Jump to content
Ultimate Subaru Message Board

1987 gl won't idle lower then 1500rpms?


Recommended Posts

  • 2 weeks later...

You close the butterflies in the carb. That is where it would normally get air and how you control idle. When they are fully closed and you're still idling, you are getting the air from somewhere else. It's a vacuum leak. Probably a hose. Spray certain areas with carb cleaner until the idle fluctuates. Wherever it fluctuates after spraying is where your leak is.

Link to comment
Share on other sites

Any codes flashing on the ECU? Is the idle steady at high RPM or wandering/sputtering/cutting in and out? IAC is the first suspect on these engines, they get stuck...gotta keep them clean to work correctly. Vacuum leaks also as mentioned. MAF sensors also do very funky things to the injection rate on both SPFI or MPFI, and the old school Subaru MAF is not the best system out there for durability. You can try cleaning the hot wire but be very careful not to damage them. Aerosol cleaner from the big box auto parts store will work; for a while. If that resolves the issue be looking to buy a known good MAF cause the one you have in there now is on borrowed time. 

Link to comment
Share on other sites

Okay.....>We need to determine if this car is Carbed or SPFI.......

 

Being an 87 it could be either.........2wds and 4wd CALI spec cars will be SPFI,

 

49 state 4wds will be Carbed.

 

First thing to ckeck with either is the throttle cable....is it too tight???

 

If not....then again   Carb vs. SPFI could be different things.

 

Carbed:  IF it's not the linkage.....it's likely a vac leak......or an air bleed leak(slight difference)  the air bleeds are the slightly larger tubes that come from the top of the carb to the valve on the pass side of the intake........This valve is supposed to at idle nearly close the main secondary air bleeds, and to open the Primary Slow air bleed  (these are the ports that meter enrichment)........If those hoses, or the vavle are missing......or if the small "orifice" pellets have been taken out of the tubes......the car will pull too much air through the bleed.......causing a high, but lean idle.

 

SPFI:  IAC hose loose, weak, crakced, or the IAC stuck open.......check by pinching the IAC tube closed and if the idle drops that's the problem.  Idle can be adjusted using screw behind IAC passenger side of the TB

Edited by Gloyale
Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...