4k idle, help!
04-16-08, 08:02 PM
#1
4k idle, help!
i have an 88 n/a, i just installed a header, s5 intake manifold, k&n cone filter, modified my throttle body, removed my vacuum rack, blocked off my egr, acv, and bac. i have all new gaskets on the intake manifolds, and rtv'd every surface all the way to my TB and vacuum capped every unused nipple, there are only 2 lines being used, one to the pressure sensor, and one to the OMP. the only thing is the o2 sensor isnt hooked up, but i know that shouldnt cause this. when the i start the car the rpm's shoot up to 4k and wont go any lower, but runs smoothly. ive tripple checked for any visible vaccum leaks and gone as far as ripping off the intake manifolds to check just incase, and found nothing. someone give me some help here im stumped.
04-17-08, 12:26 AM
#6
'89 GTUs
iTrader: (1)
Join Date: Aug 2005
Location: Tucson, Arizona
Posts: 953
Likes: 0
Received 0 Likes
on
0 Posts
WOW! What is going on?!
Well that's not good. You probably shouldn't be revving your motor that high when its cold, even though you aren't doing it on purpose, id pull the manifolds off and double check everything just to be sure you didn't miss something.
Well that's not good. You probably shouldn't be revving your motor that high when its cold, even though you aren't doing it on purpose, id pull the manifolds off and double check everything just to be sure you didn't miss something.
04-17-08, 12:37 AM
#7
Wow!
I'd check all your timings including CAS. Also take a look at the back of your throttle where you removed the AWS. Make sure nothing is jammed and holding your throttle open.
You said you removed your fast idle screw. Did you mean you removed the fast idle cam? or did you take out the screw that adjusts the idle?
EDIT: Also be sure the pressure sensor is indeed getting vacuum. I could be wrong but I do believe some of those vacuum nipples no longer get any vacuum with everthing removed, but like I said I may be wrong there.
I'd check all your timings including CAS. Also take a look at the back of your throttle where you removed the AWS. Make sure nothing is jammed and holding your throttle open.
You said you removed your fast idle screw. Did you mean you removed the fast idle cam? or did you take out the screw that adjusts the idle?
EDIT: Also be sure the pressure sensor is indeed getting vacuum. I could be wrong but I do believe some of those vacuum nipples no longer get any vacuum with everthing removed, but like I said I may be wrong there.
Last edited by Dr-Zine; 04-17-08 at 12:47 AM.
Trending Topics
04-17-08, 12:49 AM
#8
my CAS was set not more than a few hundred miles ago, ive triple checked, the whole cam was removed, and theres nothing obstructing the TB to keep the plates open, my only idea through some more searching is my injectors could be stuck open i brake cleaned them after i removed them initially to clean them up
04-17-08, 01:29 AM
#11
i installed a header, s5 intake manifold, modified my throttle body, removed my vacuum rack, blocked off my egr, aws and bac all at once, and ive ran the car without the bac plugged in before any of this with little to no change happening to the motor, so im pretty sure thats out, as for the aws i dont see how that could be the culprit to a 4k idle and a glowing header.
04-17-08, 01:54 AM
#14
If the AWS and BAC are gone, then the only possible way for more air to get into the combustion chamber is through the throttle. Did you disassemble the assembly for the primary and inner secondaries, or just the outer secondaries? It's possible that the inner plates are stuck open slightly more than they should be at idle; that is if they were disassembled when you modded the throttle body.
04-17-08, 02:15 AM
#15
well connecting the tps did nothing, except maybe irritate the neighbors at 3AM. i didnt take apart the inner primary throttle plates, the outer plates are removed. however i did tighten up a nut on the set of double throttle plates on the outside of the TB, they seems to be open more than they should be, but i see no way of adjusting them, but i can try using a spare TB 2morrow, much to cold and late for that right now
04-17-08, 02:34 AM
#16
Full Member
Join Date: Apr 2008
Location: OC
Posts: 80
Likes: 0
Received 0 Likes
on
0 Posts
dam, i just bought my 88 NA fc3s. i hope i dont run into this. did you replace your cats aswell? clogged old cats can hold pressure, espeacially if the new header manifold increases exhaust cfm. old cats, new header, puts more pressure and heat trapped in the header... but i dont know if you did. thus choking the engines exhaust flow, ecu reads it as more load causing a jump in rpms...just a thought.
04-17-08, 02:41 AM
#18
Compare the amount they are open against your spare TB. The secondary plates should be all the way closed at idle, but the primary plate will be open about 1mm. If you pulled off the thermowax and fast idle cam, switching the TB out will literally take 10 minutes (no coolant lines to mess with 
).
If you do find that the TB switch gets the idle down, you'll probably still need to adjust the TPS if you swapped it out at the same time. It never bolts back on exactly the way it came off, so you can get erratic idle behavior.
). If you do find that the TB switch gets the idle down, you'll probably still need to adjust the TPS if you swapped it out at the same time. It never bolts back on exactly the way it came off, so you can get erratic idle behavior.
04-17-08, 02:41 AM
#19
could it be my injectors sticking open from using brake clean on them? couldnt hurt to have them out and cleaned anyway. any other ideas, car ran like new before this and id like to see it on the road asap, and for those who may get a kick out of this my g/f decided the car was too loud to ride in after the header install hah.
04-17-08, 02:49 AM
#20
Full Member
Join Date: Apr 2008
Location: OC
Posts: 80
Likes: 0
Received 0 Likes
on
0 Posts
FUNNY, ya my G/F said the same thing. first day i bought the car, the only part i did not make was the manifold, i fab together an exhoust system.
"um babe its too loud, couldnt you have made it quieter?" she insisted we take her honda to eat out.
"um babe its too loud, couldnt you have made it quieter?" she insisted we take her honda to eat out.
04-17-08, 02:50 AM
#21
Leaking injectors would flood it, which would cause it either to not start or just run extremely rich. The RPMs can't go up without extra air in the equation.
At least your car runs with the S5 manifold, hah. I spent 5 days prepping the car, modifying and bolting in the S5 before realizing the vaccuum leak I was getting was from the UIM not seating all the way on the LIM. It's on hold until I can get a grinder piece that will fit well enough to take even more metal off the block. I guess it really has to get ground down a lot to clear the runners.
At least your car runs with the S5 manifold, hah. I spent 5 days prepping the car, modifying and bolting in the S5 before realizing the vaccuum leak I was getting was from the UIM not seating all the way on the LIM. It's on hold until I can get a grinder piece that will fit well enough to take even more metal off the block. I guess it really has to get ground down a lot to clear the runners.
04-17-08, 02:57 AM
#24
yeah i had to take quite a bit off, i dont know if youve purchased the rpm switch for activation yet, but im working on an alternative route as to VDI activation, using back pressure from the exhaust, once i get this sorted out its my next priority, i can let you know how well it works and my setup if your interested
04-17-08, 03:00 AM
#25
thanks for filling me in ill see what i can do to adjust the throttle plates, however even with it running at such a high rpm should the header be glowing like that, if the injectors are leaking, and makign it run rich, running rich raises egt's which seems like it could cause that also