blab7

I have an 01 nb2. .5mm overbore so 1863cc, 725cc injectors, no more vics flaps in intake manifold and polished intake and exhaust runners. I have ms3 pro pnp. virtual dyno says about 148 hp and 145 torque. I have been going through some tuning troubles and could use some help. I am running very rich which I have been told is safe, my idle is a little high at 1200 rpm, and my overrun fuel cut is not always kicking in. lastly the car likes to die in idle when the ac is on. I appreciate your help. i will post the data logs and tune msq. both tunes are examples of warm starts, and the end of the drive-home-from-canes.msq is where the ac idle kills the car. this is at the very end.

blab7

If anyone has any tips on how to improve my tune, i would really appreciate the help. I want to learn how to do this myself

curly

iTrader: (25)

Your target idle is 1230 due to your target of 930+300 for AC idle up settings. You have decent AFR targets and at WOT and idle you're close to them. If you're rich in the cruise and partial throttle areas, tune the fuel table.

Towards the end of the "drive home" log, the car got quite hot, 230clt and 155iat. I'd look into that asap. Fan should have come on at 190 and been able to control it.

blab7

Just looked over the car, the fan comes on at 190 and I verified that it does actually come on. looks like the car is getting up to that dangerous temp at idle, i have the stock radiator could that be the problem? also good to know that my afr targets are good, but i was told by another forum that my fuel ve table is richer then it should, i make 14 mpg when pushing the car pretty hard.

redursidae

The stock radiator should be able to keep your engine temperature fine at idle. Something is wrong with your cooling system if that number is accurate and I would start by making sure both fans are working when the AC is on and no bubbles in the system. Your VE numbers seem in the ballpark to me, but there are some basic settings that should be fixed, such as your injection timing and fuel pressure system (assuming you're still stock fuel pressure and returnless). Overall certainly not a bad start but needs to be tuned. The VE table doesn't seem finished.

As far as your idle, it's a lot of little settings combined. Here is a list of items you should address, but not exhaustive.

- VVT is active at idle. Make sure it isn't, otherwise it will cause issues
- Change you idle control from Last Value to Initial Table and tune that correctly. It will make the idle more accurate and stable
- Your idle ignition is removing too much timing to reduce RPM, yet not using enough timing to increase it. Make your idle control more accurate before using this feature
- Set your idle ignition target closer to 12-15 degrees, instead of 20. It seems you had the right idea, but went too high. This will let your idle ignition control to have a wider range of adjustments, and also make your idle valve have more say.
- The reason the engine stalled was because the idle valve didn't open enough before the compressor kicked on. This is a combination of what I said above plus the compressor delay being too long for how quickly your closed loop idle reacts (the valve was already closing before the compressor started). But mainly, your idle valve bump was too small. Look earlier in the log and you'll see it needed 40% DC to achieve target, but right before the compressor started it was only at 28% DC. That wasn't enough air to let the engine idle.
- Set your Idle-Up Min RPM to 800 RPM so that the compressor turns off if the engine is not idling high enough.
- Maybe only bump your idle 150RPM when AC is on. I think 1230RPM target is a bit high for a warm engine.

redursidae

And this being an NB2, your idle valve frequency should be closer to 500Hz. That may help the response of the idle valve too.

sixshooter

iTrader: (12)

Fans will recirculate hot air if the undertray isn't sealed from the bumper mouth to the radiator.

Fans often slow as they age rather than stop completely.

I added an inline delay relay for my fans so there was a 3 or 5 second gap between the compressor engagement and powering up the fan. This helped the propensity to stall with the big Spal fan but may be a useful trick for you as well.

Increasing the wiring capacity from the battery to the alternator, fuse block, and the grounds helped with stalling also. It actually allowed the battery to help catch more of the initial draw instead of so much work being suddenly placed on the alternator and that load slowing the engine.

It was an experimental platform for me.

blab7

come to think of it, i have probably half of the possible screws on my undertray. while i take the rest of the car apart to fix the water pump and cam seals I will remove and replace all the broken bolts. also I think there is a way for megasquirt to delay the ac comp/ fan activation time. I will update after all things have been fixed.

blab7

Redursidae, that is a lot of great information, thank you. some questions i have are)
1) how do I turn vvt off at idle? is this done by just changing the vvt table to have a value of zero in the idle area of the map?
2) not sure what setting I need to turn off to stop the idle ignition problem you mentioned.
3) how do i set idle ignition target? looked at tuner studio and couldnt find any setting that was setting idle ignition target to 20
4)idle valve is set to like 80% now and my idle is around 2k rpm. guess i just need to tune the fuel at this point now.
5) I was told my injector dead times are bad and I should get those tuned correctly. I have EV14 725 cc injectors from FM's website and I used the deadtimes listed in their page for these injectors. do you think the dead times are wrong based on my tune? if so how do i calibrate dead times? i was told to get my idle afr to the same place as the idle afr target and then bump up the target by 1 point and see if the afr actually changes.

redursidae

1) In the VVT target table se the lowest breakpoint to 1500RPM, and set the column to 0. Change the Min Duty % until the VVT angle and target match in TS with the car at idle (0 angle). Unless I'm missing it, MS3 doesn't have an RPM based lockout.
2) Under Startup/Idle > Idle RPM Timing Correction Curve. Click the 3 dots on the graph and change the timing reduction values. I don't recommend you turn it off, instead tune it correctly to advance/retard timing based on RPM error to stabilize the idle.
3) Startup/Idle > Idle Advance Settings. Click the 3 dots on the graph and those are your target idle ignition values based on Load. I set these to a flat advance and let the ignition control adjust accordingly.
4) That's too much idle RPM and valve duty. Set the idle targets to something reasonable and tune the idle control to match it. Note my recommended frequency near 500Hz. Unless you have some radical cams the engine should idle happily at 900RPM without AC and about 1000-1100 with AC.
5) Although your deadtimes are likely imperfect, the VE numbers seem about realistic to me. That process for checking deadtimes is valid, but I wouldn't change one full point, instead I would start at 14.0 AFR, then vary rich/lean by 4% (13.44, 14.56 respectively), and watch the EGO Correction. If the correction is near +-4% then your deadtimes are close enough. Do this on a fully warm engine otherwise you have even more variables messing with the test.

There are lots of variables that affect the VE number, such as your VVT being active, your fuel pressure settings, and the highly incorrect injection timing, so fix those first. Your problem isn't one big thing, but a lot of little settings that affect each other