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Old 11-18-2015, 01:25 AM   #1
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Default Power/Fuel/Something Cutout, MSPNP2 V1.3

Any help on the following issue is greatly appreciated.

First, about the car a little bit. The chassis is a 92 miata with all stock wiring. I completed a 1.8 swap in the usual manner, using the 92 coils, sensors, everything electronic. Prior to the swap I had the car running on a V1.3 MSPNP2, but not tuned. The 1.8 motor is essentially a 99 motor, but with stock 94 low compression 8.8:1 pistons. The motor has the FM2 Turbo kit on it. I have ID1000 injectors and I am using a 99 fuel rail with this (http://s29.postimg.org/bnr9b1hqf/photo_7.jpg) type of stock fuel pressure regulator bolted to the end of the rail for the return line. Currently running 7-8 psi with the turbo kit.

Now, a little bit about what the car is doing. The car runs fantastic at the moment under just about all scenarios. Pulls well, sounds good, everything seems great. There are 3 issues:

The first issue is, under full throttle (and from what I can tell, ONLY under full throttle) the car BUCKS, HARD at 3800 RPM (and above, just keeps bucking). The car will rev out under partial throttle and not quite full boost, about 4-5 psi if I modulate the throttle. I have read around about this and there is one post up about using the MAP sensor off the same line as the FPR. I haven't tried exactly that, but I have tried 2 different positions on the manifold for the MAP, one at the front of the manifold and one at the back. Doesn't change anything. From what is happening in tunerstudio, it seems to be a fuel cut.

The second issue is just terrible throttle response. This problem is caused by me being garbage at Megasquirts and most things engine tuning. I just wanted to ask some advice on this one.

The third, again, I think me just being a scrub with Megasquirts. So the car idles pretty good in neutral, but once you put it into gear, the idle goes up to about 1600 RPM. It's the weirdest thing, because it wasn't doing this AT ALL at first, and then just started randomly doing it. Pretty clueless on that one.

I have attached a data log of the buck and my current tune. The data log may be a little long, but it should be fairly obvious when I hit it under full throttle and get it to replicate the problem. If I need to I can do another data log.

Again, any advice is greatly appreciated. And I apologize if I did something really dimwitted regarding the fuel/power cut. This is the first time I have put a 1.8 in a 1.6 chassis.
Attached Files
File Type: msl EngineBuck4000.msl (2.07 MB, 88 views)
File Type: msq CurrentTune.msq (108.9 KB, 64 views)
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Old 11-18-2015, 01:45 AM   #2
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150KPA fuel cut.

Needs more AE. MAP based sucks, use TPS.
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Old 11-18-2015, 01:49 AM   #3
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When you say AE are you talking about accel enrichment? And really?! I thought MAP based fuel was supposed to be the best for fuel. So I should use TPS input instead? I do have the VTPS from the 99 motor hooked up and functioning. Where is this setting to swap this for the fuel?
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Old 11-18-2015, 01:56 AM   #4
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Throttle based AE is best for acceleration enrichment because it is more precise at predicting desired acceleration, whereas map based sucks and has pseudo input lag.

Map x rpm based fueling is the base for throttle or map rate-of-change percentage based accel fuel enrichment, that is not what I meant to suggest you change.

The settings are under time based accel enrichment, your tunerstudio might look different so just look for accel enrich or similar. There is a slider to blend MAP and TPS based AE, I suggest full TPS instead of full MAP as you are using now.

The lower you can set the starting TPSdot value without undesired noise hitting and triggering enrichments at wrong times, the better it will behave.

I also suggest removing the 90% fuel decel amount, set it to 100%. It can cause lean jerk problems unless you are aware of it and drive around it.
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Old 11-18-2015, 02:30 AM   #5
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Awesome! I can definitely try this stuff. Where is the 150KPA fuel cutout? I tried to find that and I couldn't. (BTW I am not sitting in front of TunerStuidio as I do not have that computer on me)

Also, do you have any idea what's going on with the idle bumping WAY up when I put it in gear? I know there is a neutral switch on our transmissions, so I assume it's something to do with the tune.
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Old 11-18-2015, 02:50 AM   #6
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Under boost control settings, which is under boost/advanced on my TS.

Your tune is using warmup idle valve control, something so primitive I'm not sure how you managed to get it doing that. Most people don't wire up the neutral switch for that purpose, they do it for launch control. I don't know what's been done with your MSPNP, but I doubt it's wired to the neutral switch. Even if it were, your tune isn't set to use closed loop idle so there's no need for a neutral switch to lock out closed loop...

Have you ever read anything in tunerstudio? I suggest you at least open all the windows and read them top to bottom.
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Old 11-18-2015, 11:56 PM   #7
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Well, I can only apologize so much for being novice at ECUs and for engine tuning not being my thing before it loses all of its meaning. I did search around for these settings and I did scavenge on TS, to include searching all of the menus and settings. My problem, with TS is that for someone like me, the terminology and adjustments to the settings are NOT intuitive for a person who doesn't know what they are doing. The documentation for operation is a LITTLE bit better but not much. That's why I turn to the forums.

As far as for the idle control, if I could, I would pay someone to set that crap up. On my last car it took me FOREVER to get it to stop fluctuating out of control using the closed loop settings, and now you're saying this one isn't even set up for that. I will have to mess around with the settings when I get back into town tomorrow. It WAS idling fantastic before it started doing this weird thing with the neutral switch.
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