Ajusting my primary throttle valve?
 

I've been having idle isues for awhile. I ajusted the TPS and couldn't find any vacume leaks. At idle it revs to 1600 rpm then drops to1400 over and over. If I turn the throttle in front of the TB the opposite way of giving it gas, the idle drops to 800 and idles good.

So today I took a look inside the throttle body and saw the the primary valve is open a bit at idle. When I turn the throttle backwards so it idles good the valve closes some, it looks like all the way shut.

My question is, is the valve suppose to be open a little like how it is, or should it be shut? If it's suppose to be shut how do I ajust it? I don't want to just start turning idle screws and mess it up worse. Any help would be appreciated.

Do you have any mods done to your car? turbo or non turbo?

Not really any mods, just an exaust the previuos owner put on, single, cats removed, one muffler. Where is the air screw exactly?

I'm looking in my haynes manual, is it the fast idle ajusting screw? It also says if the clearence between the primary throttle valve and the wall of the throttle bore is incorect(like mine), to bend the tab( inset). I don't know what the tab is though.

Is it turbo? makes a huge difference

My bad, no it isn't turbo, I should of said that. It's an s4 N/a with the OMP removed.

had the same problem with mine, take the throttle body off and look on the backside and find the bottom adjusting screw take it all the way out and put a small washer on and reinstall the tb. thats what worked 4 me anyways

Thanks man, I'll give a shot tommaro.

The FSM in the fuel and emissions section clearly shows how to set the gap of the primary throttle plates. It has a ...picture.

I turned in the ajuster screw on the top/front of the throttle body. If I rev the engine it will surge a couple times when it comes back to idle but then it will settle down and idle good, but it's still high, like 1500 rpm. I checked the TPS again and it's in check.

check your dash pot 2, mine was 2 far forward and was keeping the throttle open a bit

Sorry, the throttle adjustment screws are on the BACK and bottom side of the throttle body on series four cars.

As mentioned in the thread just above this one, you need to check out the water thermowax's adjustment which is also located on the BOTTOM/AFT side of the throttle body. The piston on the water thermowax can cause the throttle linkage to stay open a touch if that item is not rigged right. See FSM.

The TPS cannot be set right if the water thermowax is holding the throttle linkage open any at all.

The FSM is free and online and the FUEL AND EMISSIONS section shows how to adjust the above parts.

There is a air adjustment screw on top of the dynamic chamber..........but you askes about throttle plates not idle adjustments.

Well it is the idle thats the problem, I just thought this might be what was causeing it. I've been trying to slowly narrow everything down till I find the Problem.

I don't know what the dash pot or the themowax is but I'll look it up. If one of these things is the problem is it going to drop the idle down too or just level it out? I've been tearing my hayne's manual and the forum up trying to figure this out.

FSM= Factory Service Manual? I think I saw a link in the FAQ I'll go check it out. Thanks for your help guys.

IF the thermowax is holding the throttle plates open and causing the rpm over 1200 at idle, then adjusting the water thermowax will make the primary throttle plates fully close resulting in a lower idle rpm and also by default make the engine run smoother.

Anytime the engine is over 1200 rpm the ECU advances the timing which in turn makes the idle rougher.

IF the water thermowax was/is causing the throttle linkage to open the primary throttle plates ........then after you correct this problem you can now rig the TPS properly with a fully hot engine which in turn means the idle will be better.

TPS ...water thermowax....throttle linkage are all tied together at the hip. One effects the others.

NOT saying that the dashpot isn't the problem. You might just unscrew it and see if the idle changes.

I unscrewed the dashpot and it did nothing so I put it back how it was.

Where is the thermowax located, I can't find it in my haynes manual or in the FSM. The FSM shows a water thermo sensor. Is that the same thing? If it is it doen't show how to ajust, just remove and inspect.

Located on the back of throttle body near the firewall. It's very close to the dash pot as in between the dash pot and the other side of the throttle body. Check the online FSM for detailed info. It is in such a hidden area that a small mirror is often used to check the linkage associated with the component.

http://www.teamfc3s.org/main/factory...SYSTEMS_NA.pdf

Thanks, I found the dashpot. Do you have to remove the TB to ajust it beacause I got the smallest screw driver I have and I still can't get to the ajustment screw, and thats with the dashpot romoved.

How about looking at the area from the driver's side, helps if you're right handed, and use a mirror to check to see if the unit is working properly with respect to the "fast idle cam" as the engine warms up before making adjustments.

Do like the Satch mentioned above with a fully HOT engine. It's difficult to find even if you've seen it before, but make sure the cam/rollpin are seperated when the engine is fully hot. IF they are seperated, that's good.

I never found a easy way to adjust a non turbo with the throttle in place. I remember trying to use my 2 and 1/2 foot screwdriver once from under the car......with small success.

Sorry, that was a typo in my last post. I meant I found the THERMOWAX. I can just barley ajust the screw from an angle.

Do I want to go in or out to lower the idle and close the valve? I ask because it takes like a full minuite to do one turn from the angle I'm at and it doesn't seem to be changing the idle. And yes the engine is hot, my burnt fingers can vouch for that. lol

Also, what does it do, Is the rod going into the thermowax suppose to move or anything when you give it gas, or does it just hold the linkage in place at idle? I can see a Peice that looks like its stoping the linkage from closing as much as it needs to but it doesn't look like ajusting the thermowax is going to move it.

http://img109.imageshack.us/img109/499/fastidlecam.jpg Cold engine position

http://img297.imageshack.us/img297/7...stidlecam2.jpg Engine warmed up

Start looking at page 4 in the below link. Post #87 is important!

https://www.rx7club.com/showthread.p...am+pics&page=4

I ajusted the screw all the way in, and then all the way out tell it was finger loose and nothing changed.

In that pic it looks like the bracket the ajuster screw is on moves, mine doesn't, it's on a solid bracket. It has to be the thermowax though because it's right under the dashpot and the screw is sideways like that. Thanks for the link, my car is idleing pretty much exactly like that so I'll read through it and try to figure it out. Thanks again you guys I really appreciate all the help.

See pic below.

As in this screw?

http://img15.imageshack.us/img15/904...djustscrew.jpg

i didn't read through all of the crap but first of all, the screw on the front of the throttle body is for the secondaries(the double set of butterflies) and they should be nearly completely shut, the screw is to only make sure they don't slam shut and cause the throttle to bind up.

second, the proper way to adjust the idle is with the idle adjustment screw ON TOP OF THE THROTTLE BODY IN THE CENTER OF IT, under the black cap.

third, reset all the rest of your adjustments that you screwed up in this thread back to how they were. you had it set properly in the first place but were reading things incorrectly about the SECONDARIES being open and were worried for nothing.

if the rest of you can't understand what someone is asking then try to be sure you do before causing people to further make more issues for themselves.