stu stu studder

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Tired of this. I've come to the realization that my wagon wil ALWAYs hesitate unless you all can give me more ideas on what to do.


First ill tell you what I have. 94 tw 22t/25d heads and manifold with jdm 440cc injectors. 05 wrx tmic and td04. Swapped 92 ss 5mt. Running a unnamed fcd. Walbro pump.

What have replaced as well. Tps( twice used and factory tuned them), maf (used), knock sensor (used), oxygen and coolant temp sensors new. Fuel filter new.

Now surging starts in th 2-4 k region when in mid throttle. If im easy on throttle I have nothing. Foot to the floor its not noticed ( this may have changed since I just finished the motor rebuild and have yet to break her in for a full on pull.

I have a lc-1 wideband in transit and also will have a pp6 within next week. Im hoping its just a fuel mixture issue as I have always smelled like im rich.


Please help or shoot me......

[BSOD2600]

Happen when engine cold and warm?
Got any vacuum leaks?
You sure that MAF is good?

[__TT__]

Warm and cold
Preaszure tested good
Not sure on the maf ( could be possible that I had two bad mats. How do I check it)

[Legacy777]

What are you using for engine management?

How did the injector seals look when you put them in? Did you happen to get the injectors flow tested/cleaned?

If you're running the stock turbo Legacy ECU with the 440's, IMO it's never going to fully control them properly and the way you want the engine to run. I don't care if people say the stock ECU can learn to run them. It may run better than when you first put them in, but it will not run properly. These ECU's already run rich, but sticking in 440's is only going to make the problem worse.

I would suggest starting with some wideband readings once you get it and before you put in the PP to see what is currently going on. Just out of curiousity, have you pulled the plugs to see how they look?

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Well keep in mind that this was a problem before the new motor and injectors....although the ecu may just be the actual cause I agree.. as for plugs they are brand new ngk iridiums

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Another thought is maybe its a ignited issue

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Wow. well i did a full ecu reset again (first time since the dohc swap) and let it run a full 15 min without any gas. and holy crap!!! smooth as silk this morning and POWA!!. I'll keep ya posted cause the studder has always been speratic (sp).

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Update


Got the wideband and the PP6 in. havent had time to tune or log afr readings yet but I have noticed this.

once the ecu resets its nice and smooth....but after awhile it progressivly gets worse untill I reset.