Crazy choking power loss after shifting under hard acceleration?

[turboge]

The ECU is self-learning and will adjust itself and fubar itself at random. It should be reset whenever any new problems occur. It will save the learned trim settings in a temporary cache, which is cleared when the ecu is reset.

The BPV does not cause the setting, its the MAF and the ECU. When you shift there is a RICH condition caused by loss of airflow which the stock ecu cannot correctly compensate for at all times. So when you release the throttle just enough for the BPV to vent some of that metered air.. what you get is an extreme rich because you are under load which is already injecting lots of fuel and then extra fuel goes into that which causes a rich miss and results in a jerking motion.

 

[Delivery_Guy]

The ECU is self-learning and will adjust itself and fubar itself at random. It should be reset whenever any new problems occur. It will save the learned trim settings in a temporary cache, which is cleared when the ecu is reset.

The BPV does not cause the setting, its the MAF and the ECU. When you shift there is a RICH condition caused by loss of airflow which the stock ecu cannot correctly compensate for at all times. So when you release the throttle just enough for the BPV to vent some of that metered air.. what you get is an extreme rich because you are under load which is already injecting lots of fuel and then extra fuel goes into that which causes a rich miss and results in a jerking motion.

So besides resetting the ECU, what is the solution? I'm guessing your Haltech can fix this, does Spool's E-manage? I think he said he is looking into this. Forgive me if I'm an idiot, only got 2 hours of sleep.

 

[turboge]

I know the haltech cures it, it still has a quick rich after blow-off but it does not interrupt anything because it's sensing off of MAP and not the MAF metered air.

The E-manage has a special function for this and it could be solved with a few tweaks on that particular map. I'll have more on that in a few weeks.

 

[BremertonMSP]

The ECU is self-learning and will adjust itself and fubar itself at random. It should be reset whenever any new problems occur. It will save the learned trim settings in a temporary cache, which is cleared when the ecu is reset.

I just don't buy that. Yes the PCM is self-learning as you call it. I think it's called Adaptive Strategies. But I don't think you should be resetting the PCM every time you think a new problem is occurring.

The BPV does not cause the setting, its the MAF and the ECU. When you shift there is a RICH condition caused by loss of airflow, which the stock ecu cannot correctly compensate for at all times. So when you release the throttle just enough for the BPV to vent some of that metered air.. what you get is an extreme rich because you are under load which is already injecting lots of fuel and then extra fuel goes into that which causes a rich miss and results in a jerking motion.

I'm not saying the BPV causes a rich condition. I'm saying the BPV may not be recirculating the incoming air quick enough, causing semi-pressured air to slam against the closed TB when lifting off the accelerator. This may be due to the fact that we are tapping into the BPV's signal line to control boost via our MBC.

I don't think it's a rich condition that's causing the bucking. I agree the PCM (ECU) controls AF ratios, but the MAF is not the only sensor used. You also have the O2 sensor, coolant temp sensor, Air Temp sensor, and Throttle Position Sensor (TPS). When you let your foot off the accelerator, the TPS instantly drops to a very low Vdc signal. This would immediately tell the PCM to go into Idle strategies. I would think if it was an overly rich condition, we would be getting some backfires when shifting.

Maybe we are just talking about two different things right now. I don't know. But I do agree that our cars still run too rich, period. Not flaming you turoge, you have good ideas I'm not entirely discounting.

 

[chwood]

for whatever reason the car seems totally fine today - I was just out driving at lunch and it pulled hard and fast just like it did before this little episode.
If this is simply a produce of fuel-rich on shift, shouldn't I have expected to have seen it before this? I don't run the track or anything, but I do push the car pretty hard driving around town just for kicks and it had never acted like this before.

 

[turboge]

I don't think it's a rich condition that's causing the bucking. I agree the PCM (ECU) controls AF ratios, but the MAF is not the only sensor used. You also have the O2 sensor, coolant temp sensor, Air Temp sensor, and Throttle Position Sensor (TPS). When you let your foot off the accelerator, the TPS instantly drops to a very low Vdc signal. This would immediately tell the PCM to go into Idle strategies. I would think if it was an overly rich condition, we would be getting some backfires when shifting.

My wideband o2 tells me differently. When I let off the throttle I've seen it go down to 10:1 instantly, this is from stoich to 10:1 then back to stoich in less than 1 second. What happens is when you partially pull the throttle the ECU is still injecting fuel for the airflow present at X throttle, X RPM, X TPS.... when you let the pedal off completely theres a quick dump of fuel coming through followed by NO fuel because the injectors are turned off until you reach 1200rpm, at that point "idle strategies" are turned on and the ecu resumes normal control again.

As far as backfiring, you will hear it if you get a larger free flowing exhaust, I had plenty of it with the stock ecu running the car. With the 2 cats, silencer and muffler you will not hear it backfire.

 

[Glowmunkey]

for whatever reason the car seems totally fine today - I was just out driving at lunch and it pulled hard and fast just like it did before this little episode.
If this is simply a produce of fuel-rich on shift, shouldn't I have expected to have seen it before this? I don't run the track or anything, but I do push the car pretty hard driving around town just for kicks and it had never acted like this before.

Mine does the same thing... sometimes I get it, sometimes it's fine...

 

[grandshervee]

ok so after reading all 5 pages, have I got this right? It has to do with the fuel richness and can be fixed with the ecu being flashed, yes/no?

Thanks

 

[CustomMSP]

Yes this has to do with the fuel richness, and no the issue hasn't been fixed with the flash. Atleast for me it hasn't.

 

[Prodigy926]

God these cars are a real problem for everyone. I have an 03 Mazdaspeed and I have had nothing but problems. My car also feels like it doesnt want to accelerate when on the highway and i always thought it was because of the draft from other cars or it being windy. Who the heck knows. Alls I know that there isnt a forum on here where I havnt had the problem. Everyone needs to start writing letters to corperate to get these things resolved.

 

[grandshervee]

maybe I should reconsider my purchase then as there seems to be a lot of problems with this car.

 

[CustomMSP]

what else are you considering?

 

[grandshervee]

a mazda 3. I really loved the msp, but I don't want a headache as my parent's 98 ml320 was one.

 

[CustomMSP]

I don't know much about the mazda3. What do you like about the MSP?

 

[Dr.Sound]

hmm, i guess there are lemons everywhere

i know of about 12 MSP owners, and only one of them had big problems.
problems like headunit messing up, sub blowing, coolant leaking....