got a AEM320 back then.

[kzr750r1]

Thanks Max. Yeah I considered changing but didn't want to enter another variable. Were not going for peak HP here.

Had to just walk the daughter thru another limp mode reset. Same code P2138. Hoping it shows up this week.

[Max Capacity]

May I ask, who you use for your Tunes ?  I see your in North Calif.

[kzr750r1]

Snail using M45 dyno.

[kzr750r1]

New throttle pedal assembly installed. Reset Idle procedure complete.

Input is much smoother.

Should have done this a long time ago. I was suspecting there was an issue based on input of the off idle input has been erratic for a while.

Although it never failed 100% figuring the potentiometers had worn out and began skipping the first few mm in pedal travel.

Pump is here too. Waiting till December to put it in as a preventative measure.

Trying to make one change at a time for now.

[xt2005bonbon]

How much was the part?

[kzr750r1]

In total 189ish shipped from Heuberger. Worth it. Looking forward to driving it some more tonight. Was a blast yesterday hearing turbo spool. DAM stayed at 1.00 do far.

[xt2005bonbon]

Good to hear!

[kzr750r1]

Still getting a dip to .875 from time to time, in town driving only so far. Going to head up to the foothills this week.

Well see if this settles or needs more attention.

Putting off the pump install for now but if this keeps up I may put it in service sooner.

[xt2005bonbon]

Did you verify that all heat shields are nice and tight?

[kzr750r1]

Yeah. I don't have the lower one on. At one point I did have a screw missing on one point of it.

 

[xt2005bonbon]

no heat shield on the up pipe? Mine is rattling like crazy... Needs some welding.

[kzr750r1]

I have not reinstalled the lower shield under the turbo. Top is on. May install again and put a blanket (in stock) under for added thermal protection.

Had to turn back yesterday and park it for now. Ordered some new Ignition coils. Mainly since these have 255K on them. Have never replaced them since I bought the car from the stealership.

It seems to go through some conniption fits just cruising down the freeway. Feels like it's missing at that point.

I'm going to look at everything over the weekend and make sure there are no cracks in the IC or vac leaks.

Double check the pinout of one IC connector I replaced. Make sure I wasnt' distracted and miss pinned it. Doubtful, but worth a double check.

I feel this layer is good since the fuel trims look in range. Still worth a check.

I just realized there is an OB section now... Mods if you want to move this go ahead.

[xt2005bonbon]

Personally, if fuel trims are fine, then you should be free of vac leaks and stuff like that. Another thing: how are your VVT angles? Are they always in sync? Forgot to ask that before.

[kzr750r1]

Last I looked they were in sync. Both are new. You're on the same page with me, fuel trims are in line, vac leak is doubtful.

So there has to be another fault.

New coils show up Saturday. Well know more soon. Will also confirm the plugs didn't loosen up, those were new too.

Edited November 23, 2022 by kzr750r1

[xt2005bonbon]

OK.

Regarding coils and plugs, if they were bad I would think random misfire count would show up. Have you been carefully tracking this parameter for each cylinder? That's the annoying thing with the AP: you can't view lots of things at once like BtSsm. Their screen is too small. Below is an example of what I have running at all times on my phone (or tablet) while driving. I have other gauge setups too but this is one of them. I know it is a lot but a lot of these gauges are important to track IMO. It's a Subaru after all .

Edited November 23, 2022 by xt2005bonbon

[xt2005bonbon]

Also, you should avoid resetting the ECU and try to keep track of the cells in which knock is being consistently registered. This may give you an indication of whether or not the tune needs adjustment.

[kzr750r1]

At this point I'm just a wee bit frustrated and running out of ideas. Looking like fueling issue of some sort???

Had a half tank of gas. Filled it up at Chevron with some injector cleaner. Still getting knock at low throttle input driving. Always in the lower 15% input.

I pulled the IC off while doing an OC to see if there are any issues. Nope. 3K on this motor now.

So at this point I'm going to order another MAF. Need some Ball Joints anyway. The Movetech LCA make a lot of noise after heat soak so not sure if this is translating to knock, possible, new bushings I have in hand. Will be talking to a shop to press these in place today. Will also see if they have a scanner we can use to drive test and see if injectors are not firing correct.

Will also be sending a log to Snail to see if he see's anything he can adjust.

For now burn out the rest of this tank. Fill back to half for a comparison and if no love after replace this pump.

 

[xt2005bonbon]

I doubt your MAF is bad.. Post another LV.

[kzr750r1]

Ran ok if I didn't dog it around town last night. Drove in Manual mostly and no dip in DAM yet.

Will drive this gas out some more before bugging the tuner.

Two things I have changed on him are.

1) cleaned the MAF after the tune.

2) put the stock mufflers back on, had Nameless mufflers on during tune.

Once this fuel is out of the systems well see if it settles down before the next major move.

 

Edited December 1, 2022 by kzr750r1

[xt2005bonbon]

Trims still within specs but a little negative nonetheless. Looks like you have not really gone into boost since trim D is 0. But I think you mentioned it always remains at 0, which means your tuner disabled trim D (I did the same for one of my cars).

So I guess with an accessport, you'll never be able to "pull a learning view" table similar to what I posted on an earlier post (see below).

That's too bad cause it helps you see at a glance where the ECU has learned to remove timing due to knock. It can give you a good indication over time whether the ECU consistently pulls timing within a given range of engine load/RPM. Without seeing such a map, it is quite difficult to troubleshoot the issue. You'd have to log.