unless he/she poured the fuel cleaner down the intake pipe it wouldnt have affected the TB.

why dont you adjust the TPS you already have - it's not broken...

i have left instructions on how to do this on the previous post page. right after when i told you that it was probly your TPS...

HTH,

t..

 

answer me this...why does the car idle normal when it's warming up then start to surge after a few minutes??? if it was the tps wouldn't it just surge all the time.

 

something i belive to do with the car being in "idle mode"

where it runs off the fuel maps in the computer and ignores things like MAP sensor, O2 sensor, TPS etc

once warmed up it goes into closed loop mode and is a "dynamic" system taking account of all the sensors inputs to determine the correct fuel maps...

re-read this thread from YOUR first post and you will get a better idea of how a Honda engine and ECU interact.

fixhondas has given a lot of really valuable information here - for free! i suggest you thank him imensly as well as all the others who have contributed...

i do indeed hope that it is your TPS, it is a simple thing to fix.

good luck,

t..

PS if not your TPS - we'll have to keep the ideas comming...

 

i have been thanking you guys through out this whole thread...oh well, i'll try it and if doen's work...i'll be back. thanks again

 

i don't think it's the tps anymore...i put a different one in today and got the voltage to be .5V and still idles the same. i am now leaning towards the temperature sensor...maybe the ecu is getting a false temp. and screwing up the idle. just a thought...let me know what you guys think. thanks

 

well, if the TPS is at 0.5v at closed throttle and you are still surging then its prolly not the TPS...

the temp sensor would not lead to a surging idle, only a no start i belive.

what codes are you getting??????????????????????????????

t..

PS can you take a picture of your engine bay so we can see it? this will help HEAPS!

 

what can it be...isn't the idle speed related to the coolant temperature??? thanks again
btw...here are some pics




[Modified by hatchmobile, 4:16 AM 3/8/2002]


[Modified by hatchmobile, 4:16 AM 3/8/2002]


[Modified by hatchmobile, 4:18 AM 3/8/2002]

 

When you put your hand over the TB it should die- you have air leaking somewhere- could be TB gasket, PCV, IACV seals, intake gasket, brake booster, IAT sensor oring, injector seals, cracked manifold, wrong gaskets etc.. With your hand over the TB and engine running- spray carb or brake cleaner until you find a spot where the speed changes. The reason it is ok cold is because there is a calculated amount of air that is supposed to leak past the thermovalve- once the engine warms the ecu tries to maintain @700 rpm with the IACV. Any vacuum leak will cause a hunting idle such as yours. As long as you have @.5 volts at closed throttle- your TPS is out of the picture (for the idling problem anyway). Air should only enter through the throttle body. Also check that your red canister purge hose is hooked up (nipple on top of TB). Pinch it off and see if idle changes. Any hose going to the intake- pinch it off to see if the idle changes.


[Modified by fixhondas, 11:16 PM 3/7/2002]

 

That black hose on top of the TB next to the MAP- where does it connect- looks awfully large! I don't think it would matter though- I believe the purge port is before the throttle plate.


[Modified by fixhondas, 11:27 PM 3/7/2002]

 

thanks fixhondas i will try that tonight and tomorrow...thanks for everybodies help

 

Take your intake tube off and send another pic-

 

i'll do it tomorrow...too dark now.

 

Actually, engine does not die when lower port in intake manifold is sealed.

 

It shouldn't die with that port plugged up.

 

did all the surging idles disappear on the weekend?

whats the secret? is there an update?

t..

 

Sorry, went to Htown for the weekend.

I was told, close off the two ports in the intake...

whichever one changes the idle the most should be the source of the promblem
upper - IACV
lower - Thermal Valve.

So I was going to look into that

btw, whats a working version of a thermal valve supposed to look like or do?
how can I check mine to see if somethigns wrong?

 

a thermal valve (Fast Idle Thermo Valve) is for allowing air into the intake when the engine is cold.

coolant passes through it and this affects a wax pellet which is "open" when cold and gradually closes as the coolant warms up, allowing less air past the throttle...

you can check it by taking its cover off and seeing if it is closed once the car is fully warmed up, there should be a couple of screws holding a brass coloured plate on the back of the valve and a plunger type thingy inside.

stick your finger in and see if you can feel any air - if you feel air being sucked in - the valve is staying open once the car is warm and this is affecting your idle (cause the ECU does not know the state of this mechanical device)

hope this helps,

t..

 

Yes there is a little bit of suction there.
Should I replace it?
Or is it fixable?

 

if you plug it up once engine is warm and your idle problem is still there, then it is not the cause of your problem...

if the bad idle symptoms dissappear when you plug it up - then replace the thermo valve...

t..

 

there is usually a tiny bit of vacuum there once fully warmed. Does it affect your idle?

 

I notice a few post about adjusting TPS's, but can you adjust one on an 86 si stock engine(EW4)? Looks like a cone shaped bolt head on the TPS. Can I simply cut a slot in it for a screw driver?

My problem is that, after car is warm, if I'm driving and let off the gas and press clutch with rpm over 2k she'll stall. Does it if I rap it up and let it drop also. If I catch it and manual "set" the rpm down to 700-800 she'll idle fine.

 

yeah - cut a slot, some may not be screws though, you may have to drill it out and tap a new thread if you think this is your problem...

good idea to test it to see if it is within specs...not sure on older models (id guess they are teh same if it is a PGM-FI ECU...)

t..

 

i still have my idle problem...i'm going to try out another IAC and see if that's the problem. i checked all the vacuum lines in the car and there are no leaks that i can find. i think that it is the IAC...but we'll see

 

Aright, while Im waiting for the engine to warm up, My idle is still messed up...
ever since I fixed the idle screw, when I turn on the engine after its been cooled, It will start at 2k, then slowly move down. As soon as it reaches 1.5k it starts hunting. Also while its moving down about every 20 seconds it will drop the idle for a second and then climb back up to where it was. I popped the hood and when it drops it sounds like a sqeak coming from the rigth side of the engine. What came to mind is a gear slipping? I dont know if thats possible but its all I could think of.

Ill go plug the hole soon and tell you what happend.

 

I believe we have a winner, when I plugged up the thermo valve the surge dissapeared.

Also when I went out to check it, it looks like my idle screw dissapeared.
... Some how.

So I had to plug that hole to.