engine bogging down + misfire through in take
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This is a discussion on engine bogging down + misfire through in take within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; hello i hope this explanation helps .......... <<<<<<<<< i own a 95 wrx wagon with mods as discribed below td05 ...

  1. #1
    Registered User hillywrx's Avatar
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    engine bogging down + misfire through in take

    hello i hope this explanation helps ..........
    <<<<<<<<<
    i own a 95 wrx wagon with mods as discribed below
    td05 upgrade
    front mount intercooler
    headers and up pipe
    walbro f/pump
    bozzspeed ecu with 17 psi (dyno'd at 319 atfw a little lean at top end) 250 at the wheels.
    k+n cone filtter
    3in turbo back decated exhaust
    its some beast lol

    my problem is i have recently developed a misfire through the intake and a bogging down sound....almost like a long gasp of air before it will rev then miss then POP through the intake. driving is almost impossible as i need to build up the revs to about 3-4 k before it will move, coughing and popping. (i dont know if this is causing more damage driving it) the boost will build up, but as soon as it has then the above starts. its not at boost but low rev range onwards.worse under boost
    also i have noticed that when the maf is unplugged the car will start and rev normally (is this normal??) ive not tried to drive like this as i dont want to cause more damage to it.

    things have tried are
    removed turbo to my spare one (td04 but works fine) thinking it was that
    checked plugs and coilpacks (plugs are VERY SOOTY)
    checked for vac leaks (none seen)
    looked for loose plugs on loom
    ecu reset (z4 ecu remapped by bozzspeed japan)
    check fuel line pressure
    removed maf sensor and replaced with new one (well 2nd hand but working)
    compression test (figures at 160psi an 3 cyls and 155 on the other)

    i have run out of ideas and comming to the end of my wick with it....... if i had a bomb it would be all over the street where i live in bits lol. this is how im getting with it.

    can anybody help on this please or point me in the right direction of what to look for......?

    i know you guys an gals are quite clued up on things, lookin through this site...please help or i fear its gonna be one less wrx on the roads (hopfuly not)
    always expect the worst.........anything else then is a bonus.

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  3. #2
    Registered User teflon_jones's Avatar
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    Sounds like you know your way around a car pretty well since you checked all the right things. Why is it lean on the top end though if it's running rich the rest of the time (based on the sooty plugs)? Do you have an OBD reader so you can check for codes?
    Scott
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    Registered User hillywrx's Avatar
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    Quote Originally Posted by teflon_jones View Post
    Sounds like you know your way around a car pretty well since you checked all the right things. Why is it lean on the top end though if it's running rich the rest of the time (based on the sooty plugs)? Do you have an OBD reader so you can check for codes?
    hi mate thanks for quick reply...
    i dont happen to have a obd reader......although i thought that you can read these codes by the black wires under the dash?? by the blinking lights.no codes was found
    i found that it was rinning lean at top end on the dyno, the guy says it is just about safe takin into account that you never really get to top end in these beasts he suggested a walbro pump to compensate (maybe). the sooty plug thing has just happened since this problem started.... i have noticed my fule economy drop drasticly half a tank to do about 50mls (this is not right i was gettin good mpg considering the state of tune)...
    it started this problem about a week ago...no isusse with it till now.
    if you any ideas as to what to check please let me know its starting to do my bonce in.
    always expect the worst.........anything else then is a bonus.

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    Registered User hillywrx's Avatar
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    also could it possibly be the fule pressure regulator? causing it run rich hence the black sooty plugs.....

    has anybody ever had a problem with one, that can relate to the symtoms i am going through???

    hard to start from cold ( first turn of the day )
    hard to rev when started ( bogging down and will stall if you keep your foot on the loud pedal )
    sooty plugs
    poor fule ecconomy ( very poor )

    any help will be great ... thanks
    always expect the worst.........anything else then is a bonus.

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    Registered User Skreekin's Avatar
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    Do you have any tuners in your area? If it's possible, I'd get some readings while the car is running. Might be able to pinpoint where the problem is coming from.

    Can you post pics of the plugs?

    This is a difficult diagnosis since most of us are unfamiliar with the early of WRX. I would suggest that you hit up Nasioc.com and ask there.

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    Registered User hillywrx's Avatar
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    Quote Originally Posted by Skreekin View Post
    Do you have any tuners in your area? If it's possible, I'd get some readings while the car is running. Might be able to pinpoint where the problem is coming from.

    Can you post pics of the plugs?

    This is a difficult diagnosis since most of us are unfamiliar with the early of WRX. I would suggest that you hit up Nasioc.com and ask there.
    thanks
    i will try to upload some pic of the plugs. also try on nasioc
    always expect the worst.........anything else then is a bonus.

