Idle control screw screwed up my idling.
#1
Idle control screw screwed up my idling.
Out of the blue sky I turned 1/4 of the idle control screw attempting to raise the idle speed to 650 instead of 600. Now my idling is f. up keeping jumping up and down. I turned it back to original location, it did not help. If I did not touch it, I wouldn't have any problem doing 50 mile commute. Now I am afraid driving 5 miles without being stranded.
Mine is 1998 SE ~164M. Any wisdom, please share. I'll search old posts in the meantime.
Mine is 1998 SE ~164M. Any wisdom, please share. I'll search old posts in the meantime.
#3
I followed the same procedure as described in page EC-34. Turned the screw counter clockwise 1 full turn with TPS unplugged, raised RPM up to 1200 rpm while in park, didn't help. Unhook battery overnight to hope everything reset, it did not help. Cleaned TB, no change. Clean IACV, no change. Clean 6 spark plugs again (NGK Platinum 2647, the oem plugs, only 200 miles) no change. Spray brake fluid around for possible air leak, no sign of leak. Well, thinking bringing it in the shop. How does shop do tune up? What tool do they use? What else do they do? Educate me.Turning that screw out of the blue seems costly and puzzling.
TIA
TIA
#5
The engine had to be running to have this procedure working. The car should be on at all Times working on the iacv screw. Never adjust the screw with the car off the valve will get damaged in the iacv. The car must be on than the tps is disconnected to see the rpm fluctuate.
#6
there's no code.
I don't recall adjusting the screw while engine was not running. But will be careful to follow the advice. I notice that when TPS plug off, the idle was high but never stuttering.
Spent whole yesterday at JY pulling IACV and TPS to try it out. Also I watched couple videos, it looks harmless to adjust that screw. Will attempt to clean IACV and test it with a DVOM meter today. Someone said to reset IACV, repeat ignition key sequence "0, 1, 2, 1, 0" within 5 seconds for 20 times, assuming engine-start position is 3.
The engine had to be running to have this procedure working. The car should be on at all Times working on the iacv screw. Never adjust the screw with the car off the valve will get damaged in the iacv. The car must be on than the tps is disconnected to see the rpm fluctuate.
Spent whole yesterday at JY pulling IACV and TPS to try it out. Also I watched couple videos, it looks harmless to adjust that screw. Will attempt to clean IACV and test it with a DVOM meter today. Someone said to reset IACV, repeat ignition key sequence "0, 1, 2, 1, 0" within 5 seconds for 20 times, assuming engine-start position is 3.
#7
Solved. Thorough cleaning of IACV helped. What I should've done for the cleaning is open the 2 screws to access the plunger of the valve. What I did was I opened the beige plate that seals the electrical circuit. That part does not need cleaning. Car idles better now. No more rumbling, no more hiccups. My initial plan was trying to raise idling to +50 rpm more (CCW turns). Today, after cleaning, I ended up turning the screw CW several turns to slow it down to 650/700 RPM. From P/N to R/D, the idle did not drop much. That's a good sign.
Thank all!
Here is how it looks before. I did not take photo after.
Took me a while to clean these 'stubborn' residues. Brake cleaner, liquid wrench, metal pick, ....
Thank all!
Here is how it looks before. I did not take photo after.
Took me a while to clean these 'stubborn' residues. Brake cleaner, liquid wrench, metal pick, ....
Last edited by saig; 09-27-2020 at 05:15 PM.
#8
Nice work. Engine running should have no bearing while making adjustments. I didn't see that as a condition in the FSM. CLR is good stuff, check it out. Don't be afraid to bump idle to 750-800. Mine is set at 800 and with Nissan Datascan II I see between 725 and 800 while driving. Helps when at a stop to keep voltage up and smooth with no dips, keeps engine smooth when AC compressor kicks on, fans kick on, steering wheel is turned while at a stop, etc.
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