crazy ka problem

[Toshima]

Well I have not been driving the 93 240sx that much this month. But I took it to work to day about a 60 mile round trip. When I dron to work no problems at all, But on the way back home is another story. On my way home I hit traffic so im ideling for about 5 mins then I get through the light. But right before I go I notic that the car is over heating. So I try to get over but couldnt till about another 2 miles up the road. I turned on the heater and it helped alil it went down about 1 notch. So I park it and let it cool down then I cheack the fluid level. It needed water so I added some and it took 3/4 of a gallon to top it off. Then after that I started up the car and no more overheating but now it idels at 1800 RPM WTF? So what should I look at doing know. Im scard to drive it now because its ideling so high. When I stop its at 900 then about 3 sec later it starts to rise to 1800?

[Toshima]

anyone?

[ka24deColt]

i have no clue wat could be wrong with it. never really herd of that bfor.. my cars maf sensor was messed up and would idle up and down constantly but never overheated... so ya i duno but good luck on finding the problem.

[DjPantsSpecR]

my best GUESS is this:

you overheated the car, possibly due to the fact that you need a new waterpump and havent realized it yet.

but, even more likely, you've blown your intake manifold gasket due to the overheating, and a small leak is letting enough air to idle high. and thats a long shot.

[Florida240sx]

He's askign why the car is idling high... How hot did it get?? Did it peg out? Wondering if oyu warped your head... When coolant temp sensors go bad your idle goes high correct? Maybe the hot fluid killed the sensor??

[Toshima]

I dont think I need a new water pump because it hasnt overheated sence. It did "peg out" but when i turned on the heater it went down 1 mark. Ill check the intake manifold gasket. Also if the coolant temp sencor went out wouldnt it still over heat?

[DjPantsSpecR]

no coolant temp sensor wont cause any sort of these problems. you can overheat your coolant temp sensor everyday for at least 6 months without any damage.... unfortunately i know from experience.

either way, this is indeed a crazy problem. high idle problems almost only come from vac leaks. i cant explain exactly why it would just start happening all the sudden after an overheat.

i wouldnt be surprised if jsut one overheat on these KAs can blow the headgasket, but a blown headgasket or a cracked/warped head wont cause high idle conditions. again, i know from experience.

but, really the only thing i can come up with from an overheat is a potentially blown intake manifold gasket. however, every bad intake manifold problem i had not only caused a high idle, but it was a fluctuating idle that would rise and fall. other places i can think of that would cause this where coolant flows is the throttle body (another long shot).

i'll have to think about it more, but for now i would check out that intake manifold gasket

[fknfst40]

what i would do get a can of brake cleaner and spray it over the intake manifold and if you see the idle change then yea the intake manifold gasket is damaged if not then damn thats a crazy *** problem

[frapjap]

Check out ypur oil and see ig there is coolant in it (chocolate milks color and consistency.)

If so, it wouldn't be a bad idea to look at the head gasket.

[kimosogi]

Sounds like a vacum hose came loose but an blown intake manifold does make sense. For the mean time I would check the thermosate for the heating problem.

[Armstec_S13]

check the temp sensor on the intake manifold, mine did that, now it's fine check for corrosion (spelling lol)

[edgartheace]

Yeah check your temp sensor for proper operation. When your car is at proper operating temperature I think it should read 70-90 Kohm. If it reads any higher then your senso is bad and that could be causing your high idle.

[matt4pl]

a bad CTS making a car idle higher, possibly, but not that much higher. pressure test the cooling system, check the cylinder compression, do a CLT if you can. check for vacuum leaks.

[wherearemypants]

i know this is probably obvious, but when my car was idleing erratically, i used a volt meter and adjusted the tps... see how your car drops down to 900rpms before it revs up, i don't think this is your problem... i would check your IAC (Idle Air Control) and see if it's clogged... but the one that makes the most sense is the head gasket...