lilredwagon Posted March 21, 2018 Share Posted March 21, 2018 Thanks for trying to help,but I don't think that voltage is my problem. Optima battery and Maniac Motors hi- output alternator both less than 2 years old. Clean and tight battery terminals and all grounds,voltage meter in cabin for monitoring voltage,never less than 14.2V at idle,and doesn't drop/ fluctuate when my bucking occurs. I can drive for days on the street below 50 mph without any problems,idle is perfect. BUT once going on the highway at higher load,will do it exactly 10 min after starting. Zack K. Hmmm... I had a problem with one of my other cars that sounds similar. Only in that it happened at a similar time after a cold start. What it ended up being was during the switch from warm-up mode to the normal running map. This was on an Infiniti G37, so I'm not sure how much applies with the AVCS, but the VVTL system is a similar technology. But what would happen was the VVTL was either not as advanced in warm up mode, or it was fully advanced during warm up mode, but when it made the switch at 159* (coolant temp), the cam would advance AND it would give me full timing. So it was basically extremely advanced timing just for that instant. It wasn't an issue with the tables because the warm-up table and the normal running timing/VVTL maps are fine, it was just the transition crossing over the 160* mark. I don't remember how it was resolved, possibly with the VVTL motor, so for a Subaru that would be to monitor the operation of the AVCS motors to make sure they are behaving at that 10 minute mark when it throws codes. Between that and the voltage thing, those would be my two thoughts. Link to comment Share on other sites More sharing options...
Max Capacity Posted March 21, 2018 Share Posted March 21, 2018 I believe you use some fuel system cleaner, was it Berryman B12, I think that is the best stuff out there and was recommended on here years back. I just dumped a can, $3.17 at walmart, in on Monday, the car was running better 60 miles later. My wagon began to get a slight buck/hiccup under load once the boost began to build. I could feel it in a 3rd, 4th or 5th gear roll on, less then WOT. Today, I went to WOT in 5th from 65 mph and the car felt almost normal again. Much better then on Monday morning. Also, my car never throw a CEL so may be this wont help...but for $3.17... Have you been driving the car easy the past few months ? I put the full can when the tank had about 13 gallons in it. https://www.google.com/search?source=hp&ei=SluyWu-PBtXGjwPimZKoDg&q=berryman+b12&oq=Berryman+B12&gs_l=psy-ab.1.0.0l10.1767.4626.0.10209.12.10.0.2.2.0.165.1370.0j9.9.0....0...1c.1.64.psy-ab..1.11.1407...46j0i131k1j0i46k1j0i3k1j0i131i46k1j46i131k1.0.ApuCniW5og8 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
xt2005bonbon Posted March 21, 2018 Share Posted March 21, 2018 Bone stock stereo So why the HO alternator then? Link to comment Share on other sites More sharing options...
zactek Posted March 21, 2018 Author Share Posted March 21, 2018 I believe you use some fuel system cleaner, was it Berryman B12, I think that is the best stuff out there and was recommended on here years back. I just dumped a can, $3.17 at walmart, in on Monday, the car was running better 60 miles later. My wagon began to get a slight buck/hiccup under load once the boost began to build. I could feel it in a 3rd, 4th or 5th gear roll on, less then WOT. Today, I went to WOT in 5th from 65 mph and the car felt almost normal again. Much better then on Monday morning. Also, my car never throw a CEL so may be this wont help...but for $3.17... Have you been driving the car easy the past few months ? I put the full can when the tank had about 13 gallons in it. https://www.google.com/search?source=hp&ei=SluyWu-PBtXGjwPimZKoDg&q=berryman+b12&oq=Berryman+B12&gs_l=psy-ab.1.0.0l10.1767.4626.0.10209.12.10.0.2.2.0.165.1370.0j9.9.0....0...1c.1.64.psy-ab..1.11.1407...46j0i131k1j0i46k1j0i3k1j0i131i46k1j46i131k1.0.ApuCniW5og8 It was actually one of the first things I did when it started happening,and I've been using it for the last few years,good stuff, it's on the first few pages of this thread. I'm on my second tank after the cleanef. I have a decent balance of driving easy and letting her rip at max boost. I occasionally get her up to 110-125 late night on the highway. So why the HO alternator then? I was able to get it the same price as stock,so figured extra amps can't hurt and prolong the life of the alt. Zack K. Link to comment Share on other sites More sharing options...
zactek Posted March 25, 2018 Author Share Posted March 25, 2018 I've been letting the car warm up a little (at least to 130°) before driving and not pushing too much boost on the highway. For a week now,no bucking. Not sure what it means,but that's where I'm at right now. New FPR and lines with a fuel gauge in the works. Zack K. Link to comment Share on other sites More sharing options...
zactek Posted April 15, 2018 Author Share Posted April 15, 2018 I haven't driven the car in a few weeks,and haven't had time to diagnose anything. I got in today to occasionally start to keep the battery charge full,and within a minute got a CEL. Checked it,and got a P0335 Crank Position sensor malfunction. I changed this sensor last year (with a Delphi,not OEM) and haven't had any starting problems. Is this an anomaly or is this related to my problem? The car ran fine once I strarted it. Thanks,Zack K. Link to comment Share on other sites More sharing options...
ehsnils Posted April 18, 2018 Share Posted April 18, 2018 So why the HO alternator then? "Because Racecar" But you can have that also if you have other reasons - or that you just got your hands on one at a good opportunity. Link to comment Share on other sites More sharing options...
Mtman68 Posted April 21, 2018 Share Posted April 21, 2018 I have seen crank sensor issues across all makes and models of cars. Normally they like to quit once really warm and if you let the car cool down will start again. Why did you replace the crank sensor a year ago? Pretty much all 2 wire crank sensors are AC generating signals. Link to comment Share on other sites More sharing options...
zactek Posted April 22, 2018 Author Share Posted April 22, 2018 I have seen crank sensor issues across all makes and models of cars. Normally they like to quit once really warm and if you let the car cool down will start again. Why did you replace the crank sensor a year ago? Pretty much all 2 wire crank sensors are AC generating signals. I broke the sensor working on something else in the vicinity,damn plastic. Had it since last year. Waiting on a OEM one right now. My problem usually occurs when the car is cold or warming up,and then goes away (kinda,lol). My current plan is to change the sensor,then do the STI FPR mod,and then look into cleaning the injectors. Zack K. Link to comment Share on other sites More sharing options...
zactek Posted May 7, 2018 Author Share Posted May 7, 2018 Update: I finally replaced the crank position sensor with an OEM one,drove the car 5 times,and my misfire seems to have completely disappeared. Not sure if that was it; the only other variable that changed is that the temperature here has went from the 30's into the mid 60's,nothing else was touched on the car. My suspicion is that the aftermaket sensor was slowly going bad,and finally went. Hoping for the best,time with tell if that was it.... Thanks to everyone who contributed,Zack K. Link to comment Share on other sites More sharing options...
relative4 Posted May 7, 2018 Share Posted May 7, 2018 Thanks for posting the resolution. Link to comment Share on other sites More sharing options...
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