idle problem that noone can figure out!!!

[wild_maxx]

ok i have asked this question once before a while ago but i figured i would ask again.

this is the weirdest thing that i have ever had a car do to me. i just bought an 89 240sx stock with the ka24e motor in it with only 90k miles on it:D but there seems to be an odd problem that i cant figure out or many others cant figure out as well.

when i start the car up cold it idles at 2k like it should for the warm-up cycle or something like that then i drive the car and let if heat up and go to park it and shut off the car, when i start it up again while still warm the idle will start at 1500 and go up to 2000 rpm's eveytime i start it and it will repeat this thing up and down about 10 times before it even starts to lower and i have to let the car sit for like 3 minutes before it is normal. i have no idea what could cause this and i hate driving it because every time i start it, it just revvs itself up like some stupid ricer would do outside of the walmart parking lot. i have no idea what could be causing this so any advice would help.

[12er]

check:throttle cableAACV body and hoseclean:AACVconfirm:AACV motor resistance (around 10 ohms)

cold idle doesn't normally go over 1500 (tolerable)..

where in WA are you?

[wild_maxx]

well i live in ocean shores washington. and i have cleaned just about everything i can think of. i ran seafoam through the break booster and throught the fuel tank to clean it all out but i still cant fix this problem. maybe some directions on how to clean what u metinoed already?

[12er]

sea foam through the brake booster?? why?

I'd suggest you measure the resistance of the AACV motor first before cleaning the valvebody, if there's some corrosion on the motor's connector, try cleaning it with either a very narrow file, or an x-acto knife...anyways..

cleaning the AACV is simple, but first get the replacement gasket(s) and some TB cleaner..

near firewall, on intake collector opposite side of TB, is the AACV (auxilary air control valve), you'll see a big air hose hooked up to it all the way from the intake pipe before the TB. Remove it with suitable tools, and clean the insides w/ TB cleaner. You may also want to clean out the inside of the IACV (idle air cut valve)body as well since it's in the same region.

Check hoses (intake, AACV, etc) for cracks or insecure mounting as well.

you live far away...like 3hrs from where i am..

[projeckDspdStar]

i've seen this idling prolem where it goes up and down because the O2 sensor was bad.. but i'm not sure about your case.

[ShifDown96240SE]

Im having a similar issue, I think the timing on mine needs to be adjusted, as well as some sensor replacements, and better iridium spark plugs. Mine is also running alot slower, and its noisy( ithink thats an exhaust leak) I posted mine in the New engine post

[wild_maxx]

12er i was told by a whole bunch of people to run seafoam through the booster line becuase it goes into the intake and cleans out all the carbon build-up and it did a good job. i have already done a complete tune up including new plugs, wires, rotor, cap, o2 sensor but i couldnt find the point that u use to check you timing. i looked around with the t iming light and didnt see anything. do u have to check it from under the car or what?

[Thee 240sx Owner]

its on the crank... if you look there should be a needle that comes out off the the top left of the crank.. and if you can rotate the crank and feel on the edges for a set of notches in the pulley... if they aren't shiny.. get a silver marker and mark all 5 or 6 of them and check timing.. the silver marks will make it easier for you too see it

[12er]

i see... thought you dumped seafoam into the brake booster..my bad.

base timing may be an issue as well, but i don't think it's the case..

[ShifDown96240SE]

what should the base timing be set at?

[12er]

for KA24E, 15 btdc +- 2 degrees..

[180fan]

Have you checked your coolant temp sensor yet? That could explain why you're going into fast idle mode every time regardless of your coolant's temp. I'd check that first.

[ShifDown96240SE]

If you look at my profile, I drive a DOHC not the E....

[12er]

ShiftDown96240SEsometimes us SOHC owners need also be reminded that DOHC types are out there...

lame joke aside, 91-93 DOHC are timed 20 BTDC. Not sure about the later S14 models, but should be the same I think.

[ShifDown96240SE]

thanks man, heh

[wild_maxx]

u all jacked my thread. j/k but can someone please tell me where the coolant temp sensor is located becuase i need to test it but i dont know where it is at. and also does anyone know the price for a replacement one that goes to the ecu beucase i disconnected the single black wire one and the temp gauge stopped working in the gauge.

[12er]

coolant temperature sensor on the E is at...... coolant return neck from head, intake side. it's somewhere down there.. next to the sender.. the sensor got 2 wires hooked to it (this reports to ECU). cost about $5-10 last if not mistaken remember (it's been a while)..

single black wire = temprature sender. no idea how much this is, but if the wire broke, you can always solder a new one in, if it broke at the connector... splice one in from junkyard.

[180fan]

Yeah I bought my coolant temp sensor at kragens for 16 bucks. The OEM one has a red plastic harness part. It's pretty close to the front of the motor you shouldn't have a hard time seeing it. The 2 wire is the one you need that part, the other one wire unit sends the coolant temp to your gauge.

[wild_maxx]

well i changed the coolant temp sensor and it didnt solve the problem. i dont know what is wrong so i will just take it to a nissan mech. does anyone know of any good shops around the tacoma or seattle area that is not too far away? i am in ocean shores if anyone knows where that is and there arent many good shops here.

[12er]

well i changed the coolant temp sensor and it didnt solve the problem. i dont know what is wrong so i will just take it to a nissan mech. does anyone know of any good shops around the tacoma or seattle area that is not too far away? i am in ocean shores if anyone knows where that is and there arent many good shops here.

PM me..

[Arrow]

I had almost the exact same problem w/ my '90... But this was after I cleaned my MAF, something in that caused my idle to be screwed up for a while (and it also completely messed up my tach readings aswell)

I would try to clean out you MAF, and also check you connectors. I had a high idle even after cleaning my sensor and checking them, I took off the MAF connector and found it to be completely corroded! Once I cleaned that my idle came a lot closer to normal!

Hope you solve your idling issues!