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Thread: Bogging down on acceleration and then leveling off between shifts

  1. #1
    Member sztybel's Avatar
    Join Date:  May 2011

    Location:  Flemington, NJ

    Posts:    39

    My VIN:    2647

    Bogging down on acceleration and then leveling off between shifts

    Good afternoon, folks,

    I have been doing extensive work on my car over the past several months. Primarily the fuel system. In any case I've cleaned out the entire fuel tank, replaced the fuel pump, fuel filter, oxygen sensor, catalytic converter and spark plugs.

    The car has been misbehaving when put under load. The best I can describe it is it bogs down when accelerating and then levels off. With each subsequent shift it bogs down and then levels off again.

    I haven't found too many threads about this particular problem. The one that did describe a problem close to mine mentions the frequency valve as being a culprit. I cleaned those contacts and will be giving it a drive again tomorrow.

    If anyone has additional suggestions I am all ears.

    Sent from my H1A1000 using Tapatalk

  2. #2
    Senior Member Bitsyncmaster's Avatar
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    Location:  Leonardtown, MD

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    Have you set your mixture via a dwell meter?

    Have you checked the ignition timing and that you get vacuum advance?
    Dave M vin 03572
    http://dm-eng.weebly.com/

  3. #3
    Senior Member
    Join Date:  May 2011

    Location:  Northern NJ

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    My VIN:    10757 1st place Concourse 1998

    Do you hear the frequency valve buzz? Checking timing, vacuum AND mechanical advance is also a good idea. Vacuum leaks can also be part of the problem As bitsyncmaster says, you should get a meter on the Lambda system and see what the duty cycle is. Does it "bog down" hot or cold or always?
    David Teitelbaum

  4. #4
    Member sztybel's Avatar
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    Quote Originally Posted by David T View Post
    Do you hear the frequency valve buzz? Checking timing, vacuum AND mechanical advance is also a good idea. Vacuum leaks can also be part of the problem As bitsyncmaster says, you should get a meter on the Lambda system and see what the duty cycle is. Does it "bog down" hot or cold or always?
    The bogging down seems to be consistent across the board whether the car is hot or cold. It will do it while revving but nowhere near as noticeable as compared to driving it.

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  5. #5
    Senior Member
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    Location:  Northern NJ

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    If it happens hot or cold then it isn't a CPR problem but most likely a mixture problem caused by either the frequency valve not working, a vacuum leak, or a need to tweak the mixture adjustment. You need to measure the duty cycle. If you don't get it fixed, there will be the Spring Social tech session this April in Parsippany NJ hosted by the DMA. Someone could look at it there for you.
    David Teitelbaum

  6. #6
    Member sztybel's Avatar
    Join Date:  May 2011

    Location:  Flemington, NJ

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    My VIN:    2647

    The latest update is I looked at the two areas where the banjo bolts connect to the WUR. The screen was pretty gummed up and I got that cleaned out. Car is running noticeably better, but still lacking power particularly when shifting gears. Once in gear I can slowly bring the RPMS up and get decent power.

  7. #7
    Member sztybel's Avatar
    Join Date:  May 2011

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    I just hooked up the dwell meter and it was reading right around 20 during idle. Then it dropped to 0. This was before the car reached operating temperature.

    Any ideas on what could be the issue based on this information?

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  8. #8
    Senior Member
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    Location:  Northern NJ

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    Did you hear the frequency valve buzzing? If the reading drops to zero either a connection to the meter came loose or you lost power to the Lambda ECU.
    David Teitelbaum

  9. #9
    Member sztybel's Avatar
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    Quote Originally Posted by David T View Post
    Did you hear the frequency valve buzzing? If the reading drops to zero either a connection to the meter came loose or you lost power to the Lambda ECU.
    I am going to check it again tomorrow. I was so focused on the dwell dropping to zero that I neglected to check if the frequency valve was still buzzing. It's possible that it did stop buzzing though because that connection is a bit loose.

    After I disconnected the dwell I took the car for a spin. Far less bogging down (I have a full tank of gas and added BG 44K Platinum to the fuel tank). I even have much more power going up hills. Not performing at 100% but far better than the pop and lurch experience from a couple weeks back.

  10. #10
    Member sztybel's Avatar
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    I ran the dwell meter last night. When the car first started up it was about midway on the meter and then dropped to zero within about 15 seconds. The weird part is I can still hear the frequency valve.

    It drove, with hesitation, both uphill and on straightaways. I feel like I am chasing a ghost.


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