Rough idle, doesn't want to start after fill up, runs rich, vacuum leak, backfires

[UnamusedPunk]

Hello all,

I've tried searching the forums for an answer, but I haven't seen one to all these problems.

My poor MS3 has been degrading these last 10k miles, I've got about 150k on her and i think her time could be done. About 15k miles ago I got a checkup done and the shop said everything looked great and that she was doing good on compression but the spark plugs needed changing. Ever since then things have just been going down hill..

Currently experiencing:

1) rough idle. When idling the car feels like its about to stall, then it pumps fuel back in, then it almost stalls, then pumps fuel back in. It's quite annoying. (replaced MAF but that didn't help

2) Doesn't like starting after fuel up. This is by far the weirdest. After you fill the car all the way up it has to crank for a few seconds and then you have to feather the gas pedal to get it to turn on. After you get her running, it doesn't have a problem starting again. She also has a hard time starting in really cold weather (freezing)

3) Running rich: car blows more than normal amounts of black smoke out when idling. I noticed this when i started to fill her up while the car was running.

4) Vacuum leak: I'm getting a generic vacuum leak code, can't find where it is

Any ideas?

[Marcus]

Did you ever replace the plugs/coil packs? Most of what you describe is AFR related and that includes the spark.

What kind of shop did you go to?

As for your vacuum leak, I found my fuel trims were off because both the TIP side and hot side IC hose at the turbo were loose. That was after the dealership was checking for a dye to see if my oil loss was at the turbo. I'd take a guess your leak is around the cold side intake manifold tubes or rear/hot side inter cooler hose.

[Marcus]

And was there a good reason to fill up the car while it was running?

[Marcus]

Also dont cheap out on regular pump gas. Your turbo needs better.

[flapjack]

Some things that may help:

1) When replacing the MAF sensor on these cars ONLY replace with a genuine OEM sensor. For some reason these cars never seem to run right without the OEM part.

2) It seems to me like your problem is a combination of a vacuum leak and some kind of EVAP system issue. Most likely your purge valve is clogged or stuck.

[rigor]

purge valve

[IvansMZR]

I'm having a similar problem with my MS6 but the idle dips between 500rpm-1500rpm..
Having a possibility of stalling while at a red light so i have to hold the gas up to 1200rpm in order for the guy not to stall out... On top of that, i quickly noticed a dramatic drop in power that the engine is supposed to give. No, i dont think it is a boost leak because i have checked all hoses and clamps for signs of looseness.. And i dont currently have an Accessport yet either. i have done some more of my own research about this kind of problem and i have either gotten the idea that it is possibly an EGR Valve or an Idle Control Valve as far as the idling is concerned but still havent got to finding out why most of my power is lost as well... Any Ideas? i'm desperate as much as the next guy so any advice would be very helpful..
Would you guys still say this is a purge valve Problem? if so, is there a way of cleaning it or should i buy a new one...?

[Carskick]

I'm surprised no one has asked yet, but OP, do you have an Access Point so you can give us data logs at idle or while driving? May help shed some light.

[MSMS3]

Find and fix the vacuum leak first. What is this "generic" code number?

[Marcus]

Originally Posted by IvansMZR I'm having a similar problem with my MS6 but the idle dips between 500rpm-1500rpm.. Having a possibility of stalling while at a red light so i have to hold the gas up to 1200rpm in order for the guy not to stall out... On top of that, i quickly noticed a dramatic drop in power that the engine is supposed to give. No, i dont think it is a boost leak because i have checked all hoses and clamps for signs of looseness.. And i dont currently have an Accessport yet either. i have done some more of my own research about this kind of problem and i have either gotten the idea that it is possibly an EGR Valve or an Idle Control Valve as far as the idling is concerned but still havent got to finding out why most of my power is lost as well... Any Ideas? i'm desperate as much as the next guy so any advice would be very helpful.. Would you guys still say this is a purge valve Problem? if so, is there a way of cleaning it or should i buy a new one...?

You can download an app for your phone and find a usb to ob2 dongle to connect the phone to the port.

How does it actually run? If you're idles that spread out, I'd check everything including the little vacuum tube from the IM to the the intake but its not the big recirc tube that goes into your turbo inlet pipe. I cant describe it right.

Since you say lack of power, I'll just say its your high pressure fuel pump. Probably and hopefully way off but you'll need to replace that eventually.

Whats your mileage at and mods, if any?

[IvansMZR]

The only mod on it is a MazdaSpeed Cold Air Intake, and mileage wise, it's at 99,500...
And what do you mean by IM Tube? I have just today bought a new Purge Valve for my MS6 and a buddy that works at a local Autoparts store has told me, his car idled the exact same way until he switched out his purge valve. He also owns an MZR but in an MS3.

[IvansMZR]

I also noticed...
When i start my MS6 on a cold start (If it doesnt die), it idles normally but stays on 900-1,000 Rpms up until i actually start driving it, the guy starts dipping on stop signs and Street lights.

[Carskick]

Originally Posted by IvansMZR The only mod on it is a MazdaSpeed Cold Air Intake, and mileage wise, it's at 99,500... And what do you mean by IM Tube? I have just today bought a new Purge Valve for my MS6 and a buddy that works at a local Autoparts store has told me, his car idled the exact same way until he switched out his purge valve. He also owns an MZR but in an MS3.

IM Tube probably means Intake Manifold.

Based on your description, I'd guess unmetered air is getting in, so I'd check for any leaks in your intake or TIP. Or your MAF is dirty.

[MSMS3]

Find that leak. If it is post-maf, you are sucking in unmetered air. That is also unfiltered air. Unfiltered air contains dust and particles that are abrasive and will quickly damage your engine.

[sho]

Having a hard time starting the car after filling gas is purge valve failure. Easy and cheap fix.