Throttle cable possible idle issue

[Julius Platon]

Hi, I have a 92 honda civic dx and I ran into a recent problem. I got this car used a few months ago and the engine is a ph12 carbureted 1200cc engine. Up until yesterday my car started and idled just fine. However, I ran into a problem wherein the car would start but as soon as I’d let go of the gas/accelerator pedal the engine would stall and die completely.

I was able to keep her running after the initial start/ignition by applying a constant pressure as i stepped on the gas/accelerator which kept her alive. But as soon as I’d let go she’d die which led me to believe it could be the throttle cable as I may have my suspicions that the cable has not been changed since 1992 and could be stretched.

I’ve tried tweaking the idle adjustment screw to no avail.

Is my thinking correct that a slack on a throttle cable could cause the engine to stall, or could an engine idle just fine with no tension or removing the cable after it is started?

Topic

[college man]

see if this helps.

http://www.ericthecarguy.com/faq/solving-automotive-idle-problems

[Julius Platon]

Thanks a bunch. The idle problems section is actually the first thing I read on this site before I signed up. The video on the free performance upgrade by tightening the throttle cable by Eric is what got me a little confused as it had lead me to believe that despite the huge slack in the cable a carbureted engine may still be able to idle normally and taking up the slack would only have a direct effect on throttle response and not idling.

This has got me stumped because the car idles fine at low revs provided I keep a controlled step on the accelerator. It just dies when I let off the gas pedal completely. In any case I’ll do some more testing and see what comes up.

I’m just afraid that if I tighten the throttle cable to simulate that light step to keep the idle, it might be just a temporary fix.

[Julius Platon]

This is the statement I was looking for.

“(throttle cable is never used to adjust idle)”

I pulled it from another forum.
http://www.hondaaccordforum.com/forum/diy-answers-28/setting-base-idle-speed-38734/

So I’m guessing there’s something else wrong with my car and it isn’t the throttle cable at all.

[Julius Platon]

I’ve got this carburetor that sits up top the intake manifold, the kind that uses a pan to hold the ring filters. It makes adjustments mighty difficult when the pan is on there. Does anyone know what model carburetor this is? Anyhow I did some fiddling with the idle speed screw (circled in green) and the car began to idle nicely for about 10 minutes or so. I also noticed the vacuum actuator circled in brown move backward loosening the adjustment. Does anyone know what this is called and when or what conditions are met before it moves the idle speed adjustment screw back and forth? There seem to be no harm done to the idle at that point.

When I began to put the pan filter holder back on and connected the vacuum hose to it (circled in red) and tightened everything down it bogged down and died. I can actually get her to idle by adjusting the screw (circled in green) but it wasn’t as smooth as before. I can hear a hissing sound and my friend told me it’s coming from the break booster, but I can’t be too sure. A mechanic told me it’s the coolant in the AC thats equalizing the pressure, but I have my doubts.

Still searching around for a leak. But it seems my hoses might be shot.

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