My cousin has a 1990 Civic with a B18A1 engine and trans. The problem he's having is that as he's braking, coming to a stop and the car is put into neutral the engines RPM's will drop below 500 RPM and the car will stall. It doesn't have any problems with the idle speed which is at 700-750 RPM and steady. It only happens when he's coming to a stop and puts the car in neutral. The RPM's won't catch and stay above 500 RPM's.

He took it to the dealership and they said that it was his timing and adjsuted the timing for him. It ran ok for about a day and then the problem is back. Does anyobdy have any ideas on what the possible cause may be or did anyone have this problem before?




Modified by ITR420 at 5:54 PM 4/12/2003

 

When I had a problem like this it turned out to be the fuel cutoff solenoid, but mine's a 3bbl- unlike our cousin's. Eventually it got worse so that it wouldn't idle normally at all.

 

Hmm, it could be the brake booster hose on the intake manifold.

When you brake, the brake booster sucks vacuum pressure from the intake manifold, and while in neutral, you may have a small leak in the hose.

What happens when he brakes while in gear?

 

The car is fine when you brake in gear. The problem occurs when he is coming to a stop and lets off the gas when the RPM's are already low. The RPM's will drop below 500 and the car will stall even if the car is still rolling. Under normal conditions when you left off the gas the RPM's drop to your idle speed and maintain a steady idle correct? And his drop below his idle speed and stalls. It's not all the time, but more than enough to be very frustrating.

 

I just checked his vacuum hoses and everything is connected and there are no leaks. The car has a somewhat irratic idle now and seems to be very low in the 300-500 RPM range when at normal operating temperature. We checked the plugs they look fine, the timing is right on the money and a compression test shows everything looks good as well. But the damn things idles for ****. How can I tell if it the Idle Air Control Valve acting up?

 

is it supposed to die when he brakes in gear?

ive noticed when i'm at a complete stop in nuetral and if i stomp the brakes, my idle changes. it goes down a little (while the booster is using vacuum) and then it jumps up to about 1000. then it goes back to about 600

 

Check all your vacuum lines going in and out of the intake manifold. Also, your throttle body and intake manifold gasket.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by poison &raquo;</TD></TR><TR><TD CLASS="quote">Hmm, it could be the brake booster hose on the intake manifold.

When you brake, the brake booster sucks vacuum pressure from the intake manifold, and while in neutral, you may have a small leak in the hose.

What happens when he brakes while in gear?</TD></TR></TABLE>

I think it is what poison said. I had the exact same problem with my '76 Civic and that's what it turned out to be.

 

Check the IAC(Intake Air Control) Valve. My car would stall everytime I'd throw it into neutral, alot of HT members told me to check that. My problem ended up going away before I could check out the IACV. It's located on the bottom of the throttle body. Hope this is of some help-Dan

 

Adjust the idle screw on the Throttle Body, burp the water system (by taking off the cap when engine is cold, let it warm up and all the air bubbles come out of the system).

Also clean your IACV. Simply take it off, and put either Brake cleaner, Carb cleaner or Throttle body cleaner on the IACV and the port where it goes on the Intake Manifold.

Edit -- BTW, depending on the manifold you have. On B and D series, the IACV is on the back of the Intake Manifold. On H and F series, they are on the front.

The sensor Dsayavan states is the fast idle which a coolant line goes thru. There is a rubber piece on it, and a screw inside of that. Make sure that is tight as well.

HTH