i recently bought a 91 CRX with a swapped dohc zc. i took a look inside and at the throttle body i saw this



i have no idea what connects to it. The issue is the car idles a little rough, and when starting up tends to stall out at most once. feels like its surging.



can someone tell me if this is even the right TB??

heres another pic.



if you need more pics or have any other questions, ill try and answer to the best of my extent. thanks.

 

i have the same thing on my zc its to help with high idle on cold starts

 

so you just left it that way? i thought my hoses must have been mixed up, engine is surging a little but, slightly rough idle. plus i have extra hoses laying around near the firewall.

 

you have a picture of how the vacuum hoses are supposed to be hooked up?

 

i compared a pic of my dohc zc to yours, and the thing weird about yours is how on that part thats to the left of the throttle cable, (dashpot? or whatever its called), how you have a thing coming off the top of it, which you have a hose connected to leading to the left of the pcv hose on the intake manifold, and on mine it only has the metal tube coming off the bottom and thats where the hose is on mine that leads up to the intake manifold connecting at left of pcv hose,

do you know why theres two different metal tubes coming off that part ?
it almost seems like they would do the same thing since they are leading from that same part?, have you ever tried switching and putting that hose connected to the thing coming off the bottom instead, to see if things run any better ?

as far as vacuum diagrams and all that, i had all the links but can't find where i had them, but if i were you i would just go to thezcr.com, and search there, cause i found posts explaining exactly what supposed to be connected or not connected on the zc, like said the two holes on back of intake manifold should be plugged up, and not needed, and usually means the motor was taken off an automatic car, and it explained about the skinny black hoses which are on the firewall behind the intake manifold, that come out of those little black cylinder-shaped plastic things, it showed how they supposed to go, and one of them does'nt connect to anything, and other is, etc . . .,

and as far as idle, i had a problem recently where mine was idling high, and it happened after i cleaned out my throttle body and also cleaned out the IACV (intake air control valve),

before it was idling good, but i ended up finding out my throttle was getting stuck and not closing all the way, and i adjusted the throttle cable, and lubed the stuff up around there, and tightened that nut on the throttle pulley thats 12mm towards right, , and also put rtv silicone around the gasket for the IACV so its sealed good in case it was that, and then afterwards i set my idle, first putting to base idle while IACV was unplugged, and then turning car off and plugging IACV back and then reseting ecu, and starting up and let idle 15 mins so the ecu adjusts it to normal idle of 800-900rpm,

and it was better after, but i still notice it idles over 2000 when i first start it up, and got to drive for a while and after turjning off and starting up 2nd time then its finally down to the low good idle, but it surges up some also when pressing brake and clutch, and does'nt always go right down to the low idle all perfect, but it also matters if its cold weather out or not, cause usually idles higher if cold, but mine idles lot better when warmer,

but yeah everything looked like mine on your intake manifold and TB except that part coming off top thats like a metal curved tube, but ask on zcr.com and they can tell you

make sure throttle cable deflection is the right measurement, i think it said between 10-15mm at the part to left of rubber where it is like a silver cord that has slack if you pull it up or down

 

Adjust your idle screw to prevent it stalling out on idle

 

Don't mess with your idle screw unless all else fails.

Check out your IAC for an irratic idle. It might need to be cleaned or maybe the gasket is leaking.
Check for other vacuum leaks as well.

Does it hesitate when you accelerate?
Is your CEL on?

 

When i was running that throttle body, i removed that vac dashpot and capped the hole in the intake manifold.

You don't need it, most models didn't have it.

 

i thought that vacuum dash pot was there to keep the throttle open a tiny bit when the throttle goes from wot to closed to keep the rpms from dipping too low

 

hi everyone thanks for the replies, so yesterday after work soon as i got home i took the throttle body off and cleaned it, also took off the IACV and cleaned that and checked that. i put everything back on, turned it on and it idles smooooooth.

BUT when we took it for a test spin around the block, lets say when i shift at lower RPMs everythings fine, but when i shift from 1st to 2nd anywhere higher than 3k rpm, that instant it goes from 1-2 gear in neutral, the rpm jump up to 7k WTF?? then goes back down....so weird, it did that about 3 times but not always at 7k rpm.

 

oh and one more thing, why on earth does my dashpot have two connections??? anyone know anything about this?

 

You should try connecting the dashpot with a T connector with the other manifold out, or you may be able to plug one of the holes. It wont cause any harm, someone must have swapped the dashpot from some other engine, my DOHC ZC only has one off the dashpot.

 

First, you do not need that part.
The purpose of that dashpot is to keep the throttle open just a tad at certain RPM making it a tad easier to drive. Basically, it keeps the RPM from falling as quickly between shifts.

You can find this posts about this dashpot commonly found on JDM B16s as well as some D16A6s.
You can search and find people with the B16 asking what this thing is - some engines have it, and some do not.

The port on the bottom doesn't hook to anything. It just allows the extra air in when the diaphragm is working.

It could be possible that yours has a hole in the diaphragm which is allowing too much air to pass through between shifts.
Disconnect the black hose going to the dashpot and plug the intake manifold.
If the problem goes away, then I would suggest you don't bother replacing the dashpot. Waste of money for a nearly useless part.

 

ok when i get the time today i will remove the dashpot completely and i will let you know how it goes. thank you for the replies everyone.