unicoder

My car was running fine. Cruise/Idle AFR around 14.5-14.7, and WOT AFRs fine at 11.8-12.2 - Plugs were NGK BKR6E gapped at .028

Now all of a sudden, I'm idling lean 15.8-16.5+, cruising crazy lean 16.5++, but WOT is fine. I could only get a 14.7 idle when cold starting.

The only change I made to the engine was run a hose from my valve cover breather to the intake pipe pre turbo, but after the MAF. It had been vented to atmosphere beforehand

I went and got some NGK BKR7E gapped at .030, now my idle and cruise is back to 14.7

But anyways the plug looked leaner than usual see the picture. I know a good plug has a grayish white ground strap, while you have a black ring around the base, but this looked a bit more white than I'm used to

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nisileighty

Stock ECU or is it tuned?

unicoder

RS Enthalpy.

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nisileighty

Every 1000 miles or so my car will act differently. I’m tuned on a power FC, sometimes it idles super high and sometimes it idles rich, but I regularly clean my spark plugs every 1000 miles and it fixes whatever issue almost every time. Your issue could just have been dirty plugs/old plugs and new ones helped.

Kingtal0n

try disconnecting narrowband O2 sensor to disable closed loop thereby eliminating it's a/f correction factor

random extra infos rlly quick
the plug looks good but not enough miles to really tell yet how lean it is. Running lean isn't the problem- running HOT is the problem. You can run all the lean misfires you want as long as it doesn't result with a hot cylinder, think hot plate getting a bit too hot ruining the metal it's made of over time, making it more brittle and crumbly. Yeah you don't like that do ya cast aluminum piston and factory rings. Cylinder washing and running hot will both ruin ring/wall cooperation resulting with either lower compression and tension in the ring itself or problems with cylinder wall finish. Usually none of this stuff is an issue for random factory motors but as soon as you make big power with a small engine you do things to the motor that make subtle issues suddenly become big noticeable issues. For example large injectors and factory O2 delay compensation can be so skewed that closed loop at idle kills the engine completely. Or large injectors plus a maf and atmospheric bypass giving the wash effect that isn't so bad with stock injectors. Larger turbos when the bypass opens and larger injectors to support larger turbos means more cylinder wash.

unicoder

the issue has evolved
- took for a drive, and it started sputtering very bad and reading very lean didnt think id make it home
- came home threw the old BKR6E's back in and it didnt resolve the issue.

car starts fine gets 1 mile down the road and sputters so hard you cant accellerate, but if you feather the pedal or press it harder, it will clear up and take off for a second before going right back into the problem.

Is this Fuel Starvation since it is reading very lean? MAF and Fuel Pump are new, FPR is stock.
- I need to rent a fuel pressure gauge from the parts store to check pressures
- TPS tested good on voltage and resistance
- knock sensor is brand new from autozone
- ISR turbo kit, on ~8psi, new 370CC injectors

Extra info: I have a spare block fresh out of machine shop, in the process of building, but want to have everything else fixed/understood/in order before i throw a new engine in there.

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Kingtal0n

check for air leaks before turbo but after maf

check fuel pressure

my vote fuel pump or air leak atm, air leak is common

unicoder

Ok so I did just add a bung to my intake pre turbo/post maf right before this started. I sprayed it with starting fluid but the engine didnt rev up.

Ill try taking the grommet out and putting some sealant on it and reinserting it

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unicoder

Sealed up the hose I added. No leaks! Didn’t resolve my problem though

I have a spare FPR I’m going to try as it’s free. Then I’ll check fuel pressure when I can source me a gauge

Got the fuel rail off but you know how notorious those two phillips head screws are for being a pain to get off. Will report back shortly

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Kingtal0n

the chance of a fpr being a problem is like 0.001% or less. I mean its down there.

Much more likely fuel pump if there isn't an air leak.

You DID eliminate closed loop right, unplugged the O2 sensor

meh Im betting the "new' fuel pump is giving trouble. Bet the line has a hole or the sock fell off. Or it was a chinese copy and failed. One of that is far more likely, actually double since you were in there recently

JrDarknes

I was having the same issue as you for a while. Spark plugs looked the same and everything man. I was fine WOT but idle i was a bit lean unless it was cold start liked you mentioned.. I cleaned the MAF and it helped a little bit but I drove it saturday night and my fuel pump went out man. I think my fuel pump was dying and I was just ignoring it. Its my fault for being dumb and letting gas get below a quarter all the time and driving it.

It may be your fuel pump, even though it may be new theres a chance it failed or was installed incorrectly.

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FaLKoN240

What brand is your pump? How old is it?

I had a Walbro pump that saw mostly street and some track use, it went to shit after a short 3-year stint.

Have you checked your intercooler piping? Sometimes the piping can work itself loose especially if the weather heats up or gets cold quickly.

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unicoder

The pump is an ISR from enjuku - i put it in 8 months ago, but has seen maybe 2,000 miles of use and never below 1/4 tank

But yes it very well could be the issue - the only reason I was even considering FPR was because KA-T.org speaks so highly about how fast the FPR's die once you boost the KA

I did check for boost leaks - didnt find any

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FaLKoN240

Try changing the pump. I went with Aeromotive. No point in cheaping out on important parts to your build.

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unicoder

Well, I replaced the FPR with one from my OBD2 car. Didnt fix it as previously mentioned.

BUT I am not familiar with bad Fuel Pumps, so here is a video of how it acted today. If i had tried to drive it, it would have just sputtered and bucked and got more lean

The sound isnt very good, about 15 sec in youll notice the shifter start shaking and you can see the engine shaking trying to idle. If I pedal it a bit it can straighten out but goes right back to the problem really quick.

https://youtu.be/fm5hKPVyUbE

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KoukiMonsta

sounds like a fuel problem.

you have a piece of shit fuel pump.

edit: check fuel pressure. you need to collect more data to diagnose this.

double edit: you got one of them chinesium MAFS too?

listen up folks, stop buying cheap ass bullshit for the most critical parts of your motors.

OK, carry on.

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unicoder

Yeah I think I’ve established that at this point. Absolutely tried everything else, pump is the only thing left.

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FaLKoN240

What MAF are you using? I blew my first KA-T using an ISIS MAF

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unicoder

Brand new z32 maf from Autozone. Not remanufactured or anything. Voltages check out on it also! It has been an amazing maf

*edit* still same issue
- car warms up rich 11-12.9
- vacuum steady at -20
- once warm, car has trouble staying 14.7, runs lean all the way to 17.9+++ doesnt die, just sputters
- pedaling it can get it to catch back up for a few seconds then starts sputtering again

time to find me a fuel pump from what I can tell and from the comments here

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unicoder

Welp I'm an idiot.

Do your homework kids...

First time that I have worked on it in the dark, could see the problem instantly, spark plug wire found a better ground... to the head itself.

Issue seems to be resolved. Sorry for not having checked it well enough.

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KoukiMonsta

well, that will explain it. But i would have guessed you'd idle fine and break up under load. Learn something new today..

but seriously, save your pennies for when that fuel pump takes a shit on you.

EDIT: I'm a coil on plug kinda guy, but how did you fix it? re-route wires, new wires, better insulation? what we talkin' bout

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unicoder

Wire #3 was sparking to the head so I took a wire off my spare KA and swapped it out.

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