failed emissions - some DPFI questions (solved-bad cat)

jb2wheelsjb2wheels Wagonist
in Engine & Drivetrain
My 90 failed TX emissions for high HC at idle only.

Any tips?

I'm going to change plugs and O2 sensor.

How many coolant temp sensors does a DPFI have? Just the one under the distributor? Does this run both the temp gauge and the EFI? I wonder if the car thinks it's cold so it fattens up the idle mixture.

Car seems to run great except it seems to run rich and miss some at idle - I hear the occasional "spit" while idling.

Is there a Honda FI troubleshooting site somewhere? I'm curious about things like:
- when does EFI go to closed loop
- what sensors are used and when and how and located
- when does DPFI use one injector or both

I'll take any suggestions

Thanks for your help

emissions numbers were:

At 800 RPM (idle?):
HC 401 actual 220 limit (fail)
CO 0.43% actual 1.20% limit (pass)
CO2 13.1% actual no limit specified
O2 1.7% actual no limit specified
Dilution 13.53 actual >6.0 required (pass)

At 2700 RPM:
HC 89 actual 220 limit (pass)
CO 0.67% actual 1.20% limit (pass)
CO2 13.3% actual no limit specified
O2 1.1% actual no limit specified
Dilution 14.17 actual >6.0 required (pass)

Comments

  • Eagle BeagleEagle Beagle familEE
    Funny Part:
    Arrrgghh (running away) screaming to many standards and service limits
    tip 1: move to another state
    tip 2: change fuel to alcoholmix
    tip 3: bribe : )


    Serious, engine type series, milage etc ...
    'spit' as in misfire ?
    mileage as in valves ...
    ignition misfire due to fouled spark plugs or a bad plug. by burned exhaust valves (check compression),
    lean misfire (check for vacuum leaks, low fuel pressure or dirty injectors), rich fuel conditions
    (fuel saturated carburetor floats, excessive fuel pressure, leaky injectors or a dead O2 sensor),
    EGR valve stuck open, misadjusted carburetor idle mixture, misadjusted throttle body air/fuel mixture ... at this point
    the screaming started ...

    and dont forget : )
  • HxCforeverHxCforever Wagonist
    to many hydro carbons means you have to much air coming out your exhaust. check to see if theres no leaks in you exhaust, even a small whole will cuase you to fail. i know because i failed with a 160hc when legal limit was 120 here in milwaukee,wi. i took my car to a mechanic cause i failed to many times. well the test pipe and the whole drilled in the muffler by the previous owner was causeing my hc to be so high. fixed & passed.
  • jb2wheelsjb2wheels Wagonist
    Thanks for the tips, folks.

    Car has about 155000 miles. I adjusted the valves about 100 miles ago while chasing other issues that turned out to be timing belt off a couple of teeth. All valves were very loose. All in spec now.

    I also did a compression test and all cylinders were around 190 PSI. I was pleasantly surprised because it was overheating due to a stuck thermostat when I got it. I thought it would need a head gasket.

    The exhaust system is a mess from the rear suspension back, but I have not been under the rest of the car so I'll put it on some stands and check.

    The "spit" is a miss I believe - going after plugs today. No EGR on mine.

    I'll update any progress - thanks again - JB
  • wagodizzlewagodizzle Council Member and EDM expert
    you may wanna check your ignition timing as well, that could be a cause of the spitting/missing
  • SiWagonSiWagon Council Member
    Sounds like you have the cases.Now let's see what they mean:

    Running richcan cause ''some to LARGE amounts of HC''.
    Missing causes LARGE mounts of HC.Plugs is a good place to start.Also clean the Cap & Rotor.
    Find the cause of these probs.


    Retarding Timing will reduce HC.Maybe you're running too much adv.
    The other trick I use is to run up the front tyre pressure to 45PSI if TX is using the dyno smog test.This makes the engine work easier.Afterwards drop it back down.Also go drive on the highway to warm the CAT ,then leave your Wgn running @ the smog place to keep the CAT HOT.

    :) Good Luck.
  • jb2wheelsjb2wheels Wagonist
    Quick update = failed again after:
    - fixed radiator leak
    - Seafoam in oil
    - Seafoam in gas tank, burned through whole tank, now on fresh gas
    - Seafoam through intake
    - fresh plugs
    - fresh O2
    - oil & filter change

    drove for an hour+ and did not shut off before the test
    It actually failed worse...

    So I changed the plug wires and intake air temp sensor. The IAT was melted but still had good resistance readings. I did not get it retested yet.

    I was about ready to throw in the towel and take it to local Honda mechanic. Then I noticed the muffler rattles and is full of junk so I decided to pull the catalytic converter and see if it was dumping crap into the muffler - this is what I found...

    386.jpg
    387.jpg


    I'm no expert, but I'm pretty sure this is bad. I'll get a new one put on and get the muffler replaced (because it's full of crap and a true hack install) and retest. If it doesn't pass after that, it's got to go to a pro - nothing else for me to repalce...
  • Eagle BeagleEagle Beagle familEE
    owhman, that could be it (arggh... in the first place)

    its nice to get demotivated and such once a while ...

    but the winner never quits ...

    different points of view

    great story tho ... love drama me ...

    : )

    Catalytic converter (standard for some type)
    To stay effective, the converter must not be contaminated by leaded gasoline
    The converter can be overheated and damaged if its fed too much
    unburned fuel mixture form the engine
    - Dont push or tow the car to start, start with jumper cables
    - Dont switch off the engine while the engine is running above idle speed

    The last part is from the owners manual
    Personally i didnt know that ...
  • jb2wheelsjb2wheels Wagonist
    A final update because I hate reading "HELP" threads with no closure...

    My Magnaflow direct fit catalytic converter arrived yesterday (2 days early from Parts America). I put it on last night. I had to shorten the springs on the spring mounts and enlarge the spring mount holes on the new converter slightly with a file.

    Passed TX Smog inspection with flying colors. I think I'll take this converter off and save it for next year and put my, um, free flow stock converter back on.

    At 892 RPM (idle?):
    HC 10 actual 220 limit (pass)
    CO 0.00% actual 1.20% limit (pass)
    CO2 15.0% actual no limit specified
    O2 0.3% actual no limit specified
    Dilution 14.96 actual >6.0 required (pass)

    At 2622 RPM:
    HC 13 actual 220 limit (pass)
    CO 0.01% actual 1.20% limit (pass)
    CO2 14.8% actual no limit specified
    O2 0.3% actual no limit specified
    Dilution 14.81actual >6.0 required (pass)

    The numbers look to me like the converter is using the available oxygen to do the converting. It's VERY efficient.

    I also had the muffler replaced since it was full of junk from the old converter and the mounting was so bad the tip melted my bumper. :(
  • SweetOhSweetOh Wagonist
    Thats why i love colorado, as of now theres no emissions. I would fail and then some. There not mutch of the cad left i pulled it off and took a hammer to the cad and broke all the honeycome out. So basicly a open pipe all the way out. I was driving w/o a muffler for a while -(tell you what it sounded better the a fart cans that on about ever import i see)
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