Help with my MSM - Limp Mode

I was at the track on Thursday and I was adjusting my boost with a manual boost controller. I was running great at 10 PSI, but decided to dial it back some to see how it would feel. I turned it back up and for some reason my boost shot to 15 PSI during a run. When that happened my car shut me down by dropping to 4000 RPM and only allowing me 3-4 PSI of boost.

I dialed the boost back down with my controller, but no matter where I put it its the same thing. 3-4 PSI and once I hit 5000 RPM a soft rev limiter kicks in and I can't go any faster/higher.

Yesterday I unhooked the battery for an hour hoping that would reset the stock ECU and that would solve the issue but no luck. Any ideas? My car is slow as X-Mas right now, and I am at a loss.

I was wondering if my boost controller broke and it putting to much boost out and the ecu is constantly going into limp mode. Does anyone have a boost controller I can borrow to test that theory?

Or maybe i need to do something else to get it out of limp mode?? This is my first turbo so I'm really not too experienced.

Thanks

Sorry nobody could help with this. I would try the mazdaspeed forum and see if they can help. Other than that, a call to trackdog racing or Flyin' Miata may help. Good luck.

Resetting the ECU entails holding the brake pedal down for around 15-20 seconds with battery disconnected and then drive readies have to be done on earlier models. As for the MSM, no clue. Sharpie's suggestion is where to start. Keep us posted...

I got it figured out. I guess I upped the boost a little too much. It blew the Throttle Body Inlet hose off. LOL. I bought some new clamps and got everything strapped back down and all is good. It wasnt the ECU at all but I wasn't putting any pressure into my throttle body.

I plan to replace the intercooler and pipes, as well as my blow off valve in the next few weeks. That should allow me to turn things back up. After that I'm looking to install a new downpipe. Lots of fun projects coming up.

miataturbo.net

stop being cheap and get a electronic controller

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Originally Posted by jeff_man

miataturbo.net

stop being cheap and get a electronic controller

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Hey supercharger guy, electronic vs. manual boost control has nothing to do with this. It has everything to do with small a/r turbine housings. For the record, I'd never spend a cent on EBC.

Gonna say, an ECU can't make a turbo produce less boost than the wastegate setting. Unless there is some kind of controlled boost leak produced especially for this purpose, which I have never heard of any OEM doing. If the MSM wastegate is 7psi, you can't be limited to 4psi unless there is a physical problem, which is almost always a boost leak (could be a bad turbo, etc, but is more than likely a massive leak in the plumbing somewhere).

My best advice to a new turbo vehicle owner: Get or make a boost/vacuum tester, learn how to use it, and use it every time you change the oil especially as the car gets older.

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Originally Posted by mr brg

Hey supercharger guy, electronic vs. manual boost control has nothing to do with this. It has everything to do with small a/r turbine housings. For the record, I'd never spend a cent on EBC.

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hey i mean electronic so it doesn't have to do guess work with how many turns = how much boost. I'm giving you the benefit of the doubt that your way smarter about turbo stuff thin this guy and that you know how to adjust your boost properly.

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Originally Posted by Rob®

Gonna say, an ECU can't make a turbo produce less boost than the wastegate setting.

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it pulls a butt load of spark so your turbo wont spoil in return

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Originally Posted by jeff_man

hey cock sucker guy, i mean electronic so it doesn't have to do guess work with which way to turn = how to adjust your shocks.

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Fixed that for ya. :)

Quote:

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Originally Posted by Rob®

Gonna say, an ECU can't make a turbo produce less boost than the wastegate setting. Unless there is some kind of controlled boost leak produced especially for this purpose, which I have never heard of any OEM doing. If the MSM wastegate is 7psi, you can't be limited to 4psi unless there is a physical problem, which is almost always a boost leak (could be a bad turbo, etc, but is more than likely a massive leak in the plumbing somewhere).

My best advice to a new turbo vehicle owner: Get or make a boost/vacuum tester, learn how to use it, and use it every time you change the oil especially as the car gets older.

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You are right on. It was a massive leak in the plumbing. Ill look into a tester. Thanks.

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Originally Posted by Electro

hey cock sucker guy, i mean electronic so it doesn't have to do guess work with which way to turn = how to adjust your shocks.

Fixed that for ya. :)

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I blame the teachers for that one, Trey (aka cock sucker) told me turn them from soft to hard and john gave me turn counts from hard to soft. i still have to translate click count between the 2. yet i ran 1:31s around hallett with them set wrong.

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Originally Posted by jeff_man

it pulls a butt load of spark so your turbo wont spoil in return

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Eh, I'd be surprised if it pulls *that* much timing. Every factory turbo car I've ever owned has a limp mode that pulls a ton of timing but still only reduces boost to the wastegate setting. But those were all early-mid 90s cars, so the MSM could very well do what you're saying. I'd still be surprised.

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Originally Posted by Rob®

Eh, I'd be surprised if it pulls *that* much timing. Every factory turbo car I've ever owned has a limp mode that pulls a ton of timing but still only reduces boost to the wastegate setting. But those were all early-mid 90s cars, so the MSM could very well do what you're saying. I'd still be surprised.

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i drove magmas car and it pulls so much spark it feels 50hp slower. he's running the powercards so the stock ecu freaks out every so often and acts like a soft limp if you run it hard.

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Originally Posted by jeff_man

I blame the teachers for that one, Trey (aka cock sucker) told me turn them from soft to hard and john gave me turn counts from hard to soft. i still have to translate click count between the 2. yet i ran 1:31s around hallett with them set wrong.

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Just busting your balls. He he... Hell, I still have to ask Wags when I set up for the track.

That's the point of a limp mode...My Z's limp mode was literally ~50rwhp less than stock power. But it still would hit wastegate boost pressure, that is my point. All the other factory turboed cars I had were the same way.

But yeah, I know the MSM ECU is screwy on a few other things, so I guess I can see it happening like that. Still seems odd to me.

Regardless, that wasn't the problem, and it's fixed now. So this whole conversation is moot.