revs up drops revs up drops..TPS/IAC???....
 

i changed my oil today(trans/engine), put my cold air intake back on, cleaned the throttle body out with throttle body cleaner... after all this my car sputterd a little from the carb cleaner than warmed up and began cycling reving to 2100, than dropping to about 500 and doesnt stop doing this... i dont think its a vaccum leak but i did replace all the lines with stronger toyota 5sfe hoses, my buddys turbo mr2 did the same thing and after we swaped out his TB it ran ok again im thinking its the Iac/TPS but i cant be certain if anyone has had this problem please help me out...

Re: revs up drops revs up drops..TPS/IAC???.... (R6E6I6D)
 

bump because my car did the same thing

yeah, it's most likely your IAC located behind your intake manifold. It has two coolant hoses coming out of it. It tends to get stuck and your computer wigs out during idling. Pull it off and spray the insides with throttle body/carb cleaner. do that a few times and let it air out. Should fix the problem.

Re: (carma_626)
 

https://honda-tech.com/forums/images/smilies/emthup.gif helped me

could be the fast idle thermo valve.... right under the trottle body not sure what year your car is cause the dont have those in the 98 or 99 and ups i believe..... what happens is there is a float in the fast idle thermo valve that backs itself off and thats what happens it give you an irregular idle like that

Re: (whiteJDMdc2)
 

that happens to almost everyone i know that used tb cleaner...i dont know exactly what happens but what i did was reset my ecu and went away for about every 20 mile intervul...i wished i had more answers for you, but it DOES go away. BUT, it took about 50 miles or more then never happened again. a month later, i got curious on how clean it was and i ended up taking apart the whole IM then found out that some gunk was blocking a sensor..(somehow, it didnt idle bad before removing the gunk)

hope this helps somehow

Re: (VTECb18c)
 

i took off all the goofy ass bullshit hanign around the IM and sprayeed them all down adn put it back to gether and resprayed the TB it stumbled a little when getting started and rev to about 22k and just chilled there for about 3 minutes than continued the idle fluctuations, i am going to check the air boooooooost vavle and see if there is a problem there i also checked my TPS for running voltage adn she checked out fine... im gunna go to school and hook her up on a scope and see if tells me anything... also the vehicle has a horrible rich misfire while its doing this BS idle thing cause the exhaust gives small pops (although my car backfires like a beast while up there in the RPM's) but it also stinks like Hydrocarbons if anyone can again give me a hand id appreciate it https://honda-tech.com/forums/images...es/emsmile.gif

Re: (R6E6I6D)
 

Someone had previously mentioned this already but it's worth your time to take a second look. If your car is odb1 I would look at your FITV, FIV fast idle thermo valve, fast idle valve, located just under the throttle body. The valve inside shakes/unscrews itself due to engine vibration over time. A Notorious and easily misdiagnosed problem. A simple test will tell you if that part needs to be adjusted.

Engine off..temps moderate-cool remove your intake piping. Just inside the TB are two holes. 6 and 8 o clock I think. At this time I cant remember what hole it is im thinking the outer hole though. So try both! Now that you know where the holes are start your engine. Now, plug a hole, one at a time. you should feel a vaccum over the right hole. when you locate it, seal the hole with your finger. If the idle stops surging.. MAGIC! It's that FIT Valve.

If that worked, you'll need to remove the valve to fix it. It's held on by 3 bolts under the TB. Use a small socket wrench and have a 1" extension handy. Upon removal coolant will leak.. this is normal. Once you remove hosing and bolts and the valve is free.. you will need to remove the plate on the side held by two screws. On the inside lies the valve. (mine just fell out) you will need to screw that valve back in all the way untill the rubber nipple pushes itself out and creates a seal. Use some sort of tool because hand tightening wont get it all the way down. I personally used a flathead screwdriver. Rebolt and you should be good. https://honda-tech.com/forums/images/smilies/emthup.gif

Re: (Medek)
 

isnt that a small wax valve that once heated up to a certain temperature it expands closing the gap and allowing the idle to drop back down to a regular idle... i thought it just was for cold starting, i will check that out though thanks and im gunna spray a bunch of cleaning shit into my iac which is the other hole (right?) and hope hte second cleaning helps if not drive it till i get my new motor in there cause i got a new LS and dont wanna put more money into my beater motor

Re: (R6E6I6D)
 

Thanks Medek, I had the same problem, and I just went outside, took the throttle body off, and sure enough it was shaking around inside... Tightened it back up, and it's idling fine...

Re: (95ILS)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95ILS &raquo;</TD></TR><TR><TD CLASS="quote">Thanks Medek, I had the same problem, and I just went outside, took the throttle body off, and sure enough it was shaking around inside... Tightened it back up, and it's idling fine...</TD></TR></TABLE>

No prob yo... that rev used to annoy/embaress me so badly. Glad I could help.

Oh and back to the poster, spraying carb cleaner into the hole leading to the IACV wont clean it very well.. you gotta unbolt it (2 bolts) on the back/upper side of the intake manifold. Inside you'll see a wire screen. Spray/Clean that up that way.