Questions About Hesitation And Injectors!!

[speedcicle]

First off I have a hesitation through boost, not all the time but at least 50% of the time. I have had the ecu flash done, but sometimes it feels like the car has no power. I have a boost gauge and the boost stays around 6 psi consistently even through the hesitation. Maybe it is a fuel problem? I also have a engine code for lean in bank 1. Which means the upstream o2 sensor is reading lean this is no good. Which leads me to my qusetion to what size injectors and fuel pump is in the car. If any of you have had this problem or have any info please let me know. Thanx.

[j12rock31]

whats up... well first off lean means one of two things, not enough fuel or to much unmetered air...... more then likely you have a vacuum leak, i would check that first...... Is you car under warranty?????

[speedcicle]

Yea the car is under warranty, but i don't trust the dealer, the seem not to know much about the msp's. And as far as a vaccuum leak my boost gauge is reading 20 in lbs at idle and the boost itself is solid at 6 psi throught the hesitation.

[j12rock31]

well listen..... there can be a vacuum leak causing your hesitation which you can not see on your boost gauge.... and as far as not trusting a dealer, this would still be your best option, ask around maybe you could find one somebody knows is good...... as far as the dealer not knowing about this car that depends on the tech i guess but the msp is not that much different from a regular old protege......... so i guess the tech would basically have to suck to not solve your problem.....

[speedcicle]

Need more input

[JDM Sam]

O2 sensor, cat or maf is fucked. ECU pulls timing and dumps fuel when in limp mode. What did you do to your car? Are you catless?

[jurgs01]

I would put money on a bad o2 sensor.Do you have any mods?

[speedcicle]

The only mod I have is a short ram CAI otherwise the car is stock. Haven't touched the exhaust or anything else. I am thinking that it is definitely a fuel problem, but what is confusing is that my tip on the exhaust gets some serious black build up in a short amount of time which would lead me to believe the car is running rich. But I do have the lean code so what I am thinking is that before the turbo spools i am running slightly on the rich side, but one the turbo spools i am leaning out in a hurry, so now I need to find out why this is happening.

[jersey_emt]

I have a similar situation, I occasionally get a P0171 CEL Bank 1 too lean. Boost/vac gauge does not show a vacuum leak. I've checked all the hoses, can't find a leak in any of them. Tailpipe gets black in a jiffy as well. But I don't have the hesitation at all. The car runs perfect in and out of boost. The CEL will come on for a day or two, then go off for a day or two, etc. etc.

[AlexTheBum]

im having a similar situation, when i get up to 4k. The car bogs like crazy then takes off, but it does it occasionally.

[jurgs01]

If you had an O2 sensor that was reading lean (when it really wasn't) maybe that would cause the problem. I don't know if you would get a different error code if one was reading good and the second bad. A vacuum leak would not cause you to run super lean (it would cause you to run more rich). If you are losing air that is already measured by the MAF the computer is going to give the amount of fuel according to the MAF reading (and other factors). Your MAF could also possibily be bad. I'm not a mazda tech though. There are a couple on here that might give you some advice (Blkzoomzoom, Binaryrotary). Shoot them a PM with your problem.

[JDM Sam]

see my above post.

[KyRaceFan]

Ive thrown that code before, but it was when i was at the track running 17psi. :eek:
I was on race gas and was having some "issues" fine tuning the boost that night.

[AlexTheBum]

17psi, that sounds like trouble.

[speedcicle]

Well I made an appointment with the dealer for thursday and i am gonna let them see whats going on. Hopefullly they will fix it, i am tired of this problem. So I will let you all know what happened, and maybe we can add a new problem to the list lol. Thanx for your help guys.

[MPNick]

The only mod I have is a short ram CAI otherwise the car is stock. Haven't touched the exhaust or anything else. I am thinking that it is definitely a fuel problem, but what is confusing is that my tip on the exhaust gets some serious black build up in a short amount of time which would lead me to believe the car is running rich. But I do have the lean code so what I am thinking is that before the turbo spools i am running slightly on the rich side, but one the turbo spools i am leaning out in a hurry, so now I need to find out why this is happening.
Where is your air temp sensor placed. It cannot be open under the hood.

[JDM Sam]

Where is your air temp sensor placed. It cannot be open under the hood.
It can but it will give you some crappy air temp readings and throw your timing around. Not enough where a check engine light should come on for just having an intake.

