CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Can someone do the "Uncle" thing for me and tell me what's up?

My 85 honda civic keeps stalling out, especially before turns or from stops, and now it has started to continue turning over after I shut it off, but really rough, like shaking the car rough. Maybe if I have some idea what I’m talking about when I get it to the shop they won’t treat me like a complete moron…

If you open the hood, and look on the passenger side of the fire wall, you’ll find a black plastic box with a lot of numbered vacuum hoses going to it. Make sure none of these hoses are leaking. If none are leaking, then one of the solenoids inside the black box for the feed-back carburator control system might be malfunctioning.

Tester

The engine may be “dieseling”, which means that red-hot pieces of carbon in the cylinders are continuing to ignite gasoline in the cylinders after the ignition is shut off. When this takes place, the engine runs VERY roughly and you will smell really foul exhaust fumes. You can stop the engine from doing this by moving the the shift lever back to the “Drive” position in order to stall the engine.

The solution may involve simply retarding the ignition timing (assuming that it is adjustable), or it may require “decarbonizing” the engine, or both.

I’ll check the hoses in the morning. Just now, it was idling real high, would that be consistent with the hose leak?

Are either of these procedures very expensive, or could they be done by a skilled non-professional? I’m a disabled vet, and might be able to find someone in my Legion who could help if it is relatively simple.

Since I don’t know the skill levels of these people at the Legion Hall, it is not really possible to give you a definitive answer. However, someone who was used to doing tune-ups on his cars in “the old days” should be able to adjust the timing (assuming that it is adjustable on this car).

Additionally, this car may need some basic maintenance (spark plugs, air filter, fuel filter, etc.) in order to get it running properly. Is all of the maintenance up to date?

If the engine needs to be decarbonized, that may require specific experience with this procedure.

Incidentally, if the idle speed is too high, that is also something that can contribute to dieseling.

Here’s my guess, consistant with what’s already been posted.

The engine has been running poorly for some time now, allowing carbon deposition in the cylinders, possible on the plugs. If you’ve even had a charcoal bar-b-que you know that carbon retains heat.

The engine operates by drawing air and fuel into the cylinders with each intake stroke of a piston. The mix is then compressed and heat energy is added by the spark plug, triggering combustion.

In your case, when you turn off the key the cylinders are still pulling fuel from the float bowl, pulling air from somewhere, and you have enough heat retained in the carbon in a few of the cylinders for the combustion process to continue. So eth engine keeps running even without the spark plugs firing, at least until the float bowl level drops. What I’m wondering is how it’s getting enough air. The throttle plate should be closing completely to choke off the engine and prevent this. In the old days “idle stop solenoids” were used to control this, but I don’t know how an '85 Civic does this.

VDC is right. You have a myriad of problems all operating together. Someone needs to take a good overall look at the engine and carb. It’s long overdue some maintenance.

Fuel filters last fall, air filter about due, spark plugs don’t know. As I’ve been living on my disability (almost entirely eaten up with rent/utilities) I’ve been just doing oil changes lately. I’m a farm girl, so I know this stuff needs doing, but have always had uncles to do the actual ‘doing’, except for oil changes, of course. They made me do them myself :slight_smile:

Alright, thanks. I’ll just have to quit driving it for a while until I have the money for someone to take a look at it. Rather what I was figuring, but thanks for giving me an idea of what I’m dealing with.