Subaru seems to run better on 89 octane?

TurboFiat124

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Originally Posted By: Kira
You seem onto this problem or condition....you have a lot of data and observations swirling about. I've read that water in gas is a thing of the past with the ethanol. Ethanol carries the water away. I suppose gas stations can take advantage of the water attracting properties of ethanol and add water to gas but that seems like it could backfire. Could the higher octane fuel cause the engine to run in a "happier place", you ask? Sounds like it could to me. I always thought the 2.2l in my '95 Subaru was always straining. That engine had NO GUTS at all. No problem with that except that if it had no guts then why didn't it get higher mileage? It ran like a watch. After 138,000 miles (easily 3/4 open highway driving) it averaged 24.24mpg. Fairly low in my opinion.
When water comes in contact with alcohol, they attract but still the mixture still sinks to the bottom just like water does in pure gasoline. That was my understanding. That's what Sta-bil ethanol treatment is supposed to do. It's supposed to keep the water/alcohol suspended in the gasoline. Or so they say. I've wondered if regular Sta-bil even works. I just got through running out the gas in my spare lawnmower (a Troy Bilt) Saturday and it's been in there for 2 years and never been treated with anything!
 
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If you haven't already, use a can of Seafoam in the fuel - good maintenance habit whether you're having a problem or not, and will capture water. Through experiences with my '13 Cruze, '85 GMC, and sister's '84 Cherokee, the only thing I use regular fuel for is degreaser. It's just reflex now to push the 89 button at the pump, and my rigs thank me. Higher octane is particularly beneficial in weed eaters, etc., because the fuel is diluted with the oil mix lowering the octane, and they're a high-speed, high-heat engine that is more sensitive to energy content of the fuel.
 
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Originally Posted By: TurboFiat124
What tells the EGR valve to open? I know it's vacuum but is it just manifold vacuum? Or rather when does it open? Under deceleration? I could clean it like I did on my Explorer but if something is malfunctioning telling it to open and slam shut then looks like if I plug the vacuum hose off to it, it would remain closed. I could at least rule that out.
Ported vacuum eg just above idle it opens. You actually want it to work properly, the inert gas it lets through lets you run more timing. The only reason it closes is to give you decent vacuum at idle. If it hangs open you'll idle like a "cammed up" race car.
 

TurboFiat124

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Originally Posted By: Alex_V
Higher octane is particularly beneficial in weed eaters, etc., because the fuel is diluted with the oil mix lowering the octane, and they're a high-speed, high-heat engine that is more sensitive to energy content of the fuel.
Well that answers one of my unanswered questions. I've heard some people at work say their weed wackers were giving them issues and they tried running 93 and they ran better. ECHO 2 strokes say to run 93. I was thinking about trying it myself. My 2 cycle powered Trabant 601 has a C/R of 8:1. I may give it a shot and see what happens. The only vehicle I hope I NEVER have to buy 93 for is my 1998 Chevy Van 350 CI. That thing get's 9 MPG around town, 16 MPG around here and 17 MPG going to the beach (mostly flat land). I did try running Seafoam in my Trabant to see if it would remove any carbon buildup on top of the pistons. After a few tanks I removed one of the spark plugs and took a peep. I couldn't tell any difference.
 

TurboFiat124

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Originally Posted By: eljefino
Originally Posted By: TurboFiat124
What tells the EGR valve to open? I know it's vacuum but is it just manifold vacuum? Or rather when does it open? Under deceleration? I could clean it like I did on my Explorer but if something is malfunctioning telling it to open and slam shut then looks like if I plug the vacuum hose off to it, it would remain closed. I could at least rule that out.
Ported vacuum eg just above idle it opens. You actually want it to work properly, the inert gas it lets through lets you run more timing. The only reason it closes is to give you decent vacuum at idle. If it hangs open you'll idle like a "cammed up" race car.
I popped the hood and think I found the EGR valve (driver's side) but there is no vacuum hoses going to it! Just a wiring harness. Looks simply enough to remove, just two bolts and a threaded piece of tubing at the bottom (I think). I seem to recall the one of my 96 Explorer 5.0 liter was particular either hard to get to or required removing a bunch of stuff to get to it. Looked up some photos on Google and sure enough it's the EGR valve. I'll pull it and check to see if it's coked up.
 
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Ha! The only reason you need more than 89 in your van is if you up the compression several points. wink I've seen results with Seafoam that I never saw using the Gumout or STP brand additives that have a generously sized shelf devoted to them at Wal-Mart, but it's possible it wouldn't make a discernable difference for some people in some engines.
 
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Originally Posted By: TurboFiat124
I popped the hood and think I found the EGR valve (driver's side) but there is no vacuum hoses going to it! Just a wiring harness.
Well yeah there you go! The computer activates it at above idle, premise is the same as a vacuum one though there's tighter control. Fords are weird with DPFE sensors making EGR happen/ diagnose; I heard it explained as a patent dodge.
 

TurboFiat124

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Originally Posted By: eljefino
Originally Posted By: TurboFiat124
I popped the hood and think I found the EGR valve (driver's side) but there is no vacuum hoses going to it! Just a wiring harness.
Well yeah there you go! The computer activates it at above idle, premise is the same as a vacuum one though there's tighter control. Fords are weird with DPFE sensors making EGR happen/ diagnose; I heard it explained as a patent dodge.
Question is, how can I activate the valve to open when it's in my bead blast cabinet. My guess is there is a solenoid that opens the valve instead of vacuum and there what appears to be 6 pins going to to! Unless I take it apart and I'm afraid that might be opening up a can of worms. Unless just getting around the valve by cleaning out the inlet and outlet ports would do the job. That wouldn't clean the valve seat. That was the hang up on my Ford. A sensor was telling the ECU that the valve was not closing off all the way do to carbon buildup and kicking the check engine light on. I know your not supposed to be messing with pollution control devices but would there be any ill effects if I just made a gasket (out of high exhaust gasket material) with no inlet and outlet holes to just block the ports off? That way the thing won't coke up again if that is indeed the problem. This weekend I'm going to pull the valve off and look for some proper cleaner and clean the MAP sensor and the coolant temp sensor in the air cleaner box. I wonder if the oil from my K&N filter caused this problem. Seems like I read somewhere it can. The problem seemed to crop up not long after I installed it.
 
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I've cleaned saturn electric egr valves, the pintle is spring loaded and can be pushed in with a screwdriver. If it pushes hard, it means there's sticky carbon. There's also the "out hole" which is always free. I don't bead blast; I use carb cleaner.
 
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Your Baja's EGR system _should_ be totally computer-controlled. I suppose you could reprogram the ECU to never open the valve, but you'd have to alter ignition timing, too, to compensate (to avoid piston meltdown or other destruction). I don't recall how to get the EGR valve to hold open when off the car. NABISCO (okay, NASIOC) almost certainly has the tech info you need. Some of my fellow XT owners (that's the '80s-era wedge-shaped Subaru car, not the current trim level designation) used to soak their EGR valves in a solvent to get them freed up and functioning again. You could try some Lube Control (LC20) for that, but be cautious about the electrical portion of the thing. I also can't absolutely promise the plastic will withstand, though I believe it should.
 
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I had the same problem and wasn't dirty egr, but lazzy injectors. Try some ucl and see after kne tank if it gets better. If do, then you know your injectors coils are weaker by becoming with more impedance. Try to measure the resistance, if below 14 ohms, than may be clogged pindles. Try a ucl / cleaner, like those pea based. Techron made a difference in my scooby.
 
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