causes of erratic idling

[benchph1]

car: 1996 toyota corolla xl 1300 carb.

kotse ng friend ko to, pinaltan na namin ng OEM spark plugs,
top-dead center naman ang timing, ok naman ang hi-tension wires, tsaka nilinis namin yng carb gamit spray carb cleaner.

pero mapalag pa rin. pag idling lang naman pero pag nagaaccelerate na wala na.:confused:

[roydok]

Check the fuel and air filters at baka madumi na and needs replacement. ;)

[rodcarolino]

or engine supports

[jackaroo]

Is that the right timing per toyota manual? Check the specs, think it may be 5-8 deg Btdc.
Did you adjust the mixture via the air screw? Should be set at the highest idling point or before the idling roughens up.
Also, check your throttle stop screw, usually a long screw with a white knob.

[joreb0]

Originally posted by benchph1
car: 1996 toyota corolla xl 1300 carb.

kotse ng friend ko to, pinaltan na namin ng OEM spark plugs,
top-dead center naman ang timing, ok naman ang hi-tension wires, tsaka nilinis namin yng carb gamit spray carb cleaner.

pero mapalag pa rin. pag idling lang naman pero pag nagaaccelerate na wala na.:confused:

Bench,

Try spraying carb cleaner around the vacuum hose connections, pag lumala ang idle, you have vacuum leak. Rubber vacuum hoses tend to deteriorate with age. Look around for cracked ends. If the hose is long enough, you can cut off the cracked portion and re-insert.

[spazzkid]

OT: how do i use a carb cleaner? those are the ones that come in spray bottles right?

[joreb0]

Originally posted by spazzkid
OT: how do i use a carb cleaner? those are the ones that come in spray bottles right?

I'm talking about the ones that come in spray cans (aerosol). Be careful not to spray it on paint, it will leave a blemish.

[spazzkid]

so bubuksan ko ang carb then spray it on?

[joreb0]

Originally posted by spazzkid
so bubuksan ko ang carb then spray it on?

Yes, take off the air cleaner filter and you can spray it in there any where you can see gum and dirt buildup preferably while engine is running on idle. The engine will die so rev it up a little bit while spraying.:D :D :D

[spazzkid]

so i may need someone rev the engine to help me out with cleaning huh?

[joreb0]

Originally posted by spazzkid
so i may need someone rev the engine to help me out with cleaning huh?

No need, just turn the accelerator cable linkage on the side of the carb.:D :D

[benchph1]

Originally posted by joreb0
Bench,

Try spraying carb cleaner around the vacuum hose connections, pag lumala ang idle, you have vacuum leak. Rubber vacuum hoses tend to deteriorate with age. Look around for cracked ends. If the hose is long enough, you can cut off the cracked portion and re-insert.

we scrutinized each and every vacuum hose that is connected to the carb, and found 2 were cracked. we snipped the cracked ends and reinstalled it.....plus we changed the fuel filter.......voila!!! problem solved....thanks to all the peeps who posted their comments.:D :D

[chick-boy]

idling di ang problema ko sa 93xl ko. very noticeable ang drop ng idle kapag nag-on me ng park and headlights tapos sasabayan pa ng pag turn-on ng a/c compressor... what i did is increase the idling... kaso ang taas naman ng idle kapag walang electrical load. alternator na kaya o battery also has something to do with it? a couple of days ago lang ito nangyari...

[afrasay]

defective hose ng idle up switch or vacuum switch or the switch itself.

[benchph1]

This case is rare on EFI engines.....but what if i encounter it? what do i have to look for besides plugs, hi-tension wires, fuel filters & lines & also timing?

[redefine]

Based from toyota manual, rough idling may caused by Faulty spark plug, ignition wiring, ignition timing, ignition coil, igniter, distributor and high tension wires.