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Old 09-10-2013, 01:57 AM   #1
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Default Severe hesitation and misfire on WOT

Ok I have been working on tuning this thing slowly everyday by viewing logs and making changes. Got most all parameters good enough to drive, but this WOT hesitation has me confused. I have tried the Accel wizard by blipping the throttle and moving the dots around till it would rev clean from an idle and had to setup the decay for accel enrichment. Just went to drive it and it is still hesitating very badly, but once it stops the car takes off. Weird thing is when I look at the logs it appears that I have the accel too rich since the A/F dips into the 10's. Acceleration without engaging the accel enrichment works fine with no hiccups, but the second it hits the accel it starts hesitating. I posted my log and tune so the experts can have a look and see if there is something I am missing.
Attached Files
File Type: msq CurrentTune.msq (39.7 KB, 61 views)
File Type: msl 2013-09-09_21.06.43.msl (400.1 KB, 103 views)
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Old 09-12-2013, 11:31 PM   #2
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So I think I figured this problem out. After doing a lot of reading in the megamanual and searching through many threads I tried to mess with my threshhold value, and it turns out that has helped a lot. I havnt driven it yet , but just sitting in the driveway blipping the throttle it acts way better.

I had it set at .977 and now its .391 with much lower pulse widths. My high threshhold combined with my large PW was enhancing the problem
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Old 09-13-2013, 12:02 PM   #3
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You shouldn't have issues if you are using the base map and ve analyze live. My buddy had a similar issue and it turned out to be a bad cas connection. When ever he romped on the gas it would get to about 4 k and the car would buck.
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Old 09-13-2013, 11:40 PM   #4
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I did some logs and my signals were all fine. Honestly after I drove it last night it was vastly improved but still needs some fine tuning to be perfect, and according to my logs I think I could tone down the PW adder a little more since it dips into the 10's AFR before settling in my 13.1 targets.


I thought the VE analyze only tuned the fuel table? not any of the enrichment's.
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Old 09-16-2013, 01:42 PM   #5
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I thought the VE analyze only tuned the fuel table? not any of the enrichment's.
Correct.
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Old 09-17-2013, 02:06 PM   #6
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Well a new problem arose a couple days ago. I have been having random hard starting issues for a while and hot idle random misfires that I kinda ignored thinking it was my tuning that needed work. I had the car all warmed up and had loaded some new setting to go for a test drive and went to move the car and it stalled. I tried to restart it and it will crank and not fire. I know its getting fuel because I can smell it, my pressure gauge is showing proper pressure etc....just no spark. I was thinking a coil or ignitor went out. Last night I decided to hook the oem computer back up and connect the vaf to see what would happen, and the car started right up. Hooked the MS back up to check and make sure its still not starting with it. Its not, so the oem ecu is back in till its fixed. Anybody have any idea what happened here? Should I buy a JimStim to diagnose it?
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Old 09-17-2013, 02:27 PM   #7
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You sure there's no spark (i.e., pulled a wire to verify)? You could be too rich to start.
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Old 09-17-2013, 03:16 PM   #8
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I actually didnt verify the no spark condition, just made an assumption. I noticed that as I cranked it over the wideband was reading richer, and then I did flood clear mode till it read "air" and tried again bit it didnt even make an attempt to start so thats another reason I assumed it was spark. Its easy enough to hook the MS back up, so I will verify if it truly has no spark tonight after work. My cranking enrichments have not changed since the tune I uploaded in the first post so if someone wants to take the time to check if they look ok or not would help me out.
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Old 09-17-2013, 03:37 PM   #9
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Quote:
Originally Posted by 300zxrb26dett View Post
I actually didnt verify the no spark condition, just made an assumption. I noticed that as I cranked it over the wideband was reading richer, and then I did flood clear mode till it read "air" and tried again bit it didnt even make an attempt to start so thats another reason I assumed it was spark. Its easy enough to hook the MS back up, so I will verify if it truly has no spark tonight after work. My cranking enrichments have not changed since the tune I uploaded in the first post so if someone wants to take the time to check if they look ok or not would help me out.

