Sudden power surge, EA81

[Frank B]

89 EA81 Hatchback 4-spd 4wd, all stock and kept in tune.

My comute is about 34 miles round trip every day. Half of that is up and over a small mountain. Open road, three lanes, smooth ride. But my little Sube can only pull it in third gear. I don't push the issue of getting up and over bt flooring it since it really doesn't matter to me, and it's only a little Sube, not a race car. Anyway, the procedure is, keep it in fourth untill it starts to struggle, downshift to third and apply half throttle, right where the linkage stiffens when it touches the secondary linkage, and no more. I will usually get to 55-60 mph when I get to the top, still in third gear. But lately I will only get 40-45 mph by the top and the engine isn't as smooth, not quite a miss. But sometimes as it's doing this, all of a sudden it will run smooth and a surge of power will accelerate the car up to 55-60 uphill! With no change in the throttle. I want to say it's the carb but it's a remanufactured(new) one and I'd hate to tear into it.

Has anyone been through this?

 

I'll try some fuel system cleaner and new fuel filters, it's due anyway.

[hatchsub]

Clogged fuel filters could cause a big part of that. Also, now that its cold out, our old carbed subarus will not run as nice as when it was warm out. Mine used to be getting 26-27mpg on the backroads. Im lucky if i get 23 now and the only thing that has changed is the weather. Cant say i have the same no power problem that u do but i do notice its a bit less willing to move as well.

[Sonicfrog]

Power Surge? EA81??? Never thought I'd ever see those two words in th same sentence!!!

[Frank B]

I never thought it would accelerate uphill like that either!!!!

 

 

I think it may be a vacuum/timing issue. I was replacing the oil pump today (what a treat!), and I found some vacuum leaks, or potential vacuum leaks anyway. I'll find out if that was it on my way to work tomorrow.

[LPGsuperchargedBrumby]

sounds like the vacuum secondary opening (assuming you have a hitachi carb) to me

[Frank B]

sounds like the vacuum secondary opening (assuming you have a hitachi carb) to me

 

I don't have the throttle open enough. It's hard to explain, think of driving a car with a noticeable miss and lack of power, then all of a sudden with no changes from the driver, it runs better.