Dg331739

Ok, i've done lots of searching, but im new here. this seems like the only forum that actually has members with useful knowledge and a zest for helpfulness. . .

I recently purchased a 94 civic hatch DX from my cousin. . for 500.00 car runs great, for the most part. .

but i have noticed that when the car gets to running temperature, the idle starts to seek, and it smokes pretty bad. . its very white smoke, and smells like its running rich. .

i've already followed the ***clean your iacv*** thread, and it didnt help. i've also read that a clogged cat could cause the smoking, but it doesnt explain the idle. its got a new head, and head gasket. that were put on before i got the car.

she's not throwing any CEL's, cranks, turns over fine, even when warm. which from my understanding doesnt correlate with a faulty IACV either.

im a piston noob per se. . . the only car i owned that i did work on personally was my rx8 that i destroyed in july. . im at a loss. . any help would be great. Thanks.

grumblemarc

iTrader: (4)

Rings are shot. That's what you get for buying $500 cars.

skill178

rings would be oil smoke, always seen oil burn blue. white is typically water aka blown headgasket.

why was the gasket replaced? was it blown previously. if so the new one might not have been done correctly or the head might be warped making it not seal off.

does the cooling system seem to be losing water or have excess pressure build up? also is there any water in the oil or oil in the water?

skill178

Blue/Gray Smoke: Blue/gray exhaust smoke is an indication of oil burning in the combustion chamber. These are possible symptoms and causes:

Valve Seals: Leaking valve seals will cause blue/gray smoke at startup because oil leaks past the seals into the cylinder after the engine shut down.

Valve Guides: Excessive clearance between the valve stem and the valve guide allows oil to leak past the gap into the cylinder.

Piston Rings: Worn or damaged piston rings will cause blow-by resulting in blue/gray smoke.

Worn Cylinder Walls: Worn cylinder walls cause blow-by resulting in blue/gray smoke.

PCV System: A stuck closed PCV valve will cause excessive crankcase pressure resulting in blue/gray smoke.

Black Smoke: Black exhaust smoke is an indication of rich fuel condition. These are possible causes:

Fuel Injectors: A leaking or dripping fuel injector will cause a rich fuel condition.

Fuel Pressure Regulator: A stuck closed fuel pressure regulator will cause a rich fuel condition.

Fuel Return: A restricted fuel return line will cause a rich fuel condition.

White/Gray Smoke: White exhaust smoke is an indication that coolant is burning in the combustion chamber. These are possible causes:

Cylinder Head: A crack in the cylinder head (around the coolant jacket) will cause coolant to enter the combustion chamber.

Engine Block: A crack in the deck of an engine block near the coolant jacket will cause coolant to enter the combustion chamber.

Head Gasket: A damaged or blown head gasket will cause coolant to enter the combustion chamber resulting in white/gray smoke coming from the tailpipe.


-credit http://www.freeasestudyguides.com/exhaust-color.html

Dg331739

The gasket was replaced because they rebuilt the head on it. why the head was rebuilt i have no clue. oil seems clean and the water is ok. it looks a little rusty, but with an original radiator thats to be expected i guess. the smoke is white, thick white.


i originally suspected head gasket, on the smoke issue, but the oil isn't contaminated. (milky, foamy - chocolate milky in color)

skill178

sounds like water. was the gasket/rebuild done at home? not saying its true but theres a good possibility it was done poorly or incorrectly.

something as simple as removing the head bolts in the incorrect order or installing the in the incorrect order/ torque steps could cause damage to the head and make it not seal correctly.

by the way, a correct anti freeze/water mixture will prevent rusting.

Dg331739

it was done by his highschool almost a year ago, in their shop class, under the supervision of the instructor. but thats no guarantee i guess. thanks for the feed back, i guess im replacing a head gasket.

skill178

if that high school instructor is anything like mine I would trust it to be correct, but saying that I would NOT trust my college's shop instructor...

sad isn't it?

as far as you are aware the engine has not been ran hot has it? that's a death sentence for a aluminum motor.

if you do replace it make sure to get a metal one and not one of the **** composite material ones.

Dg331739

i dont believe it was run hot, but in saying that it very well could have been because i noticed the cooling fan doesnt work. -_- so much for a "good buy"

skill178

the fan don't mean too much, ive ran my 91 Si for over a year without a fan. it can idle for hours on end with the heat on and it wont go past 3 O'clock on the temp gauge.

also has a full EF radiator though as long as it don't get stuck in traffic for prolonged times the fan wont do to much.

Dg331739

ok, then im not worried about that, it doesnt seem to get hot either. . what do you think about the idle issue ?

skill178

what exactly does it do? does the idle fluctuate randomly? or does it jump in a continuous manor?

ive seen blown head gaskets make cars not idle for **** due to water in the chamber.

Dg331739

its a consistent, and constant raise and drop in rpm. rythmic, and it stops when i rev the engine, once it hits idle rpm again, it resumes. . . it doesnt do it when cold. only at running temps.

strategy400

It's probably the rings or the headgasket not sealing properly because the block was not decked/resurfaced properly. Honda has a specification for the surface finish of the deck for a reason. Putting a headgasket in without a proper surface finish is like putting rings in without honing. It might seal, but more than likely not. Also the difference between the metals in the block and cylinder sleeves will cause differences in the heights over hundreds or thousands of heat and cooling cycles. The deck will develop defects at critical sealing points on the tops of the cylinder sleeves that are difficult to detect with a precision straightedge. Slapping a resurfaced head on an old V8 had a good likelyhood of success but with the design of these Honda blocks, it's hit or miss, and often a miss as evidenced on this very forum.

Notice the defects on these blocks that might have caused a sealing problem:

Dg331739

so i need to get my block resurfaced. . . where the H*#* does one get that done? and how? and how much?

strategy400

This would be done as part of a rebuild if your engine has high mileage. A quality rebuild with good cores is about ~$1300-1700 at a union shop.
Also, I would definitely do more investigation and diagnosis before jumping to the conclusion that you need a rebuild. Leakdown, compression test, block test, cooling system pressure test etc. etc.
The thing that makes me suspect a headgasket and/or block issues is, it was already replaced for some reason.
Then again, it could just be the rings in which case you can maybe live with a little smoke while you save for a rebuild/swap/new car.