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John, its a 92. I lost the pickup on my Small Car VSS and didn't know it. About that time I install a chip and thought my problem was cured. Almost two years later I discovered the missing pickup, installed the new VSS and had the problem again and realized it wasn't the chip that fixed it. This time when I disconnected the VSS I got the code. I runs fine without the VSS and the idle speed was stable, in park/neutral and correct in drive, but it bothered me that I was now getting a CEL and code 27. It was only when I ran without the VSS and then reconnected it while the engine was idleing that the CEL went away(instantly I might add) and it didn't start running bad, instead it ran like it did without the VSS. For this reason I believe the poor running, the CEL and code 27 and the VSS were related and relates to ECU learning and resetting. It may be that the ECU can learn to work with or without a VSS. Just how to cause that to happen I don't know, nor do I know if this would be the case with all SVX ECUs. I use premium, never tried the 87 octane feature of the chip. Thought I would point out the economics of premium vs. regular.

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- The sound you reference is high tension clicking? Coil voltage arcing to ground rather than firing the plug? Most easily heard while revving motor with stethoscope on plug coil?

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Right...Listen to the coil spark jumping to ground. Usually the coil has suffered heat and no longer sound. I always use manufactures coils on any vehicle needing them. Unless installing a MSD or Mallory system.

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Water spray bottle in the dark: Look for high tension leakage to ground when revving motor? (Like a bad set of plug wires on a foggy day?)

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Yes. listen for crackle of spark/s as rpm's increase .
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Always use OE subaru replacement coils? Do you typically replace all if one or two are failing?

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If the coil is obviously bleeding replace all, but if cracked, just the cracked coil.
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Disconnect O2 sensors. If stumbling improves, then bad coil(s) indicated? (as richer mix is easier to fire?)
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Fuel c/o% closer to 12 to 1 decrease the voltage required to push the spark across the gap. At idle, the voltage is around 12,000 to 14,000 volts but under load can require 20,000 volts and more.

As the engine rev's at 3000 rpm in N voltage can drop to 8,000 volts. If voltage remains high either lean or too big spark gap or wire resistance.

1000 to 1500 ohms per foot in plug wires if I use MSD Street wires.
R type plugs help fire the plug too. Most late EFI equipped engines require resistive plugs to reduce emi.

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92 SVX into 86 MT vanagon

I too get about 20-21mpg on highway only @ 55-60 mph
16-18 mpg whether have my foot in it or not around town

Derek

From: hisport <griffinjohnm@...>
To: subaruvanagon@...
Sent: Thursday, April 26, 2012 5:57 PM
Subject: [subaruvanagon] SVX MPG



Bob:

I have a couple of SVX correspondents reporting ~20mpg highway, but pretty sure this is at 55 - 60 mph steady. Seems doable, as my 17 mpg to date is av 70+ mph, with a van that ain't running right (yet)

IMHO, vanagon (esp westy) mileage is more a function of lousy aerodynamics than cylinder count. My clapped out 1.9L WBX didn't do any better than 17, albeit WFO most of the time.

--- In subaruvanagon@..., Robert Stevens <mtbiker62@...> wrote:

On Apr 26, 2012, at 7:45 AM, hisport wrote:

So far, i'm seeing ~17mpg mixed, which is sorta disappointing, but seems to be the common experience.

I don't have the SVX engine in my van, but your mileage report is on the high end of what i've seen other
SVX-powered Vanagon owners report here on this list. If I can ask … where did you get the information
that your mileage would be above what you are getting now, before you installed the SVX?

Bob

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You might try this : Run up the motor. Open the rear hatch and with a hose or stethoscope, listen around the coils as you pick up the rpm's.

Listen for a ticking...not the EVAP Valve. It is not uncommon for the coils to break down.( Most replacement coils read very low ohms, below the Subaru specs if you check the new ones..)

As the engine picks up under load, the ECU leans out the fueling to the point it becomes hard to fire off. If the coils are not up to snuff, they fail to spark the plug/s under these conditions.

Another way of checking coils is to spray them with water from a spay bottle....best done in the dark as then you'll see the spark/s.
Another check you can make is to disconnect the O2. This will cause the fueling to richen up slightly. test drive to check fro any change. reconnect O2 after test and clear code/s if set.

Remaining problem is low speed hesitation. Engine sorta stumbles upon part throttle low speed acceleration, especially up-shifting. May be worse when cold. Surges if allowed to fall to low speed in gear with no throttle (say rounding a neighborhood corner in third gear). Runs fine on the freeway. Makes smooth driving kinda tough.

Remaining problem is low speed hesitation. Engine sorta stumbles upon part throttle low speed acceleration, especially up-shifting. May be worse when cold. Surges if allowed to fall to low speed in gear with no throttle (say rounding a neighborhood corner in third gear). Runs fine on the freeway. Makes smooth driving kinda tough.

I hate to say it, and I'm not selling anything but you may want to get the chip, it pays for itself using 87 octane. I seem to remember drivibility improving when I popped it in.

I don't drive my van all that hard, it LOVES to be wound out a little. I am old school VW from way back, so it was hard for me to get used to driving higher RPMs, but this is not a VW motor, it bogs big time when loaded, especially on these SoCal hills and against the wind. Weight is not nearly as much a factor as wind. I towed a Kit car cross-country with a HEAVILY loaded van and it cheerfully tugged it, unless the wind was against us, then it bogged and mileage was practically cut in half.

I don't want to get into a discussion on tyres here.

I am also going to shy away from the mileage question here, I'd rather work toward a solution to your drivibility question, since that was the original post.

Neil

John, I have had similar issues with stumbling and hesitation with my SVX with Vanagon automatic. The wiring diagram shows a VSS input to the ECU but no specific information about how this input is used. Probably shift point input and low speed and idle response. My automatic runs great without the VSS but I get CEL with code 27 (OBD l). With a VSS hooked up the CEL goes away but it runs bad. This was consistent and it would run bad for weeks with the VSS. One day on my way home I pulled over and hooked up my Dan Flemming VSS, without turning off the motor. The light went out, and it has run great and the light stayed out. So suddenly it is happy with the VSS. This points to the adaptive nature of the ECU and when it may recalculate some parameters. If you are unable to pin point a more logical explanation for your issue, experiment with the VSS. By the way, here in California, premium is consistently 20 cents more the regular, representing a declining percentage of total cost for gas in the past few years. At $4.40 a gallon for premium you get to haul ass for .2588 cents per mile at 17 mpg. At 4.20 a gallon,not so much, and if you don't get 16.23 mpg you'r loosing money. John

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On Apr 26, 2012, at 7:45 AM, hisport wrote:

So far, i'm seeing ~17mpg mixed, which is sorta disappointing, but seems to be the common experience.

I don't have the SVX engine in my van, but your mileage report is on the high end of what i've seen other
SVX-powered Vanagon owners report here on this list. If I can ask … where did you get the information
that your mileage would be above what you are getting now, before you installed the SVX?

Bob

I just got mine running finally and am having similar issues with
hesitation (I think), though it doesn't seem to matter how fast I'm going.
If I mash the pedal, it runs great! Otherwise, it's a constant feeling of
stuckness/hesitation until it whips my head back and takes off with some
gas.

I'm glad I'm not alone in trying to figure this stuff out.