[wicked]

it's like this,I bet if you hook up a mt2500,or something and look at your long term fuel trim I bet you'll see it reading around 25,and your shortterm about 0.
they should both be at 0,but since it is running lean the computer is adding extra to make it right.
One thing,I promise you it's not a bad 02,and it's not from boost.also that it will only be lean in closed loop.

the reason you get the soot on the tail is because it ran lean for a short period,then the LT fuel trim compensated,so it is running normal,but the computer set the code because the LT fuel trim has to stay in this position instead of returning back to 0.
anything above 0 means the car was rich,and is adding fuel.
anything below is the opposite.

if you want to check for VAC leaks you should get a PROPANE torch,don't light it,and spray some light fumes around vac lines,and fittings.if you here the idel pic up anywhere it's cause you have a leak(excludeing intake pleanum)

02 sensors don't hardly ever go bad,unless something else caused it to.

"what I am thinking is that before the turbo spools i am running slightly on the rich side, but one the turbo spools i am leaning out in a hurry, so now I need to find out why this is happening."

no,actually the time you were running lean was actually at idle,onder boost you are insanly rich.

if you bring the car to mazda they can put it on a scantool like a mt2500,MOTIS,genasis,and they can show you what I am talking about in case I am not making sense to you.

[Mr. Win]

im going to take a guess and saay you have no idea what your doing and even if you dont trust the dealer hell prob have a better ides then you.

[JDM Sam]

O2 sensors go bad if too much fuel gets thrown or it gets subjected to too much heat.
Get the check engine light code read and post it back up.

P0171 is the 2nd o2 not sensing a cat. Your MIL isnt working.

[speedcicle]

im going to take a guess and saay you have no idea what your doing and even if you dont trust the dealer hell prob have a better ides then you.


I would have to say I have been a mechanic for 8 years and I know what I am talking about, it just that I am not sure mazda made the right upgrades for the turbo. I am going to send it to the dealer anyway because I only have a snap on scanner and I am pretty sure the techs at mazda have a better scanning tool than that. So hopefully they can read farther into tne system to find out what is wrong. As to where my air temp sensor is, i drilled a hole in the intake tube between the maf and the filter and put the rubber grommet in and the put the sensor back in.

[speedcicle]

O2 sensors go bad if too much fuel gets thrown or it gets subjected to too much heat.
Get the check engine light code read and post it back up.

P0171 is the 2nd o2 not sensing a cat. Your MIL isnt working.


PO171 is a bank one code that would mean upstream.

[JDM Sam]

I've had that code come up for running catless. Don't ask me. It should have been a code for something with the o2 circuit.

Either the o2 took a crap, or somehow when you put the intake filter on, you damaged the MAF. Put the stock air box back on and warranty it.

[JDM Sam]

Oh yea I just remembered something. You have stock i/c pipes? Check the hot side where the bypass valve connects. If that leaks you'll throw that code too.

[speedcicle]

I've had that code come up for running catless. Don't ask me. It should have been a code for something with the o2 circuit.

Either the o2 took a crap, or somehow when you put the intake filter on, you damaged the MAF. Put the stock air box back on and warranty it.


Thanx for your help, i am gonna put the stock airbox on before i bring it back, but this code has been there before i put the short ranm on. But who knows it could be a few different things, but i will let you know the exact problem once the dealer tells me, o yea and does anyone else's car almost stall when the fans shut off, when my secondary fan shuts of the car drops in rpm's down to like 300 and it has stalled once before at idle when this happened. I think i need a bigger alternator and battery combo because the headlights also blink when this happens. My guess is it is just to much draw on the electrical system.

[JDM Sam]

Ground wires like 1st MP3s kit will help that problem some. I know on nissans that if the coolant temp sensor is faulty it also causes a/f problems. Not 100% sure if it affects our system as much. But then again it would throw a code pertaining to the coolant temp sensor.

[wicked]

P0171 is the up stream,and when I ran into this problem I restset the FT,so as to check the actual 02 before correction.
the 02 was staying lean at about .09v,not switching at all.


is there any way one of you guys without this problem could reset your ECU,and check 02 v,and ST fuel trim?
check if your 02 is switching properly,and if your ST is staying at 0.

for some odd reason I feel mazda made a mistake.