Hesitation and Leak Detection Pump

Discussion in 'General Discussion' started by OrlandoGT, Jun 11, 2021.

Car Parts
  1. OrlandoGT

    OrlandoGT New Member

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    Good Afternoon, I bought my 2006 RC in December 2018 from Andy (VPR PWRD), and it has been my daily driver, except for when it was at Powerhouse for a built engine, and other mods.

    Two weeks ago it started hesitating every time I start it up, and then it ran fine after a few minutes...even if I shut down and started back up right away. The hesitation was dangerous and was worse when I filled up until the few minutes passed.

    I replaced the Leak Detection Pump with an Autozone pump last weekend and it immediately fixed the problem. Now, a week later, it is starting back up again.

    My truck is NA with JMB cam and heads. I am concerned about the issue returning so quickly, but I suspect that replacing the LDP with a Mopar OEM unit may resolve this.

    I am reaching out to you all to take in your knowledge and see if there is something that I may be missing.

    Thank you in advance!
     
  2. rottenronnie

    rottenronnie Well-Known Member Supporting Member

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    Try this to reset the ECU:

    Remove both battery cables from the battery then touch the cables together for a couple of seconds.
    Reconnect the cables and start it up.
     
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  3. OrlandoGT

    OrlandoGT New Member

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    Ronnie, thank you for the tip sir. I will give that a try and post back with the results.
     
  4. rottenronnie

    rottenronnie Well-Known Member Supporting Member

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    You be welcome.

    It is worth a try.

    Changing a faulty component does not (often) nor immediately put the ECU back on track and it can take SEVERAL start/stop cycles to restore it's thought processes.

    It doesn't always take a faulty component to confuse the ECU.
    It IS a computer after all, and sometimes a reboot can work wonders.
    Disconnecting the battery cables is NOT a reboot; touching the cables together is, and will clear the RAM.

    I had a faulty TPS unit a number of years ago that was only reading 70% duty-cycle. Although I installed a new one, the ECU wasn't aware of it and the power levels remained dismal (70%).

    When I did the cable trick, it IMMEDIATELY returned to it's happy self.
     
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  5. OrlandoGT

    OrlandoGT New Member

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    Those are wise words indeed, and I appreciate your advice. I replaced the purge valve as well on the day I reset the ECU and my truck just drove better and felt faster with no issues. Hard to explain better than your explanation above. Now, about a week and a half later, it is coming back. Hesitation after startup is not as bad but the other symptom is still bad. When rolling in a parking lot after startup, the engine wants to die when I give it gas, so I have to feather it before it catches itself. So far I have replaced the LDP and purge solenoid. I had the fuel pump and injectors replaced about a year ago. I feel the solution is almost there. I’m thinking something vacuum related or the charcoal canister itself. The engine (NA cam) has been “gulping” at idle while I’ve been dealing with these issues. Your thoughts are appreciated.
     
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  6. rottenronnie

    rottenronnie Well-Known Member Supporting Member

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    Have you ever replaced the Idle Air Control on the side of the intake manifold near the throttle body??

    Your symptoms are "similar" to a failed valve with a stock cam but may change with a more aggressive cam profile like yours.
     
    Last edited: Jun 25, 2021
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  7. OrlandoGT

    OrlandoGT New Member

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    Ronnie, thank you Sir. I’ve been interested in the Idle Air Control from reading your posts over the years. It is definitely worth checking out for sure, and I will replace it. Sometimes our performance shops get backed up and I am thankful for helpful people like you. Happy Sunday.
     
  8. rottenronnie

    rottenronnie Well-Known Member Supporting Member

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    You are welcome.
    Yes, the Idle Air Control does a lot of work to help keep things stable.
    It is always a little tricky to diagnose by reading a few words.
    You will find the issue and your rig will be back in fighting trim in no time.
    Enjoy your weekend as well Sir!!
     
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