MS3 Power loss/boost cut

[ZetaEpyon]

Lately I've been experiencing a pretty significant loss of power in my 2007 Mazdaspeed 3, but only under rather specific conditions:

• Any gear
• Fairly heavy throttle (not necessarily WOT)
• 3000-3500 rpm
• Possibly cold temps?

Essentially, I can accelerate hard all I want, but when the engine hits 3000rpm, power just dies, almost violently. If I stay on the accelerator, the moment it gets to 3500rpm or so, the power is back in a massive surge. From everything I can tell (I have a bluetooth OBDII adapter), this seems to be the boost cutting out entirely over that rpm range, and then coming back in. If I simply accelerate more lightly, like in normal around-town driving, it'll sail right through the same rpm range without anything to notice.

What I can't figure out is why this is happening. It's not related to the engine being warmed up; the first time it occurred, I had been driving for about 2.5 hours on my way home from out of town, so the engine was plenty warm. I moved to pass someone, and the power dropped out. It does seem to be worse when it's cold (both engine and air temp), but warming up doesn't completely eliminate it. It's not really an issue in my daily drive to work and back; I'm not crazy and ripping around town near WOT. At highway speeds, I can just downshift to keep the rpms above that range if I need to pass. Still, I'd like to actually fix the problem, rather than just working around it.

Aside from that issue, the car is running like a champ. OBDII isn't showing that it's throwing a code of any sort, so I'm sort of at a loss. Any ideas on what I might look at?

 

[MotF Bane]

..

 

[iamwiz82]

What kind of boost are you seeing? Does the MS3 have a boost limiter? My MSM has an electronic solenoid that will dump boost if the ECU sees boost levels that are too high.

 

[ZetaEpyon]

Using Torque (Android app) to monitor it via OBDII, it seems to generally peak at 14-15psi, but that's at higher rpm. I can check where it's at right before the 3k rpm line later today.

Boost is artificially limited in 1st and 2nd gear, but just at a lower pressure. So it certainly has the ability to dump boost, but would that really happen at 3k rpm? If this was happening at much higher rpm, that seems like it would make more sense to me.

 

[exar333]

I don't have a lot of help to offer, but cold weather should actually be helping your power. Cold air = awesome for a turbo engine (assuming you are not talking REALLY cold temps....).

 

[ZetaEpyon]

Right, and normally it does.
This is something different entirely, as far as I can tell. If it was really cold (sub-zero temps), I might just write it off as that being the issue, but it's been a really mild winter so far (46° today).

 

[jlarsson]

Does it feel like it shutters a bit when on the accelerator?

If so, it could be the knock sensor. There might be a TSB out for it (I can't find it at the moment), but I think it's mostly due to the gas we have here in the states. I get it occasionally in my MS6.

 

[ZetaEpyon]

I kept hard on the gas once or twice to see if it would push through that rpm band, and the car shook a lot. I haven't done that since, because I don't want to cause serious damage by being stupid without knowing what's going on.

The fuel is an interesting idea, I can't say for sure, but I'd guess I've only noticed the issue since stations (presumably) switched over to a winter blend. The gas I usually get is ethanol-free 91 octane (highest available here).

 

[NutBucket]

If its happening all of the sudden then it may simply be a bad tank of gas.

Had that happen in one on the Subies. Engine knocked enough that the ECU cut boost completely. Once I got the bad gas through, everything was back to normal.

 

[exar333]

Have you checked for any vacuum leaks? It could be a simple pressurization issue, one that would be a lot cheaper than anything relatd to the turbo/transmission.

BTW - didn't notice your location until now. Yeah - this winter has been really mild (MN here). Great for driving though; nice chilly air to feed the turbo.

 

[ZetaEpyon]

If its happening all of the sudden then it may simply be a bad tank of gas. .

It did appear pretty much out of nowhere, but has persisted through several tanks of gas (from gas stations hundreds of miles apart, even).

Have you checked for any vacuum leaks? It could be a simple pressurization issue, one that would be a lot cheaper than anything relatd to the turbo/transmission.

Have not checked for vacuum leaks. Never done that before, but a quick google search seems like it shouldn't be all that difficult.

