Cold and Normal Operating Temps

[Nefarious21]

Here I am with another problem with my car haha

Ok so a while back I posted about my car not boosting and I fixed it with a non cracked exhaust manifold, but then I had another problem which was bogging like crazy (weak acceleration) and eating gas up like crazy, so I replaced the spark plugs with ngk's gapped to .032 and it ran like a beast until it warmed up. Then the bogging and misfiring came back again, but this time only when under boost. So I checked for vacuum leaks and found nothing, boost gauge reads from 20-25 inHG so vacuum seems fine either way.

http://www.mazdas247.com/forum/show...power-not-sure-please-help&highlight=hot+cold
I found this thread but no one ever figured anything out.
So I went out and did some testing, I noticed that when I hit around 5k rpm I would get a sudden surge of power so I decided to manually open up the valves on the passenger side of the intake manifold (don't remember what they are called) and hold them open with zip ties and BAM drives pretty darn normal! It still bogs a bit, but from all the reading I have been doing (over a week straight 4 hours a day) this is normal with this car. Non flashed ecu by the way.

My question is has anybody who has removed the valves or is running any other intake without them experienced bogging when warm? Also do you guys have any input on what is going on? Maybe the valves aren't opening when they are suppose to or one is stuck closed? Or should I be looking for something else and this was just a bandage to the problem?

No mods other than open down pipe (been to lazy to put everything back together), boost gauge, and a narrow band (I did not put this in the car haha)

Thanks guys, maybe we can help the guys from the other post too.

 

[CHIQLES]

this may not be right but i have been thinking it has something to do with how much pressure can be let go through the mani to get to the turbo. Manifolds are built to run in a certain rpm range maybe we exceed our range and cancel out the exhaust pulse from the engine and bog out.. I know there is the tuning side to much fuel not enough fuel but thats my thought. I know mazda has done some long runners for there skyactiv for that reason so they could advance timing and compression...since ive read an article about it, ithas stuck in my head..

 

[jdwk]

The "bogging" is normal. It is factor of a MAF based ECU designed for a NA car. As we all know, the car runs super rich straight from the factory.
This was to play it safe since there could not achieve very good accuracy with a MAF that is several feet of piping, an intercooler, and a turbo away from our manifold.

Since I owned an FIC I could actually see what the car was doing when it hesitated or bogged, and wrote up a long post about it. I think it all is still fairly accurate.
http://www.mazdas247.com/forum/showthread.php?123792646-Hesitation-explained-with-pictures

I believe what you are experiencing (and I have noticed this as well) is when the car is overly rich because it was adding fuel during the transition to open loop, the ECU is not able to anticipate the sudden change in air flow inside the manifold when the VICS butterfly opens. This leans out the mixture and you not only get the extra power from the increased airflow but a more powerful mixture as well, resulting in a very noticeable surge around 5k rpms.

Compare this to when the car hesitates below 4k rpms because it is too lean in closed loop and you get a surge of power as you enter open loop. At least in my car, when this happens I do not then feel the VICS surge at 5k.

When the engine is cooler, the intake charge is denser and I think the car is less likely to run rich and cause the 5k surge. I believe this is why you notice it more once the car warms up.

The MSP ECU is inadequate to properly run a turbocharged vehicle. Even the initial reviews of the car back in 2003 commented on the incredibly inconsistent power delivery.

Piggybacks can band-aid the problems, but they require constant tweaking, and the underlying problems never truly go away. My plan this winter is to get the car working with the ECU only handling gauges, fans, A/C, alt, and OBDII, and run the car completely with the megasquirt. If I am happy with the results, I will do a nice write up.

I know it is a long wait, but it is just too hot in Phoenix to do any significant work like this in the summer.

 

[tweety2300]

Hook an obd2 scanner to your car and see if your gettin p0660. This code wil not make your cel come on. If you get that code your Vic's solnoid is bad which is the flap you are referring to.