Getting some kind of "CUT"

A

Alexsered

Member
:
2007 Mazdaspeed3 Gt
I've been getting some kind of "cut off" in the engine when it's cold outside and i'm WOT at 4-redline RPM's. I just replaced spark plugs with denso's, and thought it was going to fix this issue, but it didnt.

What happens is I will go WOT and when I get to the higher RPMs, the engine for a split second cuts off either fuel or something, my BPV releases, and than everything re-engages and I'm back to WOT. It is very "jerky" when that happens, and only really when I'm WOT. I know we have boost cut in cold weather, but I don't think it's that. It really feels like I let off the gas completely for a split second and than hit the gas again.

The only thing I can think of is when I replaced my stock BPV, I started boosting a little higher when referring to my boost guage, and maybe I'm boosting too high and the ECU is freaking out? Any idea's? I'm probably going to go to CP-E and talk to Lou and see if he knows of any ECU issues like that.
 
Welcome to my hell! I am very well modded and have a map clamp to hide my boost from the ecu and i still cut like crazy. This car pisses me off. If there isnt a known fix for this soon i am getting rid of my ms3. It pisses me off that bad!
 
when you get rid of it, I'll trade you for your K04 and snatch that black Forge from ya too! :D
 
ecu is too high and it is freaking out. I think iwth the stock flash, if it sees over 18 psi for a second or two, it will cut and continue to cut.

Too bad the CPE flash didnt raise the boost cut limit.

It's probably really cold weather? In time...the ecu may adjust and compensate, but it might not either.

ghetto fix would be map clamp and trick the ecu into thinking you're at a lower boost level

proper fix would be get standback..or cobb AP. the SB will actually use a map clamp also, but then it has its own boost control to control it. AP will control the boost and raise the boost cut limit itself in the ecu.

Only other fix is to just avoid going WOT or wait until it warms up or taking off some mods:(
 
tru-boost said:
Welcome to my hell! I am very well modded and have a map clamp to hide my boost from the ecu and i still cut like crazy. This car pisses me off. If there isnt a known fix for this soon i am getting rid of my ms3. It pisses me off that bad!
Click to expand...

Might wanna consider the Cobb AP before considering it a lost cause.
 
The AP is a lost cause just as much as the car itself is! Look at all the mods you have and how weak your car dynoed. Hell my car with very similar mods on stock ecu dynoed at 300/340. People see more of this cutting when their car makes more power..... FACT! The reason most AP cars dont cut is because they dont make any power! I am convinced my car can beat any AP equiped car out there, fuel cut and all!
 
If these dyno were done onrhe same day that explains the gain righ there. To accurately do dyno comps on a flash devie you have to dribe several hundred miles inbetween to let you fuel trims and everythin else get settled to where they will be normaly operating. If just roll in do a dyno, flash and dyno again of course you will show gains because you ecu is no longer compensating for your mods and you will run slightly leaner. I could show you very similar results in dyno runs just from unhooking the battery and resetting the ecu. Just the way ecu's work.
 
Ah but that's the methodolgy I may not have explained in those posts ... here were the steps:
1 - I put the car on the dyno with the stock tune and reset the ECU
2 - do 2 dyno pulls
3 - flash the Cobb tune which resets the ECU
4 - do 2 dyno pulls

I never even rolled the car off the rollers ... can't get more fair and comparable than that,
 
welcome to small turbo syndrome, get a new turbo and enjoy the fun of full power up to 7k rpm :)
 
tru-boost said:
Welcome to my hell! I am very well modded and have a map clamp to hide my boost from the ecu and i still cut like crazy. This car pisses me off. If there isnt a known fix for this soon i am getting rid of my ms3. It pisses me off that bad!
Click to expand...
Sounds just like what happens with our MSP's.
In our case it is the air density. The MAF will send a +2 volt signal to the ECU which shuts the car off for a split second and then it turns right back on.
In warm weather I never hit cut but as the temperature drops into the 30's I will hit cut at WOT. Hell with the quick spool I have and the high boost levels, I will hit cut at partial throttle as well.
I have a custom MAF that will be installed within a few days (hopefully.)
If I did not have the MAF then I would be installing a FCD to get around it.
Here is the MAF...
ry%3D400
 
I'm officially refutting the beliefe that these cars run quicker in colder weather. In theory they should, but I think with the stock ECU, they lose a good bit of HP in cold weather. My MS3 feels lively and ready to drive in any RPM range in 55+ F weather, but under that, I feel like I'm forcing the car to do anything, and on the highway at WOT, it just does not move as quickly.
 
The problem is the cold weather and the issue is fixed with a MAF clamp (Yes MAF and Not Map) which will clamp your MAF IAT at 80 Deg. There is a post somewhere from CPE about this. It's like a MAP clamp but sets your IAT reading at 80DEG and stops the cold air cut.

I will see if I can find the post. Every winter these same type of posts crop up and every year there are tons of stupid replies and answers with no knowledge or research put into it.
 
Bravnik said:
The problem is the cold weather and the issue is fixed with a MAF clamp (Yes MAF and Not Map) which will clamp your MAF IAT at 80 Deg. There is a post somewhere from CPE about this. It's like a MAP clamp but sets your IAT reading at 80DEG and stops the cold air cut.

I will see if I can find the post. Every winter these same type of posts crop up and every year there are tons of stupid replies and answers with no knowledge or research put into it.
Click to expand...

you know what, you are right, I remember reading a cp-e post about that a while ago, I didn't get any of this last year, but I guess since the flash and bpv things have changed. I'll go talk to Lou from cpe about the clamp.
 
Here is the link to the PDF that CP-E did for the Winter Cold Weather Fix. I believe you will get a CEL but not sure. They were suppose to be working on a solution for this but I think it got dropped because summer came. I hope this helps and everyone needs to pass on the word and let others know so we don't get any more guesses and people making off the wall comments about this car (though a lot may be true).

In searching for this link, it seems that Cobb is working on tuning out the fix with the AP as well. I don't have any cut myself, but I live in CA so the coldest I see is 30's and to be honest I don't feel the need to go WOT every chance I get.

http://www.cp-e.com/imgs/wfcf.pdf
 
Last edited:
tru-boost said:
The AP is a lost cause just as much as the car itself is! Look at all the mods you have and how weak your car dynoed. Hell my car with very similar mods on stock ecu dynoed at 300/340. People see more of this cutting when their car makes more power..... FACT! The reason most AP cars dont cut is because they dont make any power! I am convinced my car can beat any AP equiped car out there, fuel cut and all!
Click to expand...

Here is the deal. In addition to my post above about the cold weather fix, you need a tune. I don't care if its an AP or a SB, you need a tune. A MBC / Map Clamp (though I ran one for a bit) is a Hammer where you need a scalpel. I had all kinds of issues with running an MBC that had nothing to do with my mods but everything to do with not having any tune. My car ran pig rich and I bet your car still does even with your mods. I would guess you see 10's on the dyno.

You have already spent a lot of cash on your car. Go one step more and do it right and get a tune. AP or SB it does not matter which and I bet you will end up with a car with better LTFT's and AFR's which runs a lot smoother without issues.

Or you can do like me and trade it in next summer for the new Camaro (eekdance)
 
All the info above is a bunch of crap you never "need" a tune on this car. What just became avaiable from cp-e is a must have though. According to them they can now reflash your ecu to never fuel cut..... Ever! Needless to say i will be buying.
 
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