infinitypro12

Ok, so I have a 96 running a B18c1 Engine and matching transmission, the exhause is an APEXi N1 (I didn't put it on and am in the process of taking it off), and there has always been black build up on the rear bumper and part of the trunk which easily comes off when washed but due to the fact that I bought the car with the muffler some of it is caked into the paint.

I have been researching for sometime now to figure out why this build up keeps coming back and a few major concerns come up.

1. The biggest is that my piston rings are fried causing burnt oil to exit the exhause manifold and down the the pipe and creeping out the bigg a$$ end of the N1 due to lack of back pressure. But I could have sworn that if your piston rings are completely shot it will make some kind of aweful noise or not work right at all and my engine and tranny seem to run fine.

2. Another concern is that the build up is coming from the piping of the exhaust system itself and decomposing internally. Externally, it looks fine...

3. Last, my car seems to run a little rich which I feel is due to the lack of back pressure to provide and accurate reading from the O2 sensor causeing improper engine management and things to wither away in that sense.

Other that those I am with out a clue and will welcome anything or personal experience. If my rings are fried, how intensive is that? Is it worth it? I'd hate to assume worse case scenario but I have to as this is my daily.

Anyway, thanks.

98civdx

blow by.
happend to my accord all the time. later found out the rings werent sealling properly.

has the car been proprely tuned?. run a compression check and come back with the numbers. rings can be farely simple, the biggest thing is you will need to hone the block, and totaly tear it down, but this gives you a give time to replace some internals that you wouldnt have normally thought about.

93HondaDelSolSi

i would go with what civdx is saying. run a compression check and maybe a leak down test if you have access to a leak down tester.

z6htch

Agreed ^ but why would you wanna get rid of the N1 if its a real one. I have one and love it

infinitypro12

The N1 is so loud above 55 mph and I just don't like that kind of attention. I'll have to do a compression check but I really don't want to do a tear down. Correct me if I am wrong but shouldn't there be some noticeable performance and engine smoothness decrease if the rings are shot. Most of the tuning shops around here have bad reps and I usually have little time to figure it out...one hell of a pickle I'd say. I'm not car illiterate but I don't mess with things I don't completely know how to do, ha ha.

Compression test it is.

Again, my car is running rich and according to some searching it may be a faulty exhaust system build...see http://www.preludezone.com/exterior/...-deposits.html. So there's that.

infinitypro12

Pretty sure it is just running too rich which isn't good but better than running lean. Once again no one to attest to actually having this issue.

deadazleep

i have a b16 hatch and mine slowly gets the black build up, not dark and not spotty. Just looks like a fine mist of black oversprayed around the muffler and rear of car. I'm pretty sure its due to the previous owner putting in a super cool mugen knock off chip on a stock motor (/sarcasm) causing it to run rich. Ordered a stock basemap from phearable.net and hoping that will clear things up.

Former User

OP: Are you burning oil (blue smoke) or getting very bad gas mileage and running rich (black smoke), or both?

98civdx

if your rings were shot you would burn oil, buddy burned 3 quarts a week, and you could clearly tell it was loosing power.

take it in a have it tuned if its runing rich.

Koopa Troopa

A lot of the problems with carbon build up on bumpers is a simple solution of the exhaust tip itself not clearing the bumper. Is it a stock engine and ECU?

As far as your car running rich because of a larger exhaust? That's nonsense, if anything it'll run leaner due to the MAP sensor not adjusting for the added airflow.

The_Honda_Guy

Most likely you're burning oil. My 94 EX with 200,000 miles has blown valve stem seals causing it to burn oil and the back bumper has the same spotty sooty blackness to it. Unburned fuel won't stick to your bumper like burnt oil does.

infinitypro12

I'm not burning that much, maybe 1 quart since late July.

I do think that there isn't enough pressure to clear the bumper and at idle it just sort of dribbles out.

Sounds like I'll just have to run a compression check. Car seems to get decent gas mileage with the average around 29 to 30 mpg but that's between city, town, and the occasional vtec pulling on to the highway and I'd like to state that is rare but why have it if your not going to use it. Then again, I've had newly rebuilt motors that burned oil and I feel at this point it might be cause for concern but not an immediate tear down. I am concerned with the winter months coming and I hate doing car work when it's 28 outside.

I am running a b18c1 and I believe the ECU is out of the matching car, GSR. I absolutely hate the n1 ha ha bad noise during trips but from what I have seen on other cars with the bigger cat backs and no extra pressure they have black build up too.


Thanks again for everyone's insight and I was really worried for a little but if worse comes to worse then I have an excuse to upgrade or build something that I know I did instead of guessing.