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FD Sputtering under heavy throttle

Old 07-14-17, 12:21 PM
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FD Sputtering under heavy throttle

My car seems to start and idle like normal. But recently, when engaging >30-40% throttle it seems like the fuel is cutting out when boost begins to build. I can baby the throttle up through RPMs, but as soon as its under load it falls flat on its face. Engine doesn't die, just limps back down with popping exhaust.

Nothing out of the ordinary before this. Just normal taking her out for a no-frills Friday commute to work, etc.

Is there maybe a secondary fuel injector fuse or relay I should be looking at? Clogged injector?

Thank you for any insight.
Old 07-14-17, 10:58 PM
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Does it blow black smoke when under load? Popping could be due to running super rich which is caused by either a large boost leak and unburnt fuel or maybe a faulty map sensor. Easiest thing to check first is whether the hose into the map sensor behind the intake plenum has split or come off.
Old 10-02-17, 08:37 PM
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Sorry for such late reply.

Doesn't look like any hose issues into map sensor. No black smoke that I notice.

Maybe unrelated, but clutch pedal has no pressure now either. Could it be related by vacuum assist or something?

Will probably be ordering new clutch slave cylinder and ss line from Pettit.
Old 04-23-18, 01:37 AM
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Still having issues. Checked vacuum lines as best as I could. Changed spark plugs, changed old gas, will be changing fuel filter next and then will try getting injectors cleaned.

If anyone has any ideas, I'd appreciate the feedback. Took some video. It's parked but acts identically under driving load.

Thanks.

https://youtu.be/J-CJ8LqiXr8
Old 05-10-18, 03:10 PM
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Originally Posted by LT 562
Still having issues. Checked vacuum lines as best as I could. Changed spark plugs, changed old gas, will be changing fuel filter next and then will try getting injectors cleaned.

If anyone has any ideas, I'd appreciate the feedback. Took some video. It's parked but acts identically under driving load.

Thanks.

https://youtu.be/J-CJ8LqiXr8
Mine is having a very similar issue. does yours idle ok?
Old 05-14-18, 03:45 AM
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test your coils resistance ? and send the injectors out for service. maybe try resting your ECU if your stock
Old 05-24-18, 02:40 PM
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ever figure this out sort have similar on shop FD car
Old 06-25-18, 11:13 PM
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Sorry for absence, life is just pulling me around.

Idles just fine. Haven't checked coil resistance, but installed new NGK wires when I did plugs.

I was able to pick up a PFC, as a few tuners who have been good enough to give me their thoughts (Neptune Speed / Garage Tuned) both are suggesting either bad injectors or injector driver or harness. So I'm going to try the PFC and hope it was the ecu and I come out with a tuneable setup after it all.

I've already removed the original ecu (bummer that it looks stock as seller stated it was Pettit) and should be able to install PFC sometime this week, hopefully tomorrow morning.

Thanks to all for input. Will update asap.

Last edited by LT 562; 06-25-18 at 11:15 PM.
Old 06-26-18, 11:48 PM
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The Apexi PFC fixed it!!! Looks like my factory ECU developed issues. Now I just need to go through and finish install (anyone have one of those brackets?), adjust idle (it's bouncing a bit), and setup/tune.

Thank you again to everyone for their support.


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