09 MS3 dies when warm

Discussion in 'Mazdaspeed 3 Troubleshooting' started by cavsfan2, Jul 29, 2024.

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  1. cavsfan2

    cavsfan2 Greenie Member

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    I have an 09 MS3 that acts like the fuel pump resistor is bad but it has been bypassed/deleted by previous owner. Here’s a mod list & maintenance list:
    Mods: (all done less than 100 miles ago)
    BNRS3
    Damond 3.5in intake
    3port EBCS
    FMIC w/ VTA BOV
    GGP VTCS delete kit
    Damond EGR delete
    Damond PCV plate w/ VTA OCC
    TurboXS catback/stock DP
    Overspeed Injector Seals
    Autotech HPFP internals
    Basemap tune by Farhan @ Damond

    Maintenance: (all done less than 100 miles ago except VVT-21k miles ago)
    Oil change w/ Rotella 5w40
    Motorcraft transmission fluid change w/ new fill & drain plugs
    Coolant flush
    Both front axle seals
    Injectors cleaned & tested
    New Circuit & Fuel Pump 2 relays
    OEM Pressue Relief Valve
    OEM Intake Manifold & Throttle Body gaskets
    Purge Valve
    Swapped back to OEM MAF from a Denso 604
    Boost leak test checked out good, blew 30psi through system
    3 Codes for EGR & VTCS deletes

    Car starts up fine on cold start but runs lean LTFT numbers at +20 but comes down as engine is warming up. 420-450psi HPFP at idle. 14.55-14.85 AFR at idle. Runs for around 11-12 minutes then just shuts off & wont start until cooled back down (3 hours or so)

    Did get a datalog (attached below) for the only logged drive I had after installing everything, 14 mile drive. (Had a previous 48 mile drive but forgot to log, a previous 14 mile drive where car died during drive the same way explained here) I was slowing down to come around a turn and when to throttle but had no response & car acted like I turned the key off and coasted to side of the road. Got a tow home. Overlooked everything, car started & mapped out a 14 mile route from my house & back & made sure to log this one. During the drive I had some throttle hiccups in 5th & 6th gears at light throttle, coasting at 55-60mph. Upon 14.1 miles car died again at 50mph & I coasted into my driveway. Farhan said the log looks like I have a vacuum leak (that I cannot find for the life of me). I’ve sprayed brake cleaner at all gasket points, boost leak tested, new purge valve & nothing has changed. All fuel pressures look fine until car reaches hot oil temps. I haven’t gotten the car to idle long enough to try & get another log nor a MAF CAL. Car has been a yard ornament for almost 2 months now due to me not figuring this out along with a couple other friends who are more automotive savvy than I am. Please send help lol
     

    Attached Files:

    cavsfan2, via an iPhone, Jul 29, 2024
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  2. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    What happens if you unplug the MAF?
     
    Easter Bunny, via a mobile device, Jul 29, 2024
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  3. cavsfan2

    cavsfan2 Greenie Member

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    When MAF is unplugged it would run much more rough then die out 5-10 seconds later. Never tried unplugging it when car was warmed up after initially dying out. A guy on the Facebook forums was saying his crankshaft sensor went bad but threw no codes & the same exact thing happened. He had oil caked in both male & female plugs and once it warmed up it would die out. My sensor also has oil all over it from a bad turbo oil feed line seal. I’ll have to try and set the crank at TDC, unplug & clean, and try it to see what happens
     
    cavsfan2, via an iPhone, Jul 29, 2024
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