RX7Club.com - Mazda RX7 Forum - yet another damn idle thread (mystery of the funky idle part2)

as posted in the 2nd gen forum................

ok, i tried to find my old thread that some wanted my to post to after i tinkered, but i can't find it. so to rehash.

91 na

car goes through warmup fine, stays at 1.5-1.8k rpms until temp gauge reaches operating temp then stays arond 1-1.1k rpms as if it would slowly lower as temps came up. this idle was always pretty steady, no hunting. i could take the car and slip the clutch to push it down past the 1k mark and then it would drop and start idling at 750rpm as required, still steady. also if i reamed on the car, shifting at redline, it would automatically drop to 750.

as a side note, it would surge when braking it down to 750 before pushing the clutch in, as if he motor was fighting to go past the 1k mark.

so as someone suggested a vacuum leak, i pulled a small vacuum line behind the motor last night and the idle rasied to 1k from the 750 i'd set it at using the clutch to knock it down. so believing i have something sticking, i take the plastic off the throttle body. the bottom plate was a bit dirty so i clean it up with a towel and some wd40 (yes i have small hands). go to put it back together and start it. its idling at 1.5k and i can't knock it down. so of course i'm pissed because now its worse. so i start poking in the bay and find i'd knocked a vacuum line off in the process. plug it in and idle lowers to 1.2k. so looking around again i notice one of the large vacuum lines under the intake look loose. i can wiggle it a little to easy on the plastic so i pull it, car dies. big vacuum leak, lol. so i go inside and get the dish detergent and use the "bmx grip" trick, smear a little on the inside, put them back on and go inside to let it dry. come back out and wiggle the really loose one. won't move under slight pressure so i leave it at that, climb in, start, same shit before i pulled it off. so i just grab the 32 oz mallet and start wailing on this mfer. ok, thats what my thoughts were doing. so as i'm revving it i notice it that i could do something that i was able to do before i took of the plastic intake. if i was to try and hand shove the throttle closed and hold it, it would eventually drop idle w/o using the clutch slip trick. however i used to be able to do it easily, now it would only do it occasionally and always sit at 1k. then the bastard decides to start the idle hunt shit. like 1.2k to 1.8k, rev, rev. james looks at me and says tps. ^%$@^#*&^#^%@&%^#&^@^$@$^!!!!!!!!!! dammit. so he tells me where it is but i'd already guessed it. thing is, i have two. i had also taken and pused these in with my fingers and it affected the car in no way.

now driving it after leaving his house, it has stayed at the 1.5k until warm and then can be knocked down to 1k. so it seems that whatever i did in removing the intake plastic and cleaning the lower plate made the problem worse. it hasn't done the idle hunt again though. just that once. i know this is a long ass post and some might want to go get a popcorn and coke, maybe read it over again. its just pissing me off as i have no true target to work with. my blown struts and falling apart exhaust are easy. i look at it and see its broken. this things like a hardy boy's mystery.

update: ok, i did the starter fluid spray to check for vacuum leaks and have found nothing. when idling high(1.5k), i can pull a vacuum line(smaller) and it doesn't affect it. but i can still drag the engine down with the clutch and it will stay at 800~900 AND ITS ROCK SOLID. if you pull a line, it will raise the idle. wtf is going on here. this is becoming very annoying. PLEASE READ THE FIRST POST. this is not a timing issue. if there is a vacuum leak its well hidden. i figured after i was done with the extra strength starting fluid that i might end up getting some weenies since i drenched the damn thing. no response. i did this at the 1.5k idle and the 800~900 idle. and whih tps do you set, narrow or extended range? are there two on all second gens.