SAFC removed for Nistune, now running rough.

[denonic]

Hi all,

First post and sorry it's a long one!

I installed a Nistune type 4 board in my 180sx Type X a couple of days ago and am just getting familiar with it.

Before soldering it all in, I had been running a Z32 MAF using an Apexi SAFC with the hotwire settings 2 in 6 out, and no other corrections. The car was running fine so I decided to go ahead and get the Nistune in there.

I figured I'd start it up with the SAFC still all wired in to see if it would start fine before pulling it out and doing a MAF change operation in the software. It started first go and idled normally so I pulled the SAFC out since I figured a MAF change operation was doing a similar thing to the hotwire settings.

Removed all wiring and neatened up all the ECU wires from the splicing. Then it was onto the software MAF change operation. I put the car into accessory without starting it, connected to the consult port and had it all running in the software, did a MAF change operation and uploaded the image to the ECU and since I did nothing else, went ahead and burnt it on.

I started it and although it did start, it was sputtering and was having a hard time idling steady. I tried to pedal it but the RPMs would dip toward zero and want to stall so I'd let off and let it start to stabilize again. By stabilize I mean still bouncing around and sputtering between around 500 - 900 RPMs but not stalling completely. Eventually once coolant temps reached around 70 degrees it started to idle a little better.

I thought maybe it was just a cold start issue so I let it warm up for another 10 minutes and take a short slow drive to see if everything was ok. For the most part it seemed good. AFRs were at ~14.7 at cruising speeds. Looked good. Then when I was stopped at a light, it seemed like the car was going to stall again, dipping and bouncing again between 500 and 900 RPMs. So I decided to pedal it again. This time it did work and brought it back up to a ~1000-1100 RPM idle. But then the AFRs started to get really rich. Around the 9s even when stopped at a light. Once I was driving again it was sounding very lumpy and occasionally the car would jerk and I'd see the tacho correlate with a sudden RPM dip.

I stopped for a bit so the car could rest. Temps were fine and nothing was coming up on the consult when I checked. I babied it on the way home and it made it back without going rich again.

I'm currently on the stock 370CC injectors and have 740CC JECs to go in before heading to a dyno, but wanting to sort out this MAF issue before putting anything else in.

Any ideas? Was I completely ignorant and missed something? I did read through several of the documents on the website regarding MAF change. Did I absolutely need to play around with the K Constant?

I still have the old MAF and connector and I'm half tempted to throw that back in to eliminate the possibility of it being anything else.

If anybody could point me in the right direction that would be amazing. Would ideally like to have the injectors and MAF in so I could just roll into the dyno and let them get started on a proper tune.

[denonic]

I went ahead and switched back to the old SR20 MAF.

Idle was still intermittently rough but good for the most part. Was also having a hard time connecting to consult. Seemed like each time I hit the connect button the RPMs would drop, and then the consult would disconnect and before stabilising to 800-850RPMs again.

Had a look and battery was running low.

Took it easy but went for a long drive to recharge the battery a little bit. Car was running ok and was even able to give it a bit at some on ramps and it pulled fine.

It did have 3 instances of RPM dipping when stopped at lights for a split second. I've attached an image of the log at the moment it dipped. Not sure if it would lead to any sort of conclusion as the consult would disconnect at that exact moment.

signal-2021-12-27-165656_001.png

(137.42 KiB) Downloaded 5383 times

On the final minutes of my drive back, it didn't have any issues at all.

Has there been any instances of issues connecting to consult with a low battery?

[denonic]

Ok so it looks like the z32 maf was not the problem at all.

Maybe something to do with my nistune install... bad soldering maybe? Will give it a check later.

The car will still have a sudden rpm dip while idle, and more concerningly, sometimes during acceleration along with the car jerking.

After this occurs the car will run incredibly rich (~9 AFR) until ignition off.

Next start its back to normal until the next time it rpm dips.

Is this a limp mode symptom?

[Matt]

This time it did work and brought it back up to a ~1000-1100 RPM idle. But then the AFRs started to get really rich. Around the 9s even when stopped at a light. Once I was driving again it was sounding very lumpy and occasionally the car would jerk and I'd see the tacho correlate with a sudden RPM dip.

We really need to see the logs from this to determine what is going on. You wont get any consult errors, unless something is shorted/open

I'm currently on the stock 370CC injectors and have 740CC JECs to go in before heading to a dyno, but wanting to sort out this MAF issue before putting anything else in.

Usually a good idea, but it might be worthwhile doing the 740CC injectors. I'm not sure if you have feature pack or not on the board. What part# in the software in the top panel?

The Z32 MAF makes K high, but 370>740CC will bring it back down to almost factory values

Without knowing if your grounds are good, and the voltage fluctations with the MAF (from a log) it is difficult to know if that is a problem

Did I absolutely need to play around with the K Constant?

