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Rnning rich

Discussion in 'General Tech and Maintenance' started by itc007, Oct 4, 2005.

  1. itc007

    itc007 Junior Member

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    Happy October to all,

    I have a pretty much stock 1.5 in a 1991 civic, equiped with a header. I runn this in ITC thru the SCCA.
    I posted before on a stumbling problem I have with the car.
    I put the car on a mustang dyno at Wheel to Wheel in Michigan. Car starts up and idles real rich-9's and low 10's for A/F ratio. It runs in the high 10's and low 11's at WOT.
    Question is, how can I lean this car out with sock parts and or what would cause this car to run that rich?
    Thanks in advance to any info! [​IMG]

    Devin ( in need of help) [​IMG]
     
  2. VTECin5th

    VTECin5th Administrator

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    Alot of choices here as far as: bad sensor.
    o2 sensor maybe, misrouted vacuums, tune up?
    Fuel pressure regulator, dizzy problems, etc.
    You have any check engine lights on right now?
     
  3. itc007

    itc007 Junior Member

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    Brand new dizzy put in 2 months ago, changed out the fuel pressure regulater, new fuel pump a year ago along with filter. rebuild on the engine less than a year ago. new plugs, tried different wires. No check engine lights on.
    Things I have not done.

    Change the Throttle postion sensor or clean the fuel injectors.
    Thanks
    Devin.
     
  4. VTECin5th

    VTECin5th Administrator

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    I'm leaning away from either of those for some reason...
    Borrow someone's o2 sensor, and see if that helps.
    Mine was g0ne, but no CEL for it.
    I changed it, and got 5 more mpg, and reduced the black smoke on my rear bumper.
    Has it always done this, or just recently started?
     
  5. itc007

    itc007 Junior Member

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    O2 sensor has not been changed this year, so that is a possibility. It has done this sense the end of the last season.
    I changed the o2 sensor at the end of the season. Does the o2 sensor make a difference at WOT?
    Thanks

    Devin
     
  6. pissedoffsol

    pissedoffsol RETIRED

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    at idel, on a stock map, honda's idel in the 14 to 16:1 range when warm. although it sounds bad, this is perfectly normal. (cold starts have a little different thing going on, so i'm not even going to get into that.)

    if you're running rich on stock honda ecu, inejctors, and fuel pressure with no codes, it leads me to think something is clogged in the air flow path.

    less air is actually getting in than what was accounted for, so your burn process runs rich. it happens through out the entire rpm band...

    things to check:

    02 sensor (but technically this should throw a code if its REALLY in the 9's as its out of the narrow band's voltage range of accuracy)

    map sensor- check that the vacuum line isn't kiked, and that the port for the vac source isn't clogged or dirty.

    dirty or misfiring injector. your car is old. if the injectors are stock, one could be failing and staying open too long. could also be a problem with your resistor box/wiring or the actual ecu. but these should throw codes...

    check your timing. if your timing is off, everything is screwy. throw a light on there and make sure your base is around 16 degress advanced.

    clogged cat. if the air can't get out fast enough, it will back-up and do wiered things. i wouldn't say it would make you run rich, but it could be a factor in the problem.

    a very good posibility, is that the dyno's o2 meter is fucked up... but you do have a stumbling problem... so that's probably not the case.
    wide band o2's don't last forever, and esp. if they see race/leaded fuel, they don't last long at all. have the dyno guy clean the o2 with a propane torch next time you go in. or, have a buddy with a known good running car do a couple pulls to validate the o2 (or just watch another customer's results)


    all in all, i'd start with a simple can of injector cleaner in a tank a gas. run that through... see if it does anything. if not, $5 gone.. oh darn.

    if that doesn't help, throw the imting light on it.. check your distributor marks, make sure you're at about 16* advanced at idel. if your idel is off or bouncing, it will be hard to get an accurate reading.

    do a leak-down test. you might have a faulty valve or ring or something leaking in some crap and screwing up the mixture.

    bleed your coolant system. you'd be suprised what an air pocket can do... coolant temp sensors can also be mis-leading. throw an ohm meter on that and get out your manual to see if its in the service limits.

    check the tps. throw the ohm meter on it, and with a buddy in the car test it with key on, engine off, closed to wot voltage ranges. make sure its in the 0-5v spec.

    drop the cat back at the cat, grabd a flash light and inspect the honey comb on the cat. if it apepars intact and not clogged, should be ok.


    those are the free things i can think of...

    try some of those out and let us know
     
  7. itc007

    itc007 Junior Member

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    Wow!!

    That was great!!
    Thank you for taking the time to give me all that info.
    [​IMG] [​IMG] [​IMG]
    I really do appreciate all that info, alot of stuff that I would never have thought of.
    I will try that stuff and get back to you.
    Thanks again,
    Devin
     
  8. VTECin5th

    VTECin5th Administrator

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    I suggest Prestone injector cleaner (flame all you want until you try it)
    It's in an almost yellow almost orange bottle.
    They have a yellow and an orange bottle, so you gotta find the color in between those.
    It did help out alot on my single cam.
    I think i had a squirrel stuck in one of my injectors or something, and it cleaned em right up.
    Also hear good things about Lucas products.. never used any, I can't opinionize.
     
  9. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    good stuff that prestone injector cleaner...fixed a friend of mine's injectors...but i still have the same problem...might not be my injectors though.
     
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