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Thread: Car shudders when letting off the gas after MAFT and sensor install

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    Car shudders when letting off the gas after MAFT and sensor install

    I posted this on the other site and think I have it narrowed down to what the problem is, I just don’t know what is causing the problem. Basically after installing the MAFT, my car will shudder right when I start to let off the gas. It does it probably 80-90% of the time. I found, watching the MAFT that the red LED (WOT) will quickly flash when letting off the gas. Watching my LCDBC and checking logs shows that the airflow Hz will spike up to almost 1900 Hz sometimes. It only happens when letting off the gas which makes me wonder if the MAF sensor needs clocked or if it’s a bad MAF sensor all together.

    Thoughts?
    1994 VR4
    MAFT, Z06 MAF, Cruise Control Relocation Mod
    BlackStealth LCDBC/MAC Solenoid/eBay GM 3 Bar MAP
    GZP Pre-set Cam Gears, Hotwired Pump and Bypassed Fuel Relay
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    M2 Turbo Back Exhaust, Gutted Rear Cat
    Clutch Reservoir Deleted, BlackStealth Datalogger
    Vacuum Reduction, EGR Delete, Resistor Mod
    HKS SSQV BOV Recirculating
    Tein S-Tech Lowering Springs
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    What bov setup are you running?

    Parting 6 speed
    Pampena 3.5 Stroker, GTX 2867 Gen IIs, AEM Series2, oohnoo SMIC, DN Hardpipes, FIC 1650s, Walbro 525, aermotive fpr, Dejon intake pipes, Tial Q, Koyo Rad, Samco Hoses, Stoptech 332mm fronts, HKS GT4 Coilovers, Spec 4+ LW, JDM 6 Speed, Billet shift forks, Pampena brace

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    Definitely BOV related.

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    SSQV recirculating. Kinda what I was thinking as well but the timing just seemed odd that it started exactly the same time as the MAFT install.

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    Are you running the air deflector inside the maf bubble?

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    Hmm, I don't know of an air deflector inside the bubble. I haven't removed anything. What does it look like?

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    Quote Originally Posted by Forest Gump View Post
    Are you running the air deflector inside the maf bubble?
    Just came across this thread on the other site: "Stock BOV Silecer/ Rubber Y pipe section in bubble definitive results." I might check into that when I get back tonight. This is what seems like is happening.

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    Quote Originally Posted by GrabberOrange View Post
    Just came across this thread on the other site: "Stock BOV Silecer/ Rubber Y pipe section in bubble definitive results." I might check into that when I get back tonight. This is what seems like is happening.
    Yeah, you might be getting some backwash into the sensor that is peaking it. I never had it happen, but I was running the deflector.

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    Well I verified it does have the insert in the bubble, fixed a couple vacuum plugs that were leaky, made sure all the fuel trims look good. I'm not really certain what the deal is. I figure this weekend I'll swap the stock MAF sensor back in for funsies and see if it does it with that. Outside of that the only thing I can think to do is a full vacuum test but it'll be a couple weeks before I can get to a garage that has a compressor with a regulator.

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    So I put the factory MAF sensor back in and it runs fine. Not sure what the issue world be. Sensor needs clocked, bad sensor, something else? Thoughts?
    Last edited by GrabberOrange; 12-12-2015 at 10:27 PM.

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