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1.6L Miata stumble and hesitation problem

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Old 09-11-2013, 01:17 AM
  #41  
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Also, did you click the MS2 tuning link?

It provides good info on grounding issues which I haven't ruled out as part or total cause of my issues....
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Old 09-11-2013, 11:23 AM
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AFR will spike anytime there is a misfire for any reason because O2 is present. Definitely a side effect.
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Old 09-11-2013, 11:38 AM
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That sounds like boost cut. This is a hard **** down/hesitation and if I keep flooring it it just keeps resetting.

Car used to pull hard until the reset but now it breaks up then resets so it's a decaying problem that has gotten worse over time
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Old 09-12-2013, 10:35 AM
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Unplug the TPS and try it
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Old 09-12-2013, 11:47 AM
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I'm very hopeful for the above two suggestions of unplugging the TPS and upping the boost cut.
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Old 09-12-2013, 11:16 PM
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An uneducated thought occurred to me, have you considered a faulty or randomly failing coil or perhaps your wiring to the C.O.P.S..?
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Old 09-12-2013, 11:50 PM
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I tried loading new firmware but couldn't get it to work. New coil drivers and map sensor are on the way. Tomorrow those will get installed, I will unplug the tps and try again. If that doesnt work I will replace the cops, I have a full extra set and have been trying them as I go, not scientifically. Next step after that is to ohm the wiring harness to check for loose wires/resistance. (The whole harness is brand new high grade wiring, engine harness uses an automotive grade bulkhead connector, all crimp connected with brand new connectors to each sensor.)

Like I said, everything did work, so something in the system must have failed
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Old 09-21-2013, 08:46 PM
  #48  
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So, I installed a new map sensor (map daddy 4 bar) in the ECU and loaded new firmware (MS1 029). I rebuilt my old map and the car won't idle. Do I need to retune because it's a new map sensor or should my settings still be good?
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Old 09-26-2013, 12:52 AM
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I figured out the problem. Getting AEM, that will fix it. AMIRIGHT?
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Old 09-26-2013, 08:54 AM
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Originally Posted by theshdwconspracy
I figured out the problem. Getting AEM, that will fix it. AMIRIGHT?
no.
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Old 10-07-2013, 11:26 PM
  #51  
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So I guess here are updates, not that anyone has a clue any more but maybe someone will chime in with something I've missed.

I had two sets of toyota COPS. I put all the original cops back in the car and another GOOD CAS and it worked. briefly. I drove it around town, boosted it (1.4bar), did burnouts and beat on it. Took it to the track, drove 5 laps and it started to reset and break up again.

The original cops are loose and can lose connection by popping out which is why I swapped them out. Soon as I put a new (second set) coil in it would make the problem worse.

It would work for half a lap with the original ones in and then start resetting and stumbling again.

Problems/Solutions

I was having alternator charging issues, the over driven 140A alternator creates a lot of drag and slips if the belt isn't super tight. I've been tightening it to help my problem.


I've also never installed the 10k MFD Capacitor in my system. However I'm not entirely convinced this is my problem, because a week worth of beating on the car (after it was built and tuned) and I didn't have a single problem while tuning or at the track without this Cap. The wiring is all brand new mil-spec.

All my sensor wiring runs through a bulkhead quick disconnect, idk if that is creating any kind of problem, but it is an automotive grade connector and shouldn't cause that kind of problem.


Ideas? I did decide to ditch the Megasquirt (Found out it was an MS1) and I bought an EMS4. I want to make sure that I can fix this problem so that my new ecu turns out to be a worth while purchase, and not an expensive toy in the middle of a headache problem.


Thanks for your help if you read this whole thing
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