Problems after Throttle Body Cleaning
 

Today I changed the air cleaner filter(was very dirty) and cleaned the throttle body (On-car). After this, the car started idling at 1500rpm. The normal idle is around 700rpm. I disconnected the IACV and tried to set the base idle at around 650rpm. After screwing the idle screw all the way in, the idle remained at around 850rpm. I went thru the procedure of stabilising the speed at 1000rpm and slowly releasing the gas pedal.

The thing is that after reconnecting the IACV and clearing the ECU, allowing it to idle for about a min without touching the gas pedal, the idle speed is around 720rpm (within specifications!) problem is the idle is rougher than normal and there is a noticeable lack of power. Throttle cable is properly adjusted with appropriate slack, if the FITV was leaking the problem would have been there before and the idle would continue to be high with the IACV connected. Same goes for vacuum leaks. Am I missing something here?

RE: Problems after Throttle Body Cleaning
 

Did you clear the ECU by pulling the 7.5 amp radio fuse in the engine bay box for a minute?

Since you took of the throttle body, you had to add some coolant. Did you bleed all of the air out of the system via the valve on top of the thermostat housing?
If I remember correctly deserthonda always mentions that you should take out that idle screw and clean that passage.

A leaking FITV should raise your idle and ususally it fluctuates. You can try covering up the FITV port inside of the throttle body with your finger when the engine is warm. There should almost zero vacuum on that hole. Covering both the FITV and IAC holes should cause the engine to stall. If not, then you have some sort of air leak. Did you replace the TB gasket? Did you clean the IAC valve with throttle body cleaner?

RE: Problems after Throttle Body Cleaning
 

Yes, the ECU was cleared by pulling the 7.5 amp fuse. I did not remove the throttle body...cleaning was done by removing the air hose and spraying Amsoil Power Foam directlyinto the TB while engine idled. I know about cleaning the idle screw but that's usually done if idle is too low?....i'll give it a try anyway. I'll also try your method of testing the FITV.

I'm also thinking that maybe the ECU is adjusting the timin....making it impossible to set base idle? I have searched diligently under the glove compartment and cannot find a Service check connector to jump.

RE: Problems after Throttle Body Cleaning
 

Maybe some dirt dislodged & worked into the passageways for that idle adjuster screw.

Right RPM but rough running? What about plug wires, cap & rotor? Did you clean them (with what)?

RE: Problems after Throttle Body Cleaning
 

The plug wires and distributor paraphrenalia are ok...in fact I changed the dist o-ring a couples weeks ago and took the opportunity to clean up the contacts and rotor. Car was operating fine after. The only reason why I decided to clean the TB is because I was changing the air filter and had the time.

What is really puzzling is the impossibility of setting the base idle while ECU controlled idle is rock solid at 720rpm ( under all load conditions). Later I'm going to clean the idle screw and test the FITV...perhaps there is a small leak

RE: Problems after Throttle Body Cleaning
 

By the way, if dirt had gotten into the idle screw passageway, wouldn't that result in low idle? Logically, it would seem that there is some small air leak somewhere

RE: Problems after Throttle Body Cleaning
 

I had the same problem. The car is missing erratically. Just keep driving the car until all the crap has worked through; it might take a few days. You may want to throw a new set of plugs in once it starts running better. Next time do yourself a favor and remove the TB to clean it, I know I will.

RE: Problems after Throttle Body Cleaning
 

Boy! those are my sentiments exactly. I'm still kicking myself for not taking the necessary time to do the thingproperly. Shortcuts never work...just lead to more work actually. Anyway, the FITV has a slow leak....it is till sucking air after the car has fully warmed up. I'm waiting for the engine to cool down so I can work on it

RE: Problems after Throttle Body Cleaning
 

I'd wait a week and Seafoam it .... it may make it worse at first, but at least it will help the crap work its way out.

RE: Problems after Throttle Body Cleaning
 

as for the service connector for the diagnostic tool hookup try looking under the steering wheel or anywhere in that general area under the steering column or dash, all the ones I check for ppl at work are under there.

RE: Problems after Throttle Body Cleaning
 

I think I may have found the service connector....there is a clipped-onblue holder underneath the glove compartment...it contains two blueplugs; one 2pin and a 3pin. The manual says the connector wires should be grn/wht and orn/red...the 2pin wires are solid brown and red. I'm hesitant to do anything until i'm sure what is what

RE: Problems after Throttle Body Cleaning
 

Yeah, i kinda feel that way...but, the FITV IS leaking....might as well clean and adjust it. I think I may have cleaned out the gunk that was keeping it together!

