Empire087

Ok so ive been troubleshooting My car for the last 6-7 months, Basically ive had an issue that over a short period of driving:Generally 5-10 minutes my car will start a lean cut out and slowly get worse until its a 2500 rpm cut and it will sometimes climb over that. It happens at around 4k rpm, but it comes on after some spirited driving sometimes faster than others but always comes. Essentially I will get on the throttle for a few times and do a few good pulls then the car will start just going max lean all the time when throttle is applied. The first bit of it is at 3700-4000 rpm, and its it will lean bog Max at 18 afr ---. Then it will get to the point where you can barely give in any throttle without it cutting out Like 1/16 of the pedal. It will always happen, sometimes it takes longer than others. However if i turn the engine off and on the problem will simply go away for a short period and come back. Also to note the car runs rich 10.5ish afr at wfo, and cruises at around 13. So far ive tried/replaced: ecu(Mine is blitz access with custom rom R32mt, One i have is a rom tuned for an r32 a/t)No difference, Another cas NO difference, Brand new plugs, Clean/taped coil boots, Different Ignitor NO difference, Another Maf NO difference, 98 sentra cts, 98 ka cts both no difference, New 255 fuel pump(2), Different Fpr(both tested good), multiple fuel filters, checked injectors all 14ohm, checked tps at .46 idle/around 5.0 wfo, and deleted my cold idle valve. The weird thing is if i restart my engine(Key all the way off) and turn back on the problem goes away for a little while but comes back as before. The car also starts like s***, not quite sure why, im pretty sure i wired the start signal in right.
Video below
https://www.youtube.com/watch?v=9kWXgqNlED4

Ive been struggling with this for the last 6 or so months i really need some help!

baube

do you have your o2 still plugged in? I had a similar problem with a tuned ecu. I had to unplug the o2 and everything was fine then

Empire087

Well ill certainly give it a try, damn near tried everything else lol.

Empire087

Well that didnt work either.

lgsr20swap

Does ur wideband have a failsafe?? Maybe the wideband is fucked??

Empire087

Oh it bucks and falls on its face, its certainly going lean. Its an aem wideband which is like 3 weeks old.

cotbu

Stop driving the car like that, and when you make videos turn the phone vertically.

I can probably help you, but I'll be requesting videos and I like full screen videos, lol. So pull codes and report back. If you don't want my help, tell me to go screw myself!

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Empire087

Usually i take proper videos, that was just a poor timing one. The thing is im throwing no codes, its showing up a code 55.

cotbu

Your ecu could be bad, try throwing a code.

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Empire087

It will indeed throw a code, i unplugged the tps and it came up with a code 43 yesterday. Also tried an auto r32 ecu as apposed to my blitz access mt r32 ecu and it told me code 54 for no auto signal.

boosted23

Have you checked your mass air flow for anything on the wire or for issue? Check your tubing to make sure it's sealed and check the waste gate vacuum line.

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Empire087

The previous owner did kind of a janky job wiring the mass air flow extension. I redid the wiring from that point with shielded wire.

baube

did you checked the solder inside the maf? they tend to crack sometimes

Empire087

Resoldered both at the connection

Empire087

Someone has to know something.

boosted23

You should really try another maf. Maybe even go 300zx maf.

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cotbu

I agree if he's not sure what mafs the ecu is tuned for, try the most popular. Most likely its tuned for a stock mafs or z32.

Op if you have a way to dump the bins I can tell you what mafs its tuned for, and tell you if you have the correct injectors.

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Empire087

I have tried another maf, i have two j60s. The guy that sold me the motor set told me it was tuned for stock injectors, and stock maf.

cotbu

You're trying to diagnose a problem with your car, you can't go back and say things like the previous owner did a janky job on wiring the mafs, then be like he told me it was tuned for.... or it ran good when...
all that must go out the window if you want to fix your car or just ask the previous owner for help! I would prefer you go back as close as possible to stock, because we know how stock should function. Does that make sense?

