View Full Version : almost unsolvable Idle issue

02-15-2012, 04:51 PM
I have a ka24de in my s13
when the car is cold and I start it up it idles at 1500rpm until it get to normal operating temp, so I figure that is okay.
But I can be driving aground and when I push on the clutch idles drop, and keep dropping until it bounces off the 500rpm mark for 30 seconds then kicks back up to 800.
some times it will even drop enough to stall out.
I used seafoam down the break booster, thinking it might be the IACV or something dirty, but that didnt do anything.
the check engine light blinks sometimes

when I was using an automatic ECU it would run fine, so I thought it was my ecu and sent it in to get inspected and a rom chip install.. my ECU came out fine but the problem persists :(

02-15-2012, 08:41 PM
Check for vac leaks

02-16-2012, 08:19 AM
Clean your maf and check to see if your o2 sensor is working right. See if you have any knock codes, knock maps will make the car run shitty.

Also see if your tps is set right.

I have made so many 240s run 100 times better just by checking them with datascan to see what all of the sensors are reading, cleaning/replacing the bad sensors or putting them back in proper adjustment or tq'ing the knock sensor properly.

Good luck

02-22-2012, 03:04 PM
it turns out it was the little sensor with one wire close to connected to the Intake manifold right next to the water temp sensor... :( the dumb thing wiggles and for some reason causes the car to act funny.

02-22-2012, 03:28 PM
Highly doubt thats the cause of your bad idling. That sensor just sends a temp signal to the cluster. The CTS is what the ECU reads for engine temps. GL!

02-22-2012, 03:46 PM
you would think so, I had been messing with stuff for a while and that's the only thing I touch and it make the idle go back to normal/ check engine light turns off..
I was thinking it was a messed up harness but all the voltages read good..

I could be way off, but you know what happens when you breath too much exhaust... :tardrim:

02-26-2012, 07:56 PM
have the same problem with my ka!!! do u any updates?

02-27-2012, 09:06 AM
Going to be honest.. the flickering ecu light I have is due to a bad circuit with the knock sensor.
I have no clue why the fact that if I jiggle it around it turns off the light and acts normal again , but I'm guessing I should probably replace the knock sensor before it throws off my timing map some more.
I'd suggest getting a consult cable for the computer to check the voltage of all the sensors.
I got mine for $15 from some chines company then got a $15 serial to usb cable off Newegg because I wanted my USB cable to be 3 feet long LOL

02-29-2012, 02:08 PM
If you can cause the problem to happen from that one sensor, then replace it. If the problem still exists, it could be along those wires. Cut and re-wire in some newer wires maybe.