Nistune Forums

Hi guys, since about 2 months ago, my s14 EUDM developed an issue out of nowhere it seems.
This happens above 0.5bar of boost and then it starts hesitating, you can hear it bogging, holding back.
It's on a Nistune type 3 board with a stock s14 map.

First i thought it were the coil packs, i've got a vag coil conversion. Keep in mind, this combo ran fine in the past. It literally developed this issue from one day to the other! Only thing that's been off, is the car battery.

So yesterday, i changed to 370z/R35 coil packs. Starting the car is a bit of a pain in the ass.. But i've changed the dwell time to slightly less than double of the nrs in comparison to the sr coils. After it starts, it runs great.

So i went for a drive hoping the hesitation would be gone, but nope.. still there in exactly the same way. It sounds/feels like it's overfueling.

So i took a few logs for the first time. I can see the ECU is thowing a code; "ECU load (TP) limiter reached". It's a completely standard map, the engine is completely stock except inlet and exhaust. Manual boost controller set at 0.65bar. So it's strange...
Also before recording the logs, on the same day, i noticed the knock maps were being triggered. I thought maybe THIS is the issue then. I then (think i) disabled the knock flags/analysis in "Feedback switch 1". Went for a drive, and the knock maps were still being triggered. So i thought maybe this is because of the switch to knock maps...
After a while of fiddling it stopped showing the "ECU switched to knock maps" but it's still bogging.

Next thing i can think of is the MAF sens. Voltage wise, i can see it increase with throttle and speed.

I'm completely out of ideas and hope someone here can help take a look at the log.

You were logging in stream mode or tuner mode?
If in stream mode the knock fuel map is selected as default. Only in tuner mode the knock map is triggered in proper way.

It's not just a fuel system issue is it? The numbers don't look entirely bad (IGN timing, Inj time). What are your AFR's doing? Might just be leaning out.

PL

kamilp1908 wrote: ↑Mon Apr 13, 2020 7:03 am You were logging in stream mode or tuner mode?
If in stream mode the knock fuel map is selected as default. Only in tuner mode the knock map is triggered in proper way.

I think the last log i took was in stream mode. There’s another in tuner mode.

@PL due to it being a completely stock car, i never had a wideband fitted so i have no idea what it’s doing exactly. The narrowband shows 0.7-0.8V when in full acceleration. Which i believe means “rich”

I'd definitely be checking fuel pressure before anything else. This is the most common problem I see on these cars now.

Narrowband will only tell you which side of 14.7:1 you're running. So "rich" can still be 14..4:1!

PL

That’s a fair point. I’ll take a look at the fuel pressure. Thx PL

Hi guys, can't believe i'm still camping with this issue. Tried loads of things in the mean time, and I had to come back to report that I'm still having the same issue.

Things I've tried:
-colder plugs NGK 8 range, car normally runs on NGK 7 range, now back on the old plugs
-370z coil packs, car is normally running on VW 1.8T coils, now back on 1.8T coils
-new fuel pump, was running on oem pump
-installed new z32 fuel filter
-hooked pressure gauge to check on fuel pressure (2.7bar ish on idle, rising rate with boost)
-a working 69F00 maf, idles around 1.2-1.4V, rises with load/rpm
-checked knock sensor wiring, measured +/- 600Ohm which is ok according to FSM
-new NGK oxygen sensor

Things I have not tried
-replace knock sensor; thing is so hard to reach, got a second hand sensor, but it seems knackered as well, no resistance when measured. New sensor is ordered and on the way.
-ecu, i don't have another zenki ecu as most ppl here have koukis

Map
The map that is loaded is unchanged, a stock s14 sr20det map

ECU faults
As soon as i start up, ecu throws the following errors
WARNING: Knock sensor fault - check sensor resistance, signal wire continuity
WARNING: ECU has switched to knock maps
CAUTION: ECU Load (TTP) Max reached. Injection limited. Increase table values

The last warning shows a very good hint at what is going on. Except, i have never changed anything in the past 4 years i've had the car. Always ran the same ecu, same stock mapping, boost is at 0.65bar, so i don't think any of the tables need increasing, specially if it's ran fine like this for a number of years. Could the knock sensor be giving off such an off the chart value that it's throwing it off completely?
Off boost the car runs fine, boosts fine to up until 0.5bar, but will hesitate when it continues to accelerate

Next on the list is to install the wideband and take a log in tuner mode to (hopefully) get more insight

try different boost gauge. I guess you have overboost.

unex wrote: ↑Thu Jul 23, 2020 1:17 am try different boost gauge. I guess you have overboost.

It's not hitting a fuel cut if that's what you're referring to.

It's a mechanical boost controller set to 0.65bar. I can remove it, then it will be back to the factory 0.45bar. I could do that to verify. I don't think my boost gauge is broken..

Can you post your tune file here? Seems like its hitting TTP max injection limit

Matt wrote: ↑Thu Jul 23, 2020 8:07 pm Can you post your tune file here? Seems like its hitting TTP max injection limit

Hi Matt, yes I can upload the tune. It's basically the stock map, but I'll download the one from the ECU to ensure it's the correct one. I've even overwritten the current tune with the base map a few times, and it's still doing the same thing.

Give me a couple of days, my car is at garage that isn't exactly nearby.

Check boost leak , boost leak wil cause AFM read more air than usual, might cause reaching TP limit too.