04 MSM, MS3 PNP Pro 3. Idle and Pulsewith Issues - Miata Turbo Forum -Boost cars, acquire cats.

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Old 04-29-2016, 06:40 PM   #1
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Unhappy 04 MSM, MS3 PNP Pro 3. Idle and Pulsewith Issues

Hi All,

My name's David Adams, I don't post much (if at all) but I do a lot of reading and searching. This issue, however, has my tuner and I perplexed. He says this is something he's only seen with Mazdas so I'm posting here in an effort to help get to a fix and I'll try to be as consise as possible.

My car is an 04 Mazdaspeed Miata, mods currently are wideband, 10.6 pound flywheel, clutch, intercooler, intake, exhaust, boost at 12 pounds and megasquirt MS3 PNP Pro. What my car is doing is very strange so I'll try to be accurate. It has the (seemingly typical) warm/hot restart issues whereas it doesn't want to. It also, even when cold, will sputter and sometimes die if you hold the clutch in after starting. The only way it'll "catch" idle is if you let the clutch out immediately after starting.

The car also hesitates when getting on the throttle from idle. Of course, the harder and quicker you push the throttle from idle, the more likely it is to konk out and die. Very strange.

It also, and I think this is related, won't enter launch control. Come to a stop, clutch in, 1st gear, hard down on the the throttle, it'll just sputter and it won't go above 500RPM. At all. Even if you slowly rev up to 4k then put your foot down, it'll just sputter itself almost to death.

Lastly, when "revving down" from any engine speed (for example when coming to a stop at a redlight), if you leave the clutch depressed, the engine will cut out.

My tuner, wanted me to mention that the pulsewiths with the clutch OUT are "normal" at around 2.5ms. However, with the clutch DEPRESSED, they jump to 8ms. I have no idea what that means (maybe someone can explain that to me).

I hope I didn't ramble on too much while still giving all information needed.

I've posted the MSQ tune and a quick datalog of me going clutch in, clutch out, trying to start with the clutch held in and starting with the clutch out. Let me know if I need to post a driving datalog as well

Thank you all so very much and please pardon my ignorance. Though I am a SysAdmin, this vehicle stuff perplexes me to no end.

Thank you all again!

David Adams
Attached Files
File Type: msl startup and idle issues.msl (2.66 MB, 38 views)
File Type: msq WideBand MSM.msq (251.8 KB, 17 views)
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Old 04-30-2016, 04:44 PM   #2
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Pulsewidth is how long the injector fires. It's the final voltage the MS gives out after it uses your tune, including fuel table, WUE, AE, etc. 2.5 is pretty normal, 8 would be pig rich. Your "tuner" most likely just needs to "tune".
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Old 04-30-2016, 05:34 PM   #3
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I noticed your MAP signal was very poor and initially assumed your MAP line was pinched. However then I noticed that the lags are turned way down. This motor would respond like poop. Start with the lags at 90. (higher numbers = better response)

Launch control is turned off in the tune... Either way, you shouldn't be leaning on a 2-step if the car runs badly.
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Old 04-30-2016, 09:41 PM   #4
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Last edited by stefanst; 04-30-2016 at 11:22 PM. Reason: Lack of comprehension.
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