Callin all Nistune pro's!

[Jagstang]

Hey Nico, today I got the Nistune type 4 board installed and tuned by a local shop. They've tuned a bunch of S13 SR's with nistune in the past, so I'm not really questioning their install. I just had a question since I'm experiencing a weird problem.

When I shut the car off, and leave it off for a little bit, then turn it back on, the check engine light pops up, and the car idles strangely. When this is happening I keep my eyes on the wideband, and it shows 15.0 FLAT for a good few seconds, then it moves up and down to 15.1, then maybe 15.2, then back to 15.1, etc.

When this happens, I just shut the car off, and re start it, and the check engine light always goes away, and the car idles perfect. But just a while ago, I turned it off and started it again, and it was still doing it. I turned it off a second time, and restarted it and it finally went away.

I was just wondering if this is a common problem with nistune boards? If not, do you think it's a mechanical problem? Or the shop didn't install the board properly? The check engine light came up right before leaving the shop, and the tuner got super confused and couldn't understand why it was idling weirdly. He shut the car off then turned it on, and it went away. He took it for a spin with me to see if there was any problems, but everything was working great.

By the way, the board was installed to control the AFR's, it used to run very lean on the stock tune, but with the nistune now, when I boost, it's at 10.5-11

If you guys can help me out, I would greatly appreciate it. Thanks in advance.

[Razi]

Strange...
I'd check to see if the board is loose.

[Jagstang]

Strange...
I'd check to see if the board is loose.

If it was loose, wouldn't the check engine light flicker on and off as I go on bumps with my stiff coilovers? But yea it's weird. The car has been sitting for 1.5 hours, I bet if I go to start it right now, it will give that check engine light with the uneasy idle. Happens every time so far.

[asoomal]

10.5 on stock boost is too rich bub.

[Jagstang]

10.5 on stock boost is too rich bub.

I'm boosting at 10 psi, bub.

[asoomal]

Still too much, should be around 12.

Edit: BTW, if the board was loose, your car would die at the same time as it would "disconnect".

[95_240]

What code is the ecu throwing?

[OutToWinPAHC]

10.5 on stock boost is too rich bub.

I'm boosting at 10 psi, bub.

It;s still on the rich side.... like a toyota

[Jagstang]

Thread Update:

What code is the ecu throwing?

When I brought the car in, they tried using nistune to read the check engine light, but the program wasn't connecting to the ecu. So long story short, my ECU got f***. Luckily the shop realized they were at fault, and they went ahead and bought another ECU. This new ecu seems to run far better than my old ECU.

My old ECU would run lean as soon as I give it gas under boost, or just during mild acceleration. Now, when I punch it, it's around 14.7-15 under 3000 rpms, and as soon as I pass 3000 rpms, it starts to periodically drop to 10 (which seems about right since the stock tune is normally very rich). So next week I'll be going back to have the nistune board installed on the new ECU, and have them tune the 300zx MAF sensor I just picked up.

It's still on the rich side.... like a toyota

Alright, what should it be at? Asoomal told me that it should be at 12, anything richer, and it can wash down the oil from the cylinder walls, and get gas in the oil.

[OutToWinPAHC]

12.1-11.5 under boost closer to the 12.0 mark, 14.7 after warm up idle.

[asoomal]

My brother's 3S idles at around 16-17 when fully warm, and 13-14 when cold.

Under boost it's 10:1...cause Toyota.

IMO.

Go lean as possible on idle without any misfires.

16:1ish is good for idle.

Remember, an internal combustion engine running on gasoline offers best torque at around 12.6:1. This isn't possible with boosted engines though, unless you're using some high octane fuel with direct injection.