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Terrible Lack of Power, Bad IMRC and Intake Manifold Vacuum Leak?

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  • Terrible Lack of Power, Bad IMRC and Intake Manifold Vacuum Leak?

    Hey guys,

    My Contour hasn't been running that great lately; it lacks power. It happens in two stages, and I'm pretty sure I've figured out why. Now to fix it.

    When the car is cold the power is alright. The engine just doesnt have the usual power jump around 4000 RPM, it just stays flat. It's been like that for a few months. I was guessing the secondaries are not opening. Pulling DTCs shows the P1519 code for IMRC malfunction. So, I'm assuming I have to replace the module.

    When the car warms up and I do a couple of WOT pulls, the engine falls flat on its face and stays like that until I shut it off and let it cool. Right when it looses power, timing drops from mid 30s to 14 degrees when I'm at WOT above 5000 RPM. After that the car stays between 11 and 14 degrees of advance at WOT throughout the entire RPM range. Pretty crappy haha. I cannot accelerate passed 80 mph, and 0-60 times are 14+ seconds. The STFTs go 20% richer after this happens too.

    While trying to figure out why, I seem to have found a vacuum leak at the intake manifold. When I spray carb cleaner around where the upper and lower manifolds meet, the engine stutters and the RPMs drop.

    I'm guessing I need a new intake manifold gasket. I've already replaced this right after I got the car 6 years ago (and I've read its a common problem), is there anything that can be done to prevent it from failing again?

    Also, what about bad injector O-rings? They are in that area. Is that a common problem on these cars? Is there anything else I should be looking at?

    I have a 98 SE, so I'm planning on getting an SVT upper and lower manifold, TB and TB bracket, and a replacement IMRC if I am going in there. I know the SE and SVT injectors have different flow rates, but I'm guessing they are the same dimensions and have the same o-rings? Is that correct, or would I have to source 98 SE specific o-rings?

    Is there anything else I would need to swap over to the SVT parts?

    I've also put up a WTB post in the classifieds for the parts mentioned above.

    Thanks,
    Johnathan

  • #2
    After replacing the gaskets try these things:

    Try disconnecting the cable that controls the second set of throttle blades and wire them open.

    If that still doesn't help take the knock sensor out of the back of the engine and wire tie it up on the heater hose. Knock sensors are very sensitive, much like most woman, so disconnecting it will stop it from hearing voices that may not exist...
    Don Higgins
    Crew Chief Pro Drag Racing Software
    http://www.crewchiefpro.com
    1999 3.0 Turbo CSVT ** 2013 American Dragster with 1100 Horsepower 7.28 @ 185 mph

    Comment


    • #3
      After replacing the gaskets try these things:

      Try disconnecting the cable that controls the second set of throttle blades and wire them open.

      If that still doesn't help take the knock sensor out of the back of the engine and wire tie it up on the heater hose. Knock sensors are very sensitive, much like most woman, so disconnecting it will stop it from hearing voices that may not exist...
      Don Higgins
      Crew Chief Pro Drag Racing Software
      http://www.crewchiefpro.com
      1999 3.0 Turbo CSVT ** 2013 American Dragster with 1100 Horsepower 7.28 @ 185 mph

      Comment


      • #4
        You can get a new IMRC from Fordpartsgiant.com that is revised to not fail as often. I also would check live data too on ECT values and O2 sensor data. The engine temp should hover around 186 degrees when it is hot. If it is hotter than that check Catalyst function. When the cats fail. it runs around 200-212 degrees. In turn that overheats everything and causes backup in backpressure and overheats the motor.

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        • #5
          Funny you mention the loss of power when hot...experiencing the same type symptoms, and I know for a fact that my IMRC and intake manifold gaskets are in decent shape because I've just done em

          Comment


          • #6
            Just to add to the conversation. I had an issue where the IMRC wouldn't open at normal operating temps. To test I would pull over and open the hood, rev the engine to 4000 and see if the arm moves. If it moves, it's good. If it doesn't, there is a transistor that stops working when it gets too hot. Replaced it and that solved my issues. Of course, a new IMRC is easier.
            2004 Mint Chevy Z06 E85
            2004 F-250 Lariat 4x4 FX4 Off Road
            1998 CSVT 184 WHP/175 WTQ 233 WHP/215 WTQ w/Nitrous 75 shot
            2002 WRX E85 356 WHP 345 WTQ (RR self tuned) SOLD
            1988 RX-7 Turbo II (FC) Streetport 297 WHP/272 TQ SOLD.

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            • #7
              Originally posted by allstyle12 View Post
              Just to add to the conversation. I had an issue where the IMRC wouldn't open at normal operating temps. To test I would pull over and open the hood, rev the engine to 4000 and see if the arm moves. If it moves, it's good. If it doesn't, there is a transistor that stops working when it gets too hot. Replaced it and that solved my issues. Of course, a new IMRC is easier.
              Same exact issue, no IMRC function when at operating temperature and I can verify that the rod does move

              Comment


              • #8
                Thanks for all of the suggestions! It's been a while since I've posted, but I ended up changing a bunch of things and got it fixed. The issues were the gasket between the LIM and UIM (clearly flattened out and leaking on the front bank passenger side and middle cylinder) and dead IMRC module.

                What I did:
                - Installed SVT UIM and LIM
                - Installed SVT throttle body, bracket, throttle cable, and new TPS
                - Replaced all the gaskets
                - Installed a different IMRC module I got used along with the manifolds
                - Installed SVT injectors with new o-rings
                - Installed SVT ECU
                - Installed complete stock SVT intake

                The car runs and sounds much better now. It idles smoother, and the runners now clearly open around 4000 RPM. The SVT ECU pulls harder up close to red-line than the SE did, and the car revs much more easily now, it's great. I've noticed that it behaves differently with AC on than it did before.

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