RE: Problems after Throttle Body Cleaning
 

better to just replace it .... you're not actually supposed to adjust them even though you can.

RE: Problems after Throttle Body Cleaning
 

The FITV can be cleaned and adjusted, but mine was a temporary fix when I did it. For diagnostic purposes, you can try the fix to see if it helps. Here is a pretty good link with pics http://honda-tech.com/zerothread?id=1564019.

If your car doesn't idle properly, you can also remove the IAC and clean it with throttle body cleaner (not carb cleaner). There is a screen between that and the throttle body that can get clogged with carbon.

RE: Problems after Throttle Body Cleaning
 

Ok, cleaning and adjusting the FITV didn't change anything....still a trace of vacuum at the TB port. I understand this is normal. So, I started thinking that I must be missing something obvious...well, in the fully closed position, the valve plate is admitting air. It appears that the accumulated crud was acting as a kind of seal prior to the cleaning. Now, everywhere I turn I get these dire warnings "not toeven think about orattempt to adjust the stop screw". What am I to do?...wait until sufficient crud has built upto provide a seal or, disregard the warnins and attempt adjustment? DH"s opinion would be greatly appreciated

RE: Problems after Throttle Body Cleaning
 

ok, at first you stated the idle was rock solid and 720rpm but there was a lack of power...idle speed has nothing to do with and engine power. how does it lack power?




second, the lower port on the throttle body should have vacuum when the engine is cold and no vacuum when the engine is fully warmed up. it's not normal to have vacuum there when fully warmed up. if it has vacuum there when fully warmed up, inspect the fast idle valve sealing o-rings for flatness or wear. try replacing them first or just replace the fast idle control valve after verifying the cooling system is ok and bled.

third, the base idle screw adjustment you did up top was spot on, no problems there. you did a good job. did you apply white out or touch up paint to the screw to 'lock' it in place? engine vibration can cause it to loosen up and change your setting. the scs connector doesn't need to be jumped on your model to set base idle.

did you check the coolant level? low coolant will mess with all the idle control systems since they rely on the coolant temperature to operate properly. that fast idle valve is simply a thermostat for air.



so, i'm coming to the conclusion that the idle speed is spot on but you feel a vibration. from what you are telling us i'm leaning toward another source of vibration(motor mounts? old stiff radiator hoses, etc?


what do you mean about what you said, "attempt to adjust the stop screw"? i just want to be clear what stop screw you mean before i go into that.

RE: Problems after Throttle Body Cleaning
 

The interest is appreciated. I'm talking about the throttle plate stop screw. Perhaps i'm not been sufficiently clear. It is impossible to set the base idle. With the idle screw fully screwed in, the idle is near 1000rpm...instead of around 650rpm. Even though the base idle is that high, the ECU apparently makes the necessary adjustments and bring down operating idle to 720rpm....problem is, although the idle is steady it is very rough. To smooth it out, I backed out the idle screw one and a half turn, so the operating idle is now around 850rpm, but pretty smooth with good acceleration.

I take your point on the FITV but, i've read several opinions asserting that negligible vacuum is normal...your position is a more logical one and perhaps that's the ideal to strive for

RE: Problems after Throttle Body Cleaning
 

backing out the base idle screw is a bad idea. the base idle could have been 1000rpm because of the leaking fast idle valve. like stated above it can be a leaking valve or leaking sealing o-rings.

so fix that leaking lower porton the throttle body(if leaking when it's fully warmed up) and then try setting base idle again. if the throttle is lightly open thats because the throttle plate stop screw is misadjusted and that will cause a vacuum leak also. does your scantool read the TP(throttle position) sensor? it should be .47v-.49v when fully closed. if it's not, that screw needs adjustment if possible.

RE: Problems after Throttle Body Cleaning
 

It might be that the mechanical stop screw on the throttle needs to be adjusted. The warnings about never adjusting that are because some people try to use that as an idle adjustment.

The mechanical stop for the throttle should not hold the throttle plate open. It should justbe enough to prevent it from wedging stuck closed. (Also, the throttle cable must not hold it open either.)

RE: Problems after Throttle Body Cleaning
 

It is been held slightly open....so, i'm going to bite the bullet and attempt an adjustment