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    Good news, everyone! xxxxxxxAnub1s's Avatar
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    Sounds like a timing problem to me. I'd check your timing belt just to make sure. Being that your plugs are very sooty, I'd replace them just to rule that out.
    Cody
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    Registered User hillywrx's Avatar
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    Quote Originally Posted by Anub1s View Post
    Sounds like a timing problem to me. I'd check your timing belt just to make sure. Being that your plugs are very sooty, I'd replace them just to rule that out.
    thanks

    how can i go about checking the timing on a 95 wrx ??? ive heard these things can slip a tooth on the belt.... would this not cause a misfire code on the ecu? i am also gettin new plugs today to rule them out.......
    altough that said the car revs fine once the maf is unplugged with no miss.

    thanks again.....any pointers is great. ill look at the belt today to see whats what.
    always expect the worst.........anything else then is a bonus.

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    Good news, everyone! xxxxxxxAnub1s's Avatar
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    Quote Originally Posted by hillywrx View Post
    thanks

    how can i go about checking the timing on a 95 wrx ??? ive heard these things can slip a tooth on the belt.... would this not cause a misfire code on the ecu? i am also gettin new plugs today to rule them out.......
    altough that said the car revs fine once the maf is unplugged with no miss.

    thanks again.....any pointers is great. ill look at the belt today to see whats what.
    Guess I missed that part in the first post, if your MAF being unplugged has it running just fine, then I wouldn't bother checking the timing, although a belt inspection wouldn't hurt anything of course.

    Are you sure the MAF is installed correctly in the intake?
    Cody
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    Registered User hillywrx's Avatar
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    Quote Originally Posted by Anub1s View Post
    Guess I missed that part in the first post, if your MAF being unplugged has it running just fine, then I wouldn't bother checking the timing, although a belt inspection wouldn't hurt anything of course.

    Are you sure the MAF is installed correctly in the intake?
    i managed to get hold of a maf......ok only second hand and you can never tell for sure if 2nd hand parts even work when not on the car it come off.... hopfuly not bought a lemon off the guy. i suposse i could try to try to get one off a car that works and not sat on top off a pile of future pepsi cans...( scrapyard ) lol
    is it normal for the car to run without the maf even plugged in.

    thanks again
    always expect the worst.........anything else then is a bonus.

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    Good news, everyone! xxxxxxxAnub1s's Avatar
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    Quote Originally Posted by hillywrx View Post
    i managed to get hold of a maf......ok only second hand and you can never tell for sure if 2nd hand parts even work when not on the car it come off.... hopfuly not bought a lemon off the guy. i suposse i could try to try to get one off a car that works and not sat on top off a pile of future pepsi cans...( scrapyard ) lol
    is it normal for the car to run without the maf even plugged in.

    thanks again
    Yes it is actually. It has a MAP sensor as well that allows it to use limp mode fueling, at least on the newer WRX's, I'm not entirely sure about that generation since we never saw them here, but it will run, just not run as well. The MAF sensor gives the ECU the majority of the information needed to calculate fueling.
    Cody
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    Registered User hillywrx's Avatar
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    Quote Originally Posted by Anub1s View Post
    Yes it is actually. It has a MAP sensor as well that allows it to use limp mode fueling, at least on the newer WRX's, I'm not entirely sure about that generation since we never saw them here, but it will run, just not run as well. The MAF sensor gives the ECU the majority of the information needed to calculate fueling.
    thanks mate that makes sence.....

    i didnt know that v 1 +2 was not not in america.

    thanks again ill keep trying..... prosses of elimination i suposse.
    always expect the worst.........anything else then is a bonus.

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    Registered User hillywrx's Avatar
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    Quote Originally Posted by hillywrx View Post
    thanks mate that makes sence.....

    i didnt know that v 1 +2 was not not in america.

    thanks again ill keep trying..... prosses of elimination i suposse.
    ITS FIXED ha ha.......
    all the time i was taking things off and replacing sensors even the turbo, weeks of trying stuff.......
    last resort this morning was try the fuel pump. being new i did not assume that in first place........
    i found that the pipe off the pump that joins the fuel pipe to the engine in the tank had worked loose DAMN IT i must have been loosing pressure to the system tightend the pipe back as it should be and hey presto back to being her normal beast of her self

    thanks to all that have suggested things.......i am now a happy bunny again
    always expect the worst.........anything else then is a bonus.

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    Good to hear.

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    Good news, everyone! xxxxxxxAnub1s's Avatar
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    Glad you got it all fixed brotha.
    Cody
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