I've got a 91 CRX with a b16 swap, all still obd0. Lately when I start the car when the motor is cold, I'll get a really bad idle fluctuation jumping from 1200rpms down to 400. Sometimes it will even stall out. These keeps going until about 5-10 minutes when the car gets completely warmed up. After it's warmed up, my idle stays around 800rpms and runs perfect. I am throwing no check engine lights as well.

I've already taken the fast idle thermo valve off, cleaned it, and turned the screw all the way back down, took off the idle air control valve off and cleaned the screen up. I've also already done a full tuneup consisting of plugs, wires, rotor button, distributor cap, and fuel filter. I'm completely stumped on what else it could be.

 

My lsvtec did that til I added more coolant and "burped" the system.

 

Its your Idle Air control valve on the back of your intake manifold Try to clean it 1st if that doesnt work Go to the junk yard

 

ok, i'll try adding coolant and bleeding it. i've already cleaned the iacv last night. sprayed carb cleaner through it for about half an hour, then let it sit for about an hour to let it dry out.

all this stuff started after i did a fuel filter and originally turned the screw in the fast idle thermo valve back the other night.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ak_ef9 &raquo;</TD></TR><TR><TD CLASS="quote">My lsvtec did that til I added more coolant and "burped" the system. </TD></TR></TABLE>

yes do this....lmao @ burp i never heard that term used hahahahah!

 

lol, i just added coolant and bled the system. now i've gotta wait a while for the car to cool down to see if it did the trick

 

ok, i got a chance to let it cool all the way down and start it up. most of the fluctuation is gone, but it still has a little bit when cold. i'm thinking of replacing the fitv, or just picking up an itr tb and bypassing it completely.

 

1. Separate your intake tube from the TB and look inside, you will see 2 holes. The top goes to the IACV and the bottom goes to the FITV.

2. Start your car and let it warm up to normal operating temperature (fan comes on), then plug the FITV hole, there should be ZERO to VERY MINIMAL suction. If there is suction after warm up then there is something wrong with the FIT valve, turn the car off and let it cool down.

3. This is where the manuals tell you to change the FIT valve with a new one, but there are actually a couple of things you can do to restore your old one. First things first, this is what the FITV looks like, it's attached to the underside of the TB or in some models it will be attached on the manifold right under the TB and it may have 2 coolant hoses, mine had one on the FITV and one going to the IACV from the TB (channeled through the FITV):

4. Disconnect any coolant hoses, vacuum lines, and electrical connectors that may be in the way of the back of the FITV (make sure you mark them so you know where to reconnect them). Now look at the back of the FIT valve, there is a flat plate held down by 2 screws, you'll be removing this plate. Due to the limited space/visibility I used a mirror and an elbowed screwdriver to take it off, you can also use an 8mm socket:

Inside is the end portion of the spring loaded valve, held down by a white plastic piece with 2 slots on either side:

5. This piece is threaded like a screw and sometimes it will unscrew over time, creating too much slack on the spring of the valve and therefore causing a vacuum leak. Screw it back in with any tool that fits the slots. Screw it in tight but don't overdo it.

6. Replace the plate and reconnect everything you had taken off.

7. Repeat the procedure for checking suction at the FITV hole on the TB [STEP 2]
if your if the problem is fixed after you re tighten the FITV, and the problem comes back a while later just replace the FITV! Good luck

 

I've tightened down the FITV twice already, and I still have my fluctuation of idle... I'm just going to replace the whole unit. I've got a spare TB in my basement

 

well that sounds like a plan! haha but have tried plugging the IACV hole and/or the FITV hole in the throttle body on the left side. bottom hole is FITV and top hole is the IACV so you know if they're just bad!? all you gotta do is take off your intake off the throttle body and use your finger or tape. and obviously check it well your cars on! if idle doesn't fluctuate then then there's ur problem. up to you buddy! Good Luck!!

 

In response to the FITV, does the 97LS motor have that?