I forgot you said you be at this for 6/7months, time to be proactive.

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Empire087

Ok, so the j60 was stock, ive tried two. I will see if i can find a z32. I have been tearing this car apart trying everything under the sun so far. The injectors are stock.

How would i go about checking the ecu bin? As of now, i have no means to do that. But i also have that other r32 A/T ecu which brings the same problems. That was tuned for stock maf/stock injectors.

I was told the engine ran great when he had it, and as ive been tearing into the motorset/wiring harness ive been finding things i didnt like. so ive been fixing them. Ive been being proactive with this the whole time. Im simply running out of potential fixes to the problem. I made the list of things ive tried/changed so far.

cotbu

2500rpm limiter or breakup seems and or problems around there are usually mafs problems, and they come with codes. so let's start there.

your wiring for the mafs, it doesn't need to be shielded wire, but if you use shielded wire the shield cannot touch the signal wire at all because the shield is grounded. verify that and repair if necessary.

post a better video of your gauges and rpm, or data log while the issue is happening.

if you have a consult port wired up, cable and software you can data log through it and also download the bins in the ecu.

I'm thinking mafs issue, so I'd start with the wiring, visual. Then open the ecu, follow a pin out and check continuity from ecu pins to mafs plug. against ground as well, making sure there's no tone from signal to ground. make sure the ecu will throw that mafs code, on whichever ecu you believe works.

How do the plugs look after this?

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Kingtal0n

If I bought a car with an RB and right away it seemed to be leaning out, I would

A: immediately tune-up the engine and fuel system, check fuel pressure during WOT

Next,
B1: switch back to stock ecu/maf/injectors if still using the stock turbo
B2: if using an upgraded turbo, it must have a stand-alone, add fuel manually, or
B3: If using an upgraded turbo and a rom-tune, invest in a stand-alone (cheapest is PFC for $500~ for that engine used) *OR* [Raise fuel pressure / Install a piggyback] for spot adjustment as a temporary band-aid to bring the air fuel ratio back. A combination of both would be ideal. For instance if the car is going 15:1 at 15psi of boost and my base fuel pressure is set to 43.5psi, I would raise it to 58psi and that should bring the a/f down some (closer to high 13's) - if it did not, I would suspect the fuel pump is the culprit. If it does, then proceed to add the rest of the gas with the piggy back (until you can get a stand-alone). The piggyback/fpr solution is only reliably viable at "low"(5-12psi) boost, with close-to-stock size injectors, on a mostly stock engine.


Another test to see if your fuel pump is the culprit would be to create a boost leak somewhere and go WOT. IF the air fuel comes back rich then you see you have the gas available from the pump. If the engine stays the same lean ratio / maf cuts then you have your answer (fuel pump output)

cotbu

It seems like he eases into throttle and it still happens, maybe if he disconnects the waste gate, or tries a zero boost test, we could further eliminate some causes.
If this was happening arount 4/4500rpm I would say fuel/fuel pump related.

OP post a picture of you engine bay too.

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Empire087

Will do tommorrow, i did pull my injectors/rail to make sure there was no junk in the rail or injector screens. Im also going and renting a fuel pressure gauge, so i can check that out.

Empire087

Was pouring here all day, so i wasnt able to go out for a drive.

here the pic of my engine bay

boosted23

You really need an air filter on your maf

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Empire087

I literately tried it to see if maybe the air filter was causing problems. I just havent put the filter back on.

cotbu

so........., is that how the engine looks now and how you've been driving it except for the filter?

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Empire087

yup, except i replaced the hoses on the pcv and put the filter back on the other port.

cotbu

Yeah cause the hose missing from the intake manifold side, could have explained the whole thing, but running a filter on the port isn't the best setup, even through everyone does it. The other issues I see are wiring. If you're not having hard starts or rich idle then maybe some of its OK.

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