Engine Performance Electrical Problems EA-82

[logdog]

My Subaru is having many little electrical problems. For one, the idle is not completely kicking down. This is a non-turbo, 5-speed, 4-wd EA-82 w/ 210,000 mi. on it. It will kick down and then rev up, kick down, rev up, kick down, rev up repeatedly and quickly. Each cycle last about 2 seconds. Adjusting the minimum airflow doesn't affect the high-speed idle. The car will drop the idle to below 1000, like normal, if started after the car has been warmed and shut down. Once I drive off again, though, when I come to a rest, the idle cycles again. When starting from cold, the fast idle works normally.

 

Also, the lights rise and fall in brightness on my dash. The voltmeter reads at about 17 volts charging and I believe the brightness of the dash lights corresponds with this. I know it sounds like the regulator, but I'm not sure.

 

Also, the oil gauge doesn't work, never really has. We've had this car since it was puchased new in '89. Not the sender, we tried. But it does respond when the sender lead is grounded, as if there is high resistance in the gauge or wiring.

 

Many of the problem circuits appear to share some common circuits. I have looked through miles of wire on top of the motor, under the dash, etc. I got the wiring diagrams off of Alldata.

 

Help! please!

Thanks.

[daeron]

SPFI I assume..

 

Check the IAC (Idle Air Controller) mounted on the front of the throttle body. They can get gummed up over time, and that could cause your idle problem right there.

 

17 volts is too high; check the battery voltage with a multimeter while the car is on, and then check the battery for AC voltage when the car is on. AC voltage == bad rectifier diodes, replace alternator (or rebuild, if you're savvy)

 

The oil pressure sender is puzzling.. how sure are yuo that you swapped in a good sending unit? I'm not saying NOT to get a junkyard part for this.. but swapping in a junkyard part, only to still have the problem, does NOT mean that the problem is in the wiring, you dig?

 

What did you adjust on the idle flow?? the throttle drum set screw should not be played with; it is NOT an adjustment of any sort. To set the idle properly, make sure the timing is set dead on at 20* with the green plugs connected, and tweak the adjustment screw slowly. (I'm drawing a TOTAL blank on the actual adjuster screw right now.. I wanna say its on the driver's side of the TB but I truly cannot recall right now.) The big thing I wanted to tell you was that the screw that stops the throttle drum is NOT an adjustment; if you fiddled with it, it needs to go back to its original location before trying to set the idle.

[azsubaru]

I'm guessing that you mean the oil guage doesn't read at all. My oil guage had a problem similar to yours, and it turned out to be the meter, even though it would read when tested.

 

If you're pretty sure it's not the sender, about all you have is the wiring and the meter.

 

Pull the guage cluster out of the dash and disconnect the round plug behind the oil guage. The yellow/black wire on the plug (pin 3, I think) goes directly to the sender, so check the continuity from there to the other end of the wire at the sender. If it's good, then the meter is most likely bad.

 

The bouncing idle could be a misadjusted or defective idle switch on the TPS.

[logdog]

Thanks a lot, guys.

 

Yes, the car is SPFI and yes, the gauge has no reading whatsoever. The sender that I tried was a new one from the parts store. Someone else had also tried swapping it for a new one years ago, with no success. I believe the gauge is defective. Anyway, I'll have to look into the IAC again. I checked the continuity a while ago and it was within spec, but it deserves another check, as well as making sure the passages aren't gummed up. The screw that I'm talking about is on the front of the TB and the head faces the passenger side fender. I'll double check my timing. FYI, the check engine light comes on when the idle starts jumping around, setting the IAC code, as I remember. I'm going to look into it being gummed up, though.

 

What does replacing the diodes entail?

 

Thanks a million guys.

[daeron]

The screw that I'm talking about is on the front of the TB and the head faces the passenger side fender.

 

Sounds right, the screw I was warning about is on the passenger side of the TB, and i cant recall which way it faces, but it runs somewhat front to back of the car.

 

As for the diodes, I couldn't walk you through replacing them, most people just get a new or remanufactured alternator.

[Cougar]

I would recommend you just replace the alternator instead of fixing it. The time and money it takes to rebuild one as good as a remanufactured unit isn't worth it to me, plus if something goes wrong you have a warranty to fall back on with the rebuild.

 

I recommend you replace the alternator ASAP since 17 volts isn't a good thing to have going on the 12 volt system, especially for the headlights.