I would check each plug on each wire. Are you running COPS? I had a short in one of my lines one time and wasn't getting spark. You can do what I did and ground the plug on the Engine Loop(for pulling the motor) and sit inside the car and crank it looking for spark. If you have no friends to help you out. That what I did cause I have no friends.
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Old 09-17-2013, 04:41 PM   #10
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I am running the stock escort/protege distributor and single coil. I have a calibrated spark tester for GM HEI ignition that should work perfect for checking spark.
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Old 09-17-2013, 11:37 PM   #11
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Weird, I plugged in the MS and jumpered the vaf harness with the spark tester on the number one wire to verify spark and the thing starts up and runs on 3 cylinders like its nothing. Perhaps I have a bad connection somewhere.
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Old 09-18-2013, 10:42 AM   #12
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After the thing started, I only ran it for a good 30 sec and shut it off to try and restart and it was back to doing the same thing until I plugged in the oe ecu. I did in fact test the spark in the no start condition and there is spark, and the short time it did run the wideband was reading in the 10's so perhaps the earlier suggestion of it being too rich in the startup settings is the problem, but unfortunatly I couldnt do anything with the settings because the laptop battery had died. Another day I guess. I would love to get thing running and driving on MS as smoothly as it does on the oem one some day.
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Old 09-18-2013, 06:39 PM   #13
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Regarding your initial problem, what are your spark plugs gapped to?
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Old 09-18-2013, 06:55 PM   #14
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A few things:

1. My guess is that you are flooding the engine with the Crank Settings. Probably OK when you are 100% cold, but with any heat in the engine enough fuel is vapor that you are too rich. Good explanation of Crank Settings/After Start Enrichment/Warmup Mode, etc. here: https://www.miataturbo.net/megasquir...ng-more-62872/

2. When the WBO2 first starts, it has to warmup also. During this time period, an Innovate sensor (not sure what you have) reads 10:1 -- which is not a real reading. Note that if you fail to fire or misfire, there will be plenty of O2 in the exhaust, so you should be reading lean no matter how much fuel is present. The O2 sensor senses just that . . . O2.

3. Steve's plug suggestion is a good one. In addition to gap, look at color and wetness.

4. When you do finally get it going, change your oil. You've probably got dilution.
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Old 09-18-2013, 08:24 PM   #15
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Quote:
Originally Posted by sixshooter View Post
Regarding your initial problem, what are your spark plugs gapped to?
Stock replacement plugs in Iridium #3764 and stock gap @.044"

Quote:
Originally Posted by hornetball View Post
A few things:

1. My guess is that you are flooding the engine with the Crank Settings. Probably OK when you are 100% cold, but with any heat in the engine enough fuel is vapor that you are too rich. Good explanation of Crank Settings/After Start Enrichment/Warmup Mode, etc. here: https://www.miataturbo.net/megasquir...ng-more-62872/

2. When the WBO2 first starts, it has to warmup also. During this time period, an Innovate sensor (not sure what you have) reads 10:1 -- which is not a real reading. Note that if you fail to fire or misfire, there will be plenty of O2 in the exhaust, so you should be reading lean no matter how much fuel is present. The O2 sensor senses just that . . . O2.

3. Steve's plug suggestion is a good one. In addition to gap, look at color and wetness.

4. When you do finally get it going, change your oil. You've probably got dilution.
1: I actually found that thread earlier today and will be comparing my enrichments to what I find in there.

2: I have a PLX DM-6 SM-AFR and it actually reads stoich at startup, plus I had the key on before crank and start at least for 1min so the sensor was already warmed up and reading "Air"

3: I will certainly check when I get a chance to play with the car again.

4: For sure, especially since its still on the engine break-in oil with almost 200 miles on it anyway.
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Old 09-18-2013, 09:06 PM   #16
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Gap plugs down to ~.028 like everybody else and your spark blowout under boost should go away.
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Old 09-18-2013, 09:10 PM   #17
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lol 10afr + stock gap = you're gonna have a bad time
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Old 09-18-2013, 09:23 PM   #18
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I am not boosted. N/A at 10.3:1 compression
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Old 09-18-2013, 09:28 PM   #19
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oh my bad, thread changed directions it seems like and didn't read all of it.
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Old 09-28-2013, 03:00 PM   #20
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Well I finallay got around to loading my new settings in and I did have some settings and my enrichments were pretty far off, but I am still not able to start the car. Verified spark and fuel, so it must be either a settings issue or the MS is bad. I have been running the last couple weeks on the stock computer and it runs fine.
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