Ka24e idle issue, please help

[$avage]

My 1990 hatch has been giving me a idle issue lately and I was hoping I could get some help as to what it could be it would be very appreciated. I been reading other threads but the symptoms others have sound a bit different to what I have. The car just started doing this about two days ago and it's been having a bouncy idle only when parked or at a stop light and it bounces from 600 to 900 it does not drop under 5 or pass 1k. It doesn't feel like it's going to stall because it doesn't drop low enough and also I just noticed today that when I stepped on the gas driving and shifted at like 6k it went away when I threw it back in neutral. It went away doing this twice today and I'm not sure if that'll help find the reason for the bouncy idle. I'm still a newb working on cars but I would appreciate all the help I can get. I tried cleaning the maf yesterday with maf cleaner but it when I put it back on the idle was still the same.. Only thing that helps it is revving the car high when driving. I also get a smell of gas when starting and warming it up and I also backfire quite a bit, just thought I'd throw that info in. Thanks if you read and have a great day

[racepar1]

Well, check your fuel hoses. Check electrical connections at the TPS, MAF, and O2 sensor. Have you ever replaced the O2? Might be a good idea to do so. Check for vacuum leaks as well. How about your spark plugs, distributor cap/rotor, and plug wires? As for the idle, how does the throttlebody look? I bet it's dirty as hell, clean it. Also the idle valves mounted on the back of the intake plentum tend to get dirty/sticky and cause idle problems. Pull them off, pull them apart and clean the hell out of them with some carb cleaner. I'm willing to bet your problem is simply a lack of maintenance. Nobody seems to want to maintain their 240's. It takes time, costs a little money, and doesn't make the car any "cooler"...

[$avage]

Well I recently picked up this s13.. I'll definetly go through what you said. I appreciate your help. Not a experienced s chassis owner or mechanic of that sort but I've always had a love for them and want to learn as much as possible. Thanks again

[Snouki]

i have a similar problem. My car has the rough idle bounce from basically right above 0-1k rpm but only after its been running and driving for about 10 minutes(5/5). however the roughness does go away after about 10 minutes after I start driving. I think it could be throttle body/idle valves so ill clean them tomorrow but at the same time, I've idled the car for 15 minutes then revved it a bunch n let it idle again with no issues which leads me to believe it could be electrical.. also, my engine light came on today. evidently enough the cars been doing this since it came back from the shop for an egr cleaning and tune up to pass etest. I haven't taken it back bc of time issues + long weekend + i feel like this is something I can tackle.. with guidance lol ill try everything I can tomorrow n report back.

side note , I've been keeping the ac on at all times now. I can still hear it jumping, but the jumps are much smaller and bottom out at maybe 1k rpm. makes for less embarrassment bc my cars kinda loud lol

[racepar1]

Check your TPS and MAF sensor connectors.

[Snouki]

so my tps looks to be my issue. the way mine is set up, i have 2, 3 prong connections next to the throttle body. the lower of the 2 harnesses only has 2 wire going to it, when the top has all 3.

also, thought id mention this as well; my obd2 port wasn't working n found that a 7.5A fuse labelled "batt electron" (or something like that) was blown. swapped in a new one and pulled a p0133 code. 02 sensor circuit slow. could this have anything to do with the idle issue, or is this its own problem? sorry, not trying to hijack, just thought this was close enough to not make a new thread.

[racepar1]

Don't worry about the missing wire, it's supposed to be like that. One connector is for the closed throttle switch. On TPS's like that you adjust the TPS using the closed throttle switch. You want it set so that there is continuity when the throttle is completely closed, but no continuity as soon as it's opened. I doubt the O2 is your issue, but it certainly doesn't help.

[Snouki]

ok ill go look for continuity, thanks for your help

[Snouki]

hi, so when checking for continuity, i got mixed results. Im not 100% sure which wire to check to i checked them all. wire c(3) shows continuity, wire b(2) does not, wire a(1) does not. on the lower of the 2 harnesses i got continuity on wire c, but only a short beep once in a while. could this be it É on the top harness however when checking voltage on the middle wire, i got .48-4V range from completely closed to wop. is it possible im doing something wrong in my checks, or do i need to relpace the tps or lower harness

edit: opening and closing the throttle changed nothing for each wire. Im thinking I may need to adjust the tps but I have no clue where I do that. I dont see a closed throttle switch.

[Snouki]

update: i just drove the car after cleaning the throttle body and checking the tps and I'm slightly confused as to the results. The car drives waaay smoother, has noticeabley more power and even sounds better (not as gurgley, much quieter pressure pops). now the only issue is when the car first starts driving, whenever it idles the tach sits pretty low and sounds like it almost wants to die. after about 5 minutes on the road, the only issue is when the clutch is engaged, the tach drops to about 100-200 rpm and then semi-slowly climbs back up to 900 and sits there quietly. so i'm going to check a couple more sensors as well as the IACV which i suspect to be the culprit. if you guys have any other ideas, I'm happy to hear them!

[dukiespice]

Check the idle screw that's on the Iacv, that will adjust idle (ounter clockwise for more idle clockwise for less) take it out spray throttle cleaner in the hole/on the screw and put back in to your preferred idle. Had a similar issue with my car's idle too, and that's how I corrected it. As racepar1 said just a matter of maintenance s13s are a bit older so it's probably been a while . Also if not stated previously check pedal play/ cable

Good luck hope you can get the issue corrected

[Snouki]

Check the idle screw that's on the Iacv, that will adjust idle (ounter clockwise for more idle clockwise for less) take it out spray throttle cleaner in the hole/on the screw and put back in to your preferred idle. Had a similar issue with my car's idle too, and that's how I corrected it. As racepar1 said just a matter of maintenance s13s are a bit older so it's probably been a while . Also if not stated previously check pedal play/ cable

Good luck hope you can get the issue corrected

awesome, thanks for the tip! I myself have a 98 but it has been sitting for a while and hadn't passed test since 2009. so I knew coming into it it would be a lot of tinkering and cleaning, but thats what I wanted, something to keep me busy.