extremely high idle

[bonestock240sx]

Alright heres the deal. Im new to the 240sx and yeah your thinking retard go ask the question. ALREADY DID THAT. No question matches mine or is even similar. So i have a 1991 Nissan 240sx. Its in fabulous condition. but i decided to spray some intake cleaner that cleans valves and stuff. right after i did that i have had a very irratic idle. its goes from 1500 to 2000 back and forth and sometimes it idles at 22-2300. i cant get it to come down. after the intake cleaner incident i got a CAI. that didnt change anything. i used MAF cleaner that helped nothing. So what next? any ideas also side note.... sometimes it will idle at like 1300 but once i touch the pedle its back to 2000, as well as when im driving and i push in the clutch it will drop down to a normal idle for liek 5 seconds but pop back up to 2000. im totally confused let me know what you think is the problem. and no need to flame because i already did my research all over the internet as well as on many 240 forums. o and the type of intake cleaner i used was AMSOIL Carburator, Intake, Valve cleaner. Thanks

[jetroy240]

many possibilities for high idle, a vacuum leak(hoses or intake gaskets), tps problem (check for codes), ISC inop., injectors leaking, throttle plate sticking (full of carbon deposits), etc. What's a CAI? Check ur distributor probably soaked w/ oil.

[bonestock240sx]

well i dont know how it could be any of those things because before all of that it was perfectly fine. nothing was wrong with it. all i did was open up the air box and removed the filter and sprayed throw my intake. and CAI is cold air intake.

[jetroy240]

try to swap a known good airflowmeter, u will confirm this if u got an afm code. Spraying could have damage the afm.

[blacksrjdm]

Wait so you sprayed intake cleaner through the maf????

If so, buy a new maf and dont do that again. Intake cleaner is meant to be added after the maf like right into the throttle body. Or most intake cleaners are to be added through a vaccum line with a special tool. But you dont wanna spray that through the maf.

[bonestock240sx]

i thought the MAF was to the right of the actual intake hole like the little oval hole with the hot wires to the right. but i guess its a possibility that i actually got some sucked up in there. thanks! for the help

[blacksrjdm]

If you pulled the aur box apart and sprayed it through the intake from there, then you sprayed right throught the maf.

[bonestock240sx]

ight thats what i did. should MAF cleaner work though. or do you think its screwed and probably have to get a new one. i have ran some maf cleaner with some luck but it just went back to high idle

[romerider153]

this happened to me it turned out to be once i cleaned out the TB the blade didn't seal all i had to do was adjust the stop on the TB and it idle perfect again

[romerider153]

didnt read that u sprayed it in the MAF tho yea u probably screwed the maf up

[bonestock240sx]

so i have tried 3 different MAF and nothing changed so whats next. my ECU flashed a code 12 which is MAF sensor and circutry. so idk what to do next. what else do i check.

[240sxmech]

unplug the maf and start the car if your idle comes down then its your maf.. The maf sensors that you tried were they new or used from like a junkyard? Also for the guy who posted the possible problems earlier if you have a leaking injector you wont have a high idle you will have a lower unstable idle because it will be running rich not lean. Lean is what causes a high idle, that is why if you have a loose vacuum line or a leaking intake gasket it idles high because it is sucking air after the maf sensor and is not being registered for fuel control....let ne know what you find good luck

[240sxmech]

You could have also dislogded some gunk and it made its way back to your IAC motor..The worst thing to do is clean your maf sensor and then start the car with out blowing out the cleaner because it will cause the hot wire to short out and ruin the maf. You can spray carb cleaner or maf cleaner on them but just blow it out before you put it back on or plug it in and try starting the car.. Hope this info was helpfull to you

[bonestock240sx]

i have already disconnected the MAF and started the car it stayed high. i also used some used ones. but they come directly off the a running 240sx that used them. and that didnt change anything. the MAF cleaner didnt really do much. but i dont know where there would be a leaking hose because it wasn't doing this until after i sprayed the cleaner through. so it definently cant be that. the ECU read a code 12 which is the MAF. people seem to not be reading this part.

[1KleenS13]

I would try and reset the ecu by disconnecting the battery, then start it with a known good maf. Did you check for vac leaks, from the lines under the intake manifold?

[bonestock240sx]

its not a vaccum leak. 100% its not a vaccum leak. i just reset the ECU and that didnt do anything.

[jetroy240]

if the wiring & connectors checks ok, try to swap a known good ecu. The driver (transistor probably was damaged)

[bonestock240sx]

would the wiring and connectors be affected by spraying the cleaner through there. im greatful for all suggestions. but everyone has to remember what i did and the problems that are arising. i know that 240sx are carbon build up machines so chances of knocking stuff loose it very high. how do i check if i messed up a sensor. like where do i look. this is a bummer. should of just left the damn car alone.

