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Thread: New owner, just failed GA emissions, high NOx main culprit

  1. #26

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    Atlanta GA
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    1991 Dodge Ram 50
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    4G64
    Well, a new TPS, a new O2 sensor, and she still failed the re-test. NOx still the culprit. It is now passing on the 15 mph test, but barely failing at the high speed test. 1258 is the allowable limit of NOx, and the tailpipe sniffer said 1305. Before the work I've put into it was 4279, so I've come a long way.

    I've spent enough now to qualify for a waiver, but today I thought I'd mess with her a little more. I dug out my old school timing light, found the marks on the pulley and the front of the engine, and had a go at setting the timing.

    Hmm, even with the distributor cranked all the way to clockwise, it still is timed at about 11 degrees BTDC. Physically cannot be adjusted any closer to TDC. I seem to remember reading that if someone replaced the timing belt and used the deck of the head as the mark instead of the cast mark it made setting the ignition timing difficult. Think that's what I have here? Previous owner had the timing belt done 5K miles ago, but it was a friend of the family, not a Mitsu shop.

  2. #27

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    Maurertown, Virginia
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    How obNOxious to work so hard and be so close, yet not get the prize.

    Yes, the belt CAN be off one little tooth, but it seems to me you should be able to get in closer...do remember the stuff I learned about the ground wire to the ecu so that the timing is right. Let me find that post...

    Okay here it is http://www.mightyram50.net/vbulletin...spd-D-50/page6 and it was crucial information for me to understand, too. Once you do it, you'll always know, but before you do, it's frikkin' mystery.

    You can also take the time to remove the timing cover and check. My thread ("garage") has photos of the timing mark on the head, and if you highlight it on yours', you should be able to see it when looking through the radiator...unless you have A/C, in which case I'm clueless.

    EDIT: resolve posted here http://www.mightyram50.net/vbulletin...ll=1#post27020

    After connecting the jumper line, the timing checked out at past TDC! I adjusted it with the jumper in place, to just the left of the 5-dgree line. Removing the jumper, it registered 10 degrees before top dead center. Checked it again and it remained at 5 with the jumper on. So I know i got it.

    I lowered the idle to about 800 RPM: it had been a bit high.
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  3. #28

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    Actually I realized after my above post that I was calculating the 11 degrees on the wrong side of the "10" mark. In other words with, the distributor cranked over all the way clockwise, I'm at about 9 degrees BTDC. All of this is with the jumper wire in place. The jumper wire is an odd little step, I've never had another vehicle use such a thing, but I used it nonetheless. As soon as you ground that wire, the engine rpms change, so you know it's working.

  4. #29



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    If you can't get it to spec then most likely its off a tooth. Easy to do if not familiar with the engine.
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  5. #30

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    Quote Originally Posted by DroppedMitsu View Post
    If you can't get it to spec then most likely its off a tooth. Easy to do if not familiar with the engine.
    Yep,I pulled the top of the timing belt cover off and lined up the bottom pulley to TDC. The little dimple on the cam pulley is aligned with the head gasket, not with the correct mark one tooth lower.

    I Know the PO had it changed, but like I said earlier, it was a family friend, not a Mitsu specialist or realy even a certified shop. Looks like I'll be getting to know my engine a little better in a weekend or two.

  6. #31



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    Sacramento, CA
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    It looks like you found the problem. Yon just need to readjust your timing now.
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