Originally I posted this in Historic, but I got an update from my roommate. I had the wrong model year. The post belongs here instead.

 

My roommate owns a 1983 Subaru Brat. It has this problem in which it goes up a grade, it'll surge and stop, surge and stop, until the motor dies. My roommate has replaced the oxygen sensor, something that starts with an E, the fuel pump, the gas tubes, the vacuum something, and some other stuff but the problem is still occuring. What can anybody do? If you need more details, let me know.

 

I just spoke with him. He has done the following: All vacuum lines checked, replaced vacuum sensor, the EGR valve, and the fuel sensor, no problem with piston or rings, he had it tuned up a month ago, and he has already replaced the fuel filter. What else is there to check?

carb rebuild time imo. is ther a fuel pressure guage he could hook up to it and see whats going on when its acting up?

Already did that. No luck yet. Do you or anybody on here know anything about a pressurized fuel system on the Subaru Brat? He said to ask because the Chilton manual said something about it.

It IS tell-tale signs of a bad fuel filter.

I thought there were two fuel filters on the Sube - anyone confirm? r/ PK.

It IS tell-tale signs of a bad fuel filter.

I thought there were two fuel filters on the Sube - anyone confirm? r/ PK.

I believe he said there were 2 or 3.

there are usually 2 fuel filters....one in back by the fuel tank, and the obvious one under the hood

Already did that. No luck yet. Do you or anybody on here know anything about a pressurized fuel system on the Subaru Brat? He said to ask because the Chilton manual said something about it.

 

so he hooked up a guage already? did it read anything out of the ordinary when it was acting up?

Carbed EA81 fuel system is not pressureized. The pump output pressure is about 2 to 3 psi.

 

Sounds like his carb needs rebuilding to me. Or junk it and put a Weber or SPFI on it.

 

GD

Classic case of fuel starvation.Change the filters.

I took this page with everybody's responses home last night. He responded by telling me this stuff: According the Chilton's, the psi is 1.3 to 2.6 for the fuel. Also, he checked the idle speed, and EGI system. No fuel injectors, electronic distributor, distributor cap is lined up properly. can go from 1st to 2nd no problem, if on freeway going from 2nd to 3rd, it'll start jerking, first he thought it was ground wire, but it was okay. So was the oil pump. Sometimes it does it when going from 3rd to 4th on the freeway, can only go up to 45 mph while in 3rd. This model uses a thermal vacuum valve, this valve activates the EGR. The thermal valve checked out ok and so did the EGR. Check valve is okay as well. has a weber carb. According to Chilton's, the fuel system is pressurized. He replaced the fuel filters a month ago. He has checked the suction in the line from pump to filter. Float and fuel level in carburator checked out okay. He's next going to check the oxygen sensor below the boot.

Is this the Carter-weber one barrel or the weber 32/36. If its the later it doesnt use the O2 sensor so that should not be doing anything anymore.

I had fuel delivery problems when I got my brat(car hadn't been run in a couple of yrs.)Brat has Carter/Weber one barrel stock carb. Replaced the usual, all the filters, eventually the fuel pump quit. Could be crud in the tank, not able to unload enough as you get up to speed. The needle and seat in the carb float bowl could be sticking or the float level is wrong, engine starved for fuel at high speeds. When I was replacing my fuel filters, I used to hook up a rubber house into fuel line and BLOW BACK into the fuel tank(gas cap off/open) to see if it was crud blocking my fuel line. This did make a difference, and there is a way to drain tank(unscrew bolt) to see what is in the tank...This car used to buck and kick and it took awhile to get it running smooth...at one time I even though the ECU unit was bad...but it was all fuel related...good luck,rc