[jetroy240]

sometimes , old cars, when u touch those connectors or wiring, they are maybe corroded, brittle already, will cause open circuit, make sure the terminals are really snug, when u plug it. Try to find a dummy terminal, male terminal like the one on the MAF, same thickness & width & slide it through the MAF connector, make sure they are coming- in on each, the same 3 terminals of the maf. They should be snug. If it's loose, u will get poor connection. Make sure u got 12 volts on one of the wire. These are the standard operation procedure when tackling a maf sensor code. Either it's the maf sensor, the maf circuit wiring or connector or last resort, it's the ecu.

[bonestock240sx]

alright thanks guys for all the help i guess ill just start working on the information i have got. keep the info coming though!

[rroderiques77]

THROTTLE BODY, THROTTLE BODY, THROTTLE BODY!! remove intake assembly to the throttle body, spray intake cleaner on a rag and wipe around in the throttle body BEFORE opening it. make sure it is clean and no debris is going to fall into the manifold when u open it....then open it, and wipe clean the throttle plate completely, including edges....theres probably gunk on there preventing it from closing completely...if that doesnt solve the problem, then check throttle cable, linkage and connections

[bonestock240sx]

UPDATE! this is what i have done so far from beginning to end1.) ran intake cleaner (messed up and caused the problem we have now)2.) went to NAPA and got MAF cleaner (didnt change much) however the first time i did it it noticably dropped the idle but returned to normal. 3.) checked MAF to make sure connections were good everything was fine4.) had ordered a CAI (cold air intake) a month ago and finally got it so i installed it.5.) Cleaned the MAf again with cleaner no change.6.) Drove it for a week seeing if whatever was the problem would just go away or work itself out7.) Went and tried 3 other MAF sensors that came off working 240sx car and a nissan Maxima (interchangeable) no change.8.) tried to adjust idle and i screwed it all the way in and out and there was no change in idle.9.) checked ECU said code 12 (MAF sensor and circut)10.) reset the ECU11.) still the problem exist12.) disconnected the O2 sensor didn't change idle13.) tried to adjust idle screw again still no change.14.) took out idle screw and sprayed the cleaner in there and caused it to start surging but i drove around the block and it went back to normal15.) cleaned the throatle body and throatle plate. no change16.) put it all back together and no improvement so whats next. should i take off the whole IACV component and clean it all out? or any other ideas? please let me know. thanks

[s13wrencher]

have you try'd tapping the TPS (throttle position senser) sometimes that will get it to work or put a new one on there only about 20 bucks that might be it

[s13wrencher]

or try your pcv could be cloged more or less just given you suggestions

[jetroy240]

Make sure ur swapping the correct year maf for ur 91 S13, not unless the part numbers are the same w/c I'm sure are not d same w/ maxima maf or older 89-90 S13, if ur sure d maf is ok, probably shorted the maf while spraying w/ cleaner & knock-out the ecu driver(transistor) for maf signal return wire. I would check the signal wires at maf when it's running & KOEO (key-on-engine-off). 12 volts or more at Black/white wire, approx. 0 volt at black wire (ground) & between 0.8 v-1.2 volt at white wire (signal wire) at idle. Do not use test light at white wire & black wire or else u may damage the ecu, it's ok to use test light at black/white line wire. A digital voltmeter is best to use. Test it also w/ KOEO at connector removed from maf but test only 12 volts at black/white line wire & ground (black wire), do not test the signal wire (white wire) because it's an input signal for ecu. Good luck.

[bonestock240sx]

alright ill start trying that. if its none of that stuff? then whats next? im glad everyone is very helpful. thanks a lot ill def let you know what happend and the way i came to my solution.

[1KleenS13]

So whats the verdict?????????? If you still have the problem, I still say vac leak. Did you shake the vac lines running over the fan should like a baby??? Mines leaking threw there but I havent changed the lines yet (has speratic idle).

[bonestock240sx]

positive its not a vaccum leak. im not sure what it is yet though. im going for o2 sensor tomorrow. i got an o2 sensor but its a single wire, and the one that is currently installed is has 3 wires and im not sure why because everything that i look at says it should only be 1 wire so i have to figure that out tomorrow to. unless you got suggestions.

[jetroy240]

You gotta fix the code 12 first, specially a hard code. I can only point you to the right direction.

[bonestock240sx]

totally reset the whole ecu manually not by battery cus they just save it. and now i replaced the o2 sensor and it didnt do anything but it was time to change ne way but it was a win win. right now i have my AAC valve off so i can clean it i got it covered in the same stuff that caused the problem. this stuff is hardcore. so it will be cleaned. it looked pretty guncked up inside so i will let you know. in about an hour thanks for all your help.