puckman1325

my 93 civic dx D15B7 is running bad when left at idle for a long period, and smokes white, but it will not run bad on a cold start and no white smoke. i first thouggt this to be a head gasket but it only smokes after 20 min of warm idle. suggestions please

ezone

If it isn't losing coolant, then chances are that it isn't a head gasket. Antifreeze smoke can smell sickeningly sweet too.

Oil should smoke blue or light blue (bluish), and hangs for quite a while in still air. Might be hard to tell the color if the light isn't just right. Compared to steam, it will be blue.
Condensation in the exhaust will steam out as the exhaust pipes get hot.

In general:
Smokes just a tiny puff on a cold start--valve stem seals, can be normal.
Smokes profusely after a cold start (like fogs out a city block) then stops rather suddenly--stuck oil rings.
Smoke after idling--valve stem seals.
Smokes after a deceleration (high manifold vacuum)--valve stem seals.
Smoke while driving and smokes worse the higher you rev up the engine--rings.

Any combination of those can make it hard to point at just one thing.

A catalytic converter can hide a LOT of oil smoke too.

Things like the PCV system adds an extra possible avenue for oil smoke, and varies with each engine design. Inspect, replace, or disable to remove it from the list of possibilities during inspecting/checking.

You don't have TOO MUCH oil in it, do you? Some lube jockeys think that all engines get 5 quarts, no matter if it needs it or not.

Wrong oil (too thick) could make it smoke or cause oil consumption too.

puckman1325

Thanks for the thorough response! I may have too much oil in it it is on the top hole on the dipstick, but would this cause the engine to run weird? and when it does run bad, i smell the exhaust and it has a very gassey smell to it.

-do these plugs look normal?

ezone

You mean the FULL mark on the oil dipstick? That means FULL. As long as it isn't like an inch over, that is fine.


Dumping a LOT of raw fuel into the exhaust without burning it- can make a bunch of really white smoke, but it almost would have to be physically dumped in, like if the engine was flooded and wouldn't start, with an hour of cranking it. That isn't your problem though.

That plug sure doesn't look like there's a problem with too much fuel or oil.
Was the engine shut off WHILE it was running bad and the plug pulled right then? If it was running good when the plug was pulled, the plug would only show that it was burning clean.

If it runs BAD, figure that out before worrying about any smoke.

Based ONLY on the plug I see there, a guess:
Could be lean making it run bad? Grab a spray can of something flammable (carb and throttle cleaner) and squirt a little into the throttle body when it's running bad, see if it straightens out for a little bit with extra fuel added like that. Don't just hose it in there, you'll flood it. Tiny squirts.
If it does run better like that, then start checking things that could make it run lean.....vacuum leaks, inaccurate CTS reading, low fuel pressure, etc.

iceblue civic

I have same engine d15b7 starts fine cold sometimes doesn't smoke im thinking head gasket cuz it does have sweet smell and smoke disappears quick dosnt linger and sometimes while driving it can be fine then bogs down what would cause that?