 

[Zap]

Had similar problem with my 2007 Mazdaspeed 6. Massive power hitching (almost like fuel cutoff) at around 3000-3500 RPM. The engine is almost identical to yours.

The (mostly) fix for my car was a new EGR valve. If you're halfway decent at wrenching, you can probably clean the existing one. There's a link to some instructions in that thread. Speaking of, I should probably update the thread now that I have just over 4 months on the new EGR valve.

 

[DaTT]

Have you been on Mazadaspeed forums? Sounds like its dumping boost for one reason or another. Does the boost drop to zero in that range?

Have you tried slowly accelerating to 3000rpm with out any boost, then step on it to see if it will start to boost at that range?

 

[ZetaEpyon]

Had similar problem with my 2007 Mazdaspeed 6. Massive power hitching (almost like fuel cutoff) at around 3000-3500 RPM. The engine is almost identical to yours.

The (mostly) fix for my car was a new EGR valve. If you're halfway decent at wrenching, you can probably clean the existing one. There's a link to some instructions in that thread. Speaking of, I should probably update the thread now that I have just over 4 months on the new EGR valve.

Wow, the symptom you mention in your thread is pretty much identical to mine. Maybe I'll have to give the EGR valve a cleaning this weekend, doesn't seem like it could hurt.

Have you been on Mazadaspeed forums? Sounds like its dumping boost for one reason or another. Does the boost drop to zero in that range?

Have you tried slowly accelerating to 3000rpm with out any boost, then step on it to see if it will start to boost at that range?

I haven't, but maybe I should, looking at Zap's link. I have tried stepping on it shortly after 3000rpm after getting there slowly, and it still flops.

 

[LTC8K6]

It does sound EGR-ish...

 

[ZetaEpyon]

Of course, since posting this thread, I have not been able to replicate the issue one single time. I wonder if that might be due to the exceptionally warm weather over the last couple of days though, we'll see. I'll probably still give things a look this weekend...

 

[JCH13]

EGR could very well be it.

I'd also check your BPV, grease it if need be.

Also, I'd check to see if you're getting any knock retard. When was the last time you did plugs?

 

[ZetaEpyon]

The plugs are still the originals. Even though the car is 5 years old, it's at a little less than 50,000 miles. The heavier maintenance schedule in the manual (Schedule 2) indicates that they should be replaced at 60,000, so I suppose it's certainly possible that they're starting to go a little early.

 

[JCH13]

The plugs are still the originals. Even though the car is 5 years old, it's at a little less than 50,000 miles. The heavier maintenance schedule in the manual (Schedule 2) indicates that they should be replaced at 60,000, so I suppose it's certainly possible that they're starting to go a little early.

Many MS3 owners find that plugs every 25-35k helps a lot, or maybe it's that they switch to a plug better suited to the driving (hotter or colder). I've got a set waiting to go in when the weather isn't cold as shit.

 

[punjabiplaya]

www.mazdaspeedforums.org

check for leaks, check if EGR is gummed up, check if plugs are fouled up, are you showing tons of KR (knock retard) during those revs? Some guys were also having compression issues on cylinder 1 or 3 (i can't remember which).

 

[SJP0tato]

Do you have any modifications to your car? Or is it 100% stock?

 

[ZetaEpyon]

It's stock. I had the Cobb SRI on it for a while when that came out but ended up selling it and going back with the stock airbox.

Hopefully, I'll have a chance to investigate some of this stuff this weekend. I'd thought I could do it tomorrow, but I forgot that we have a company event, so I can't really be without a car for the day.

Also, now that it's gotten cold again, the hesitation is back. So, the temperature does at least aggravate it, if nothing else.

 

[iamwiz82]

It is sounding more and more like electronic boost cut to me. My MSM does the same in the cold because of my mods. Maybe your wastegate actuator is funky?

 

[hopbang802]

I realize this thread is a little old but I was wondering if anyone has had any luck in solving this problem? It is exactly what's happening with my 2007 ms3 right now.

 

[Joe T2020]

I also have been getting a violent complete power loss. Only in the rain however, every other condition is fine. Does anybody have any ideas?