so I recently purchased a 93 civic dx at 207 km to get me around yada yada first car got it for cheap. it's been great for about 5 days but as of recently it can have a rough idle also as if it's about to stall. To try and get it out of that feeling I rev up the engine a bit and white smoke comes out. My friend fears that it's coolant burning. As soon as I get the car going it's all fine back to normal. All spark plugs were recently replaced, a semi used rad was installed(not by me though...) to replaced the old broken one. No over heating, no check engine lights, coolant isn't at a loss.

All this happens after I have driven the car with a little acceleration then normal. I'm a little anxious to know if it has to do with a soon to be gone head gasket or a cracked one or something else. The car is going in for cert, but I'll definitly have the fam mechanic look at the situation. I'm willing to put into it, only if I can get a good amount out of the car, know what I mean. I've been searching for other people with problems like this, but it seems it's not as bad(over heating, white smoke from engine etc) as what my problem is. Does anyone have any suggestions as to what else it could be? thanks in advance for your opinions.

 

I would also like to note after the car has been sitting for a while it starts up fine and then idles normally. this is very weird to me.

 

white smoke is a sign of burning coolant - doesn't need much to do it - the headgasket could be leaking and not completely blown

 

Aight, obviously the problem is when the car isn't at SOT (standard operating temperature)... It doesn't do it when ur engine is warmed up, and if it's been sitting for a short while or so it doesn't do it (takes about 2-3 hours believe it or not for a car to completely cool down after reaching SOT as the water's approximately 90ºC/200ºF)... So you can rule out the new radiator... (radiator's not in use while car is warming up)... It sounds like ur IACV (Idle air control valve) but then u'd most likely be throwing a CEL, also it could be ur TPS (throttle positioning sensor), but then again, u'd most likely be throwing a CEL.....Blah, might be a problem with the fuel system but it's probably integrated with the smoking problem..

Do a compression test, that'll tell ya if the rings are good..the smoke doesn't look blue u said so I doubt it's the rings...and if the headgasket's shot u'll be smoking like crazy (whitish - clear)..but even if it's just leaking it'll smoke... Change ur headgasket, and see where you are from there...if that's not the problem make sure ur fuel pump/filter is alright, it almost sounds like it's not priming enough..but that wouldn't explain the pump (and I'm pretty sure they're connected)..

Change the headgasket, then let us know where u r from there...