1st Gen R53 Cooper S Random Misfire - P0300

Discussion in '1st Generation: 2002–06 R50, R53 & 2004–08 R52' started by fishmonger, Jul 18, 2015.

  1. fishmonger

    fishmonger Well-Known Member

    May 13, 2015
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    #21 fishmonger, Jul 22, 2015
    Last edited: Jul 22, 2015
    that is not my car - just a photo I found online

    so it's this guy?

    [​IMG]

    connected here

    [​IMG]

    and here on the fuel pressure regulator?

    [​IMG]

    I'll pull the IC off tonight and have a closer look and maybe take some photos of what mine looks like. Above photos are not my car.
     
  2. fishmonger

    fishmonger Well-Known Member

    May 13, 2015
    984
    769
    93
    Madison, WI
    Ratings:
    +895 / 0 / -0
    small update - I have been driving the car on and off, short runs and last night even back out on the freeway, about the same distance it took to run into the misfire when it happened. A/C on, temperatures about the same, all ran just fine. Not a hint of misfire. I am slowly gaining confidence in this car again - which is important right now, because my Tundra sits in the garage without brakes while I am waiting for a box with new calipers to arrive...

    Obviously, I am all over the gauges, looking at boost, manifold pressure, etc - just don't know if the numbers I am seeing mean anything. In PSI, when cruising at 70mph on near level road, I have negative values around 3000rpm. Pulling up on a ramp, 4000-4500rpm, I see boost up to +3 psi. I have not done any full throttle 6k+ pulls, but I guess that is what I need to do to find out if there's a boost leak? Vacuum is certainly working fine - decelerating from the freeway I saw it down to -13psi or lower.

    Car going back on jack stands tonight to pull the lower engine mount Poly bushings. Driving me crazy how those rattle the car at idle. Also need to double check the rear of the car where I hear some strange noises when applying the brakes hard enough to rock the suspension. Just have to make sure the alignment guy tightened everything down. I don't trust "professionals" - I've found too many loose bolts after pros worked on my cars in the past.
     

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