O/T - Honda Integra Overfuelling?
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Off topic guys.

A mate of mine has a japanese spec Honda DC2 Integra. Over the past couple of months, it's been spitting black residue out of the exhaust all over the rear bumper, when at full chat there has been some puffs of black smoke which smells like something burnt, cant really describe it.

Anyway, he spoke to a Honda specialist, who pointed him in the direction of a worn rear engine mount causing the issue. The mount needed replacing as it was badly worn, the idea was that with the mount shot, under alot of pedal the engine twists back with the torque, opening a gap in the knuckle joint at the end of the manifold. This joint being BEFORE the O2 sensor.

So we felt quite confident that this was the cause, the O2 sensor telling the ECU to chuck more fuel into the mix.

We changed the O2 sensor