All,

I have a 2001 Accord EX, 2.3l with 5 speed manual tranny. Recently, when approaching a stop and applying (pressing down) the clutch pedal, the engine stalls. It does not doing at every stop, however. It is becoming more frequent though. I can't seem to identify any particular pattern for when it does happen.

Thus far I have cleaned the IAC valve, which had a good deal of carbon on it. I have also cleaned the throttle body. The engine idles just slightly above the second hash mark from zero on the tach. I'm guessing that this is about 650.

When this occurs, I get no 'check engine' light that comes on indicating a fault; I simply turn the key and it starts right up again.

Does anyone have any suggestions as to what's causing this issue? Is it possible that the IAC is going bad?

Thanks,

Anthony

 

Is it only when holding down the clutch pedal? or will it stall if you put the clutch in, put it in neutral, and let the clutch back out?

It does sound like an idle-related issue to me though...

 

Hi,

Thanks for the prompt reply. The stalling occurs only when I press down on the clutch. So for example, if I'm approaching a red light, I typically press the clutch in, put the shifter in neutral, then coast to the light. Then, when stopped, if I attempt to press the clutch in in preparation to put the shifter in first gear, it stalls. It has also stalled on me when I press in clutch in while coasting slowly (as if I were preparing to put the car in gear and turn into my home driveway. It's very weird.

I'm guessing that maybe the IAC is going south but I'd hate to simply throw parts at it. Other than the stalling, the car runs flawlessly.

Thanks,

Anthony

 

Just another possibility to check... Hope this isn't it.

Say you're completely stopped, engine idling, transmission in neutral.
Set the handbrake & don't touch the foot brake.
Don't touch anything, especially the gas pedal.
Press down the clutch pedal.
Does it stall?

Next, try it again. Have someone press the clutch pedal while you watch the engine.
Watch the crankshaft pulley very closely, especially where it comes close to the little pointer for spark timing. Does the pulley move out from the engine a little bit?

That would be something wrong with the thrust bearing on the crankshaft. Unfortunately it's a big job to get there...

Another possibility would be a problem with the throw-out bearing at the clutch. Excessive drag in that bearing would drag down the engine RPM. But I have a hard time believing that would happen silently. I'd expect that bearing to make noises when you press the clutch pedal.

 

If I'm stopped at a light, engine idling, and I press down the clutch pedal, this is one of the two occasions where the engine does die. I want to stress though that it does not happen every time that I am stopped at a light. Sometimes, if I'm stopped at a light and I push down on the clutch, I can see the RPM's drop down slightly, say 50-100 rpm. Most of the time, however, the RPMs remain where they are.

I will check the movement of the crank vs the timing mark tonight and report back.

As for the throwout bearing, I would expect hear noises coming from it if it were going bad. But I hear nothing nor do I feel anything abnormal while pressing the clutch.

Thanks again for the suggestions!

Anthony

 

If it happens at a stoplight, be aware of what you're doing with the brake pedal. Stepping harder or letting off at the same time, a bad brake vacuum booster might introduce a sudden "vacuum leak" at the same time as you press the clutch pedal.

 

Hmmm, that's a good thought. Is there a particular process that can be followed to check for a faulty brake vacuum booster? Could there possible be any other symptoms associated with such an issue?

Thanks again,

Anthony

 

After turning off the engine you should still have vacuum-boost for your brakes, to press the brake pedal down a few times. When the vacuum is depleted, you'll feel the brake pedal get real hard & solid.

Try the same thing again. Except turn off the engine & leave it sit for say a 1/2 hour. Should not have lost the vacuum over that time, so it should behave the same way.

Another way to look at it... Idling in neutral, clutch engaged (NOT stepping on the clutch pedal). Don't touch the clutch at all, see if you can make the engine stall by playing with the brake pedal.

 

Hi JimBlake,

Quick update. This morning, I tried what you had suggested with the brake pedal. While sitting at a stoplight, clutch engaged (not pushed down), I repeatedly pressed and released the brake pedal. Wouldn't you know it, it died! Each time I tried this I got the same results - the engine stalled.

So, I'm guessing that I have a bad brake booster? Or maybe a leaking booster line?

Anthony

 

Excellent. That's a whole lot better than a bottom-end rebuild...

Look for leaking booster vacuum line first, that's an easier fix.
Or a bad check-valve in that line. That check-valve is supposed to be positioned with the arrow pointing away from the booster. Take the check-valve out, try to blow through it. You shouldn't be able to blow through opposite the arrow.

A good vacuum booster can cause problems like this if the push-rod from the brake pedal is adjusted wrong. I'd get a good shop manual for guidance on that. I know the general idea, but specific dimensions & adjustments should come from the book.

Have you tried to raise or lower the brake pedal? Have you replaced the brake master cylinder lately?