 

i'm not 100% sure but pretty damn close that 96 tegs and up do NOT have FITV's... but if you wanna check just take off your intake and see if there's one or two wholes on the left side of the throttle body. if only one then you only have a IACV. well your car is on just put some tape or your finger to cover the whole and if your idle is not fluctuating then you need to take of and clean you IACV. Good Luck!!

 

thanks, i'll try that here in a bit...

also, to the guy who asked about his 97 teg, obd2 vehicles do not have a FITV, only our obd0's and obd1's... they got rid of it in 96

 

No problem! Any updates? and did you clean the FITV when you took it off the throttle body?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88SeeOurEx &raquo;</TD></TR><TR><TD CLASS="quote">No problem! Any updates? and did you clean the FITV when you took it off the throttle body?</TD></TR></TABLE>

Not yet, tomorrow hopefully I will mess with the car a bit, since I've been working the past few days. I did clean the FITV when I took it off of the car. I'll post up tomorrow after I mess with the car a bit.

 

Well, finally got around to checking the FITV today. I plugged the hole off in the throttlebody with my finger with it running at operating temperature. Sure enough, it's got a lot of vacuum. I've got a used FITV I got off of a buddy of mine. Gonna throw that on this weekend, and hopefully my problem will be fixed.

 

sweeet! hope that your problem's fixed once you change it out!!! may be a good idea to clean it since it'll already be off! good luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88SeeOurEx &raquo;</TD></TR><TR><TD CLASS="quote">sweeet! hope that your problem's fixed once you change it out!!! may be a good idea to clean it since it'll already be off! good luck</TD></TR></TABLE>


X2 for the cleaning and the luck

 

Thanks everyone. Gonna tear it apart when I get home from work tonight, also going to install my tokico illuminas and ground control setup, as well as replace my front crossmember, due to the bushings being gone. I'll let everyone know the results

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sloweh3 &raquo;</TD></TR><TR><TD CLASS="quote">Thanks everyone. Gonna tear it apart when I get home from work tonight, also going to install my tokico illuminas and ground control setup, as well as replace my front crossmember, due to the bushings being gone. I'll let everyone know the results </TD></TR></TABLE>
Fosho... no problem!! and thats gonna be a nice little suspension setup there!! good luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88SeeOurEx &raquo;</TD></TR><TR><TD CLASS="quote">
Fosho... no problem!! and thats gonna be a nice little suspension setup there!! good luck </TD></TR></TABLE>

i hope it's going to be a dramatic increase from my tokico blues/eibach pro kit that's on it now.

but as for updates, nothing yet. my roomate left his jeep parked in the driveway blocking the garage and had his keys with him, so i couldn't get it in the garage tonight. i've got all day off tomorrow and i don't have to work until 4pm on tuesday, so i'll be doing everything to it tomorrow. new crossmembers, rack and pinion, fix the fitv, suspension, and new lcas

 

Update: Yesterday I got everything torn apart, noticed the rear crossmember had a 6" crack by the motor mount, which I replacing it anyways, but I couldn't believe how big that thing was. The new crossmember and rack is in now, but I didn't have an extra set of hands later on to bolt the transmission mount back up to the mount bracket on the body of the car.

I also noticed on my 4-2-1 header, one of the downpipe runners is smashed, so now I have to order a new header. Does anyone know if a 4-1 2.25" header will clear the factory front crossmember on a b16 running hasport mounts?

Edit: Found out I shouldn't have to hack into the front crossmember...and a buddy of mine has a brand new 4-1 header that I'm picking up tomorrow


Modified by sloweh3 at 12:35 AM 11/5/2008

 

niCE! thank god for friends!

 

Well, the friend of mine bring me the header bailed, so I'm stuck running this crappy airmass header still...but I finally got the car back on the road after doing all the work to it. All I can say now is WOW! This car is so responsive now. The new suspension handles 10x better than the old, the poly bushings in the front eliminated all of the wheel hop. And the fast idle seems like it's fixed. It hasn't fluctuated since. The entire time I drove the rex today, it put a smile on my face the whole time.

Thanks for the advice everyone.

 

good **** bro! congrats!! Fly low!! haha