cukaracha

Hi guys,

My gas pedal occasionally gets stuck (happens at least once per drive). It feels like there's a notch that the throttle body butterfly "clicks" into such that I have to moderately tap/kick the pedal to "unclick" it. The rest of the pedal's travel is smooth.

I've already thoroughly cleaned the throttle body and got a whole bunch of dirt out but that didn't fix the issue. Based on what I can feel from slowly moving the throttle cable, the butterfly hits a course region (feel like rust, but it's not) right before shutting (3-4mm maybe?) and sometimes it clicks shut.

Any ideas?

Poopies

iTrader: (4)

Did you do the cable thing while looking at the exposed throttle plate?

ezone

If the throttle sticks in the closed position, that's either needing more cleaning or possibly needing replaced due to shaft bushing wear. The throttle body doesn't usually get stuck anywhere but the fully closed position.

If the gas pedal feels rough and sticks in the pedal range of usual driving (you mentioned gas pedal pushed down 3-4mm?) that's probably needing a new cable. Cable is cheaper than a throttle body, worth a try?

cukaracha

Thanks for the replies.

Yes, I pulled on the throttle cable while looking into the exposed throttle body.

The gas pedal itself feels fine. The courseness I felt was when I pulled the throttle cable BY HAND slowly to feel for resistance.

I scrubbed out the throttle body very thoroughly so I doubt that that's the cause. I'm hesitant to replace the throttle cable because I'm quite certain that the clicking butterfly is a throttle body issue.

Any thoughts?

ezone

Assuming you did this in the engine compartment, in my mind that should eliminate the cable as it would not be moving in the housing.


If you did this at the gas pedal, then in my mind it still leaves the cable as a possibility.

cukaracha

I pulled on the cable inside the engine compartment, right by the throttle body. I also cleaned the cable itself and the reel that attaches to the throttle body.

Assuming that the throttle body is the culprit, is there a way to repair/fix this problem without replacing the throttle body?

ezone

Try a known good unit first?
Make sure the issue is within the throttle body before dropping a huge chunk of coin on a new one.

TPS problem? It comes with the new throttle body.

If it really is a problem with the shaft bushings, they used to sell bushing kits for common carburetors back in the day, but IDK if anyone sells similar to fit Asian car throttle bodies. Plus the blade screws may be staked in place.

Get a can of carb and throttle cleaner spray and hose off the cable wheels, springs and linkages in the area?

cukaracha

I did more reading in the shop manual and here's a relevant section that I found:




From what I can feel, whenever I push down on the throttle link body just above the throttle stop screw, that's when the "click" happens. Since the shop manual says "Do not adjust" the throttle stop screw, does this mean I should definitely not dink with it?

ezone

Uhhh

What part of did not make sense?

Have the voices in your head read this LOUDER and S-L-O-W-E-R, and keep repeating it until the meaning has sunk into your brain cells.


Then do whatever you want, totally aware that you may end up having to buy another throttle body because you dinked with it and/or it already needed replaced.






Also, I'm totally trying to get some humor into this post.

If you crank the stop to open the throttle a smidge, the TPS value may become incorrect and the minimum air rate will be increased, with the potential to cause odd idle and off idle running complications and possibly other problems.

LBVS. HTH

cukaracha

Cool. Thanks for the reply.

I did a little experiment by sticking a piece of cardboard between the stop screw and throttle link. When I pushed down on the throttle link, it didn't "click" shut the way it normally would.

Instead of dinking with the stop screw ("D o . n o t . a d j u s t . . .. .."), can I stick something in between the stop screw and throttle link to fix this problem? Does the material have to be electrically conductive for whatever reason?

ezone

The effect is the same as dinking with the stop screw, but maybe with the added potential to fall out.

May as well just play with the stop screw instead.

Maybe try 1/8 turn toward opening the throttle and see what happens? Shouldn't need to move it much at all to help the sticking....then you can try to see what else is gonna happen screwy.

cukaracha

Just to clarify, it feels like there's a small notch in the throttle link that the stop screw "sits" into when I push down on it. Admittedly, cardboard induces a much larger clearance than I'm intending. What I'm suggesting is to use a thin piece of whatever (aluminum tape?) to prevent that from happening.

Any thoughts?


P.S. Would you care to explain how exactly the throttle body works? I don't have a good grasp of how the different sensors and components work with each other, and hence the effect of dinking with any of the components.

ezone

Ok the big ol flapper inside is the throttle valve, it regulates airflow through the housing and is directly attached to your foot.

The flapper (throttle valve or blade) is designed to close off the passage completely with almost no air flow around the edges when closed, YET not close solidly against the sides of the housing.
This is by design and is necessary so it does not stick in the closed position, and it works well until such time as sufficient soot and carbon and oil vapor goo has built up in the edges and on the blade to cause interference and sticking in the closed position (hence, the periodic cleaning that is necessary).

If the throttle shaft bushings wear and allow the shaft to move away from the designed location, the blade becomes cocked and can lodge in the bore. Vacuum from a running can increase the difficulty of getting the throttle blade to pop loose.

The computer has accounted for any air that manages to get around the fully closed throttle blade (the idle learning we sometimes speak of) and with the blade closed the computer uses the IAC valve to regulate air bypassing the blade to control idle speed under all other conditions, cold to hot, AC on or off, etc.
The IAC can only close off its air passage so far, so if the throttle blade is slightly ajar the computer may not be able to bring the engine RPM down to normal range.

The TPS (Throttle Position Sensor) is attached to the throttle shaft and on Hondas it is set very precisely to read 0.49v when the throttle is fully closed. I have seen this exact value countless times and it is extremely consistent (99%+) throughout the car line on cars that use cabled throttles.
Many performance and emissions functions rely heavily on extremely accurate reporting of throttle position, and there is very little room for error. If the "throttle closed" value is increased by only a few hundredths of a volt (i.e. staying above say, 0.56v --this is a random figure but it's close to real), the idle program and some other computer controlled functions can go right out the window.

Some tweaking of the TPS might bring its value back in line despite the new throttle shaft position, and if there is a IAB screw you may be able to bring the base RPM down far enough to obtain a normal-ish idle speed even though you have the throttle blade cranked open beyond design, but then again maybe not.

The MAP sensor stuck on the throttle body just measures manifold vacuum, that doesn't really have anything to do with this issue..
Did that answer it good 'nuff?

cukaracha

Excellent! Took me a while to digest everything, but I think I have a clearer understanding now. Thanks!!