You may need to adjust this. Do you have the TIM parameter with Feature Pack?

Was also having a hard time connecting to consult. Seemed like each time I hit the connect button the RPMs would drop, and then the consult would disconnect and before stabilising to 800-850RPMs again.

Charge your battery, double check grounds are clean and secure. Log battery voltage and have a look at that. The screenshot shows 13.7V which looks good

Consult doesn't like noise in the cable, from injector/coil feedback or other EMI related issues. It will garble communications

Nistune installation either works or doesn't (ECU limp mode). So it wont be that. If you had the board fitted with the SAFC at the start, then it wont make any difference

Running super rich, no consult and check engine light are indicators for SR20 of limp mode. Did you see this?

[denonic]

We really need to see the logs from this to determine what is going on. You wont get any consult errors, unless something is shorted/open

Unfortunately it stops logging as soon as the RPM dips.

Usually a good idea, but it might be worthwhile doing the 740CC injectors. I'm not sure if you have feature pack or not on the board. What part# in the software in the top panel?

I do have the feature pack so the injectors would ideally adjust TIM.

Charge your battery, double check grounds are clean and secure. Log battery voltage and have a look at that. The screenshot shows 13.7V which looks good

Charged battery and reflowed all the solder points on the nistune install and did a thorough clean of the jumper. Haven't had issues again since but haven't driven it all that much again so will try again on the weekend.

Running super rich, no consult and check engine light are indicators for SR20 of limp mode. Did you see this?

No check engine light, but running super rich and consult dropping were 2 big symptoms happening mid drive.

Will take it on a good drive on the weekend and see if the issues happen again. I have a feeling maybe one of the solder points wasn't too clean and was intermittently disconnecting causing it to go into limp mode.

[Matt]

Check engine light is the big indicator. I assume you have CEL when you first ignition on (before starting engine?) just to confirm?

If you are getting comms dropping, that might be a separate electrical issue (noise)

The boards either work or they dont. When they dont work, and you are limp you get all three (CEL+no comms+rich fixed pulsewidth)

[denonic]

Check engine light is the big indicator. I assume you have CEL when you first ignition on (before starting engine?) just to confirm

All the warning lights turn on during ignition on so the bulbs are all good.... unfortunately what I've found out is that the cluster in the type X along with a bunch of other S13 clusters (depending on model year and market) didn't have a dedicated CEL... What I thought was the CEL in mine was a catalytic converter overheat light and on USDM Type X cluster conversions on the 240sx S13 they resorted to using this catalytic converter light as a CEL during rewiring.

I didn't get a chance to drive the car last weekend as it's parked in my parents garage 40 minutes away and they were in COVID so I'll update again when I do get around to it.

[denonic]

Was able to take it for a drive on the weekend and worked fine without dropouts. Looks like it might have been my poor soldering of the daughterboard cable and/or jumper. Looks ok since reflowing it all with better solder.

I've attached a log of the last drive but didn't have any issues so will look to swap the z32 MAF back in and see if anything changes.

[Matt]

Okay good to see you got on top of it

[denonic]

Z32 Maf installed again, now have 740cc injectors in also. Injector and maf size updated in the software.

Has a hard time on first start. Cranks fine but won't catch idle and stalls if I don't pump the accelerator. Played with after start enrichment but didn't seem to help all that much. After it manages to idle it'll be fine the rest of the drive but at stoplights idle will sometimes dip down to around 500-600rpm momentarily before recovering to ~800rpm.

Not sure if logs will help to find the issue but I've attached a few short ones just in case.

Anything look off Matt?

[Matt]

Looking at this without a tune file. Battery voltage is dropping on decel. Might want to check wiring and the battery itself (orange)

2022-05-27 12_18_03-Nistune [HCR32 SKYLINE (RB20DET) (Version_ 4)].png

(71.37 KiB) Downloaded 3356 times

On decel we are seeing MAF not dropping, so TP increases and so does fueling.
Here drop to about 500rpm before it recovers. MAF voltage stays at 1.2V. I'm not seeing any idle indication. Is the TPS setup properly? It should show TPS idle when TPS returns to the voltage recorded at crank. Not seeing neutral switch either

[denonic]

Hey Matt,

Thanks for that. I've got the car in a workshop doing some engine work and will get them to do a full retune and check the MAF after the engines done. Will check out battery wiring if the voltage is still dropping on decel when I get it back.

TPS I had set up and was seeing about 0.5V at idle and was showing TPS idle if I recall correctly.
Neutral switch was sticking and needed some play on the shifter to get it to register. Didn't think it affected too much but will get another ordered in when I can find some in stock.

Cheers!

[Matt]

Neutral switch not so important, but idle is so make sure that is fine, and MAF voltage should sit around 1-1.1V around idle