Carb possibly?

[AccordinglyNM]

so, here is my delima. I drive an 87 accord DX, and for some reason, it will not retain it's proper idle speed. It should be at 800 RPM, and at times it is, but some times, it will just jump up, pretty drastically, some times higher than 2000 RPM's...Now, I know the fast idle is set for 2000, but why owuld it be jumping that high out of now where? and why would it be doing it when my car is running at normal operating temperature? I am thinking maybe I got a carb problem? but I cannot be sure, so I came here. I hear nothing but good from you all from my brother, AccordinglyAZ, so i figured you would be my source of help. I even took the car into a shop for them to run a diagnostic, and they said they cannot find anything wrong.. Any help would be greatly appreciated.

[ChaseR]

As I suggested before I think, there has to be a Vacuum leak somewhere. But some of these guys are waay more talented than I am regarding these motors.

NOt sure why anyone else hasnt respoinded but like I said on myspace im going to start hunting down EFI parts for you, we might end up doing the conversion.

[DDRaptor]

well yeah that's defintly some sort of vacuum leak. I know very little about the complex vacuum system so what i would suggest to you is do run some carb cleaner and that will rule out the carb .

[A20A1]

What the coolant gauge says may not be accurate at all times.
To rule out low coolant not reaching a thermovalves I would check the coolant level in the radiator (when the car is cool).
Things like a bad thermostat or coolant pump or a bad thermovalve can also be culprits.

The thermovalve is a vacuum leak but one that is supposed to exist only at certain engine temps. The vacuum is broken and air allowed in via #17.

Anyways after checking the coolant take a look at these other threads.
A vacuum gauge is helpful, I think more helpful then carb cleaner though you still need carb cleaner to hunt down leaks.
http://www.3geez.com/forum/showthread.php?t=48569

I know I made this thread for high idle but some things still apply
http://www.3geez.com/forum/showthread.php?t=53700


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[AccordinglyNM]

Well, about a year ago, my thermo vavle snapped in half some how, and I replaced that, but I will check all my coolent levels and such, and see if they are low, I have not noticed them low the last time i checked, but I will head out to the car and check again now. Also, where will I be able to find a vacuum gauge? Thanks for all the help.

[ChaseR]

Jason, I don't think you will need a Guage to see if you have a leak, Just listen closely, and spray carb cleaner on all the little hoses to see if you have a leak. you will see little bubbles.

[A20A1]

Listen for changes in the engine rpm.



well yeah that's defintly some sort of vacuum leak. I know very little about the complex vacuum system so what i would suggest to you is do run some carb cleaner and that will rule out the carb .

You don't spray carb cleaner into the carb when testing for leaks though because that will automaticly change the engine rpm... you want to avoid any cleaner getting into the carb so that only the leak sucks in the cleaner and you can pinpoint it.

You do want to spray at the base of the carb though, again being careful not to spray into the carb, or so much that a clound of carb cleaner can get sucked into the carb.


Also spay the intake manifold where it meets the head.


The PCV valve can also cause trouble if it's leaking or is clogged with oil deposits.

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[AccordinglyNM]

I cannot hear any leaks tho Chase, and I tried soapy water on the hoses, like i do when looking for a whole in my tire, and no air bubbles...Possibly something is clogged up?

[A20A1]

vacuum is displaced air so it'll suck in air and may not bubble like a tire would which is under pressure and releases trapped air.

[AccordinglyNM]

What I was thinking of doing, was taking each vacuum hose off one at a time, and blowing threw them with the end clogged so I could tell if it had a leak. Do you think that would work A20A1?

[Accordaone]

Sears sells a combination vacuum gauge/pump that also can be used to bleed the brakes. Works great.

[ChaseR]

Jason, If you can't afford the Guage from Sears I guess you can try your theory, It can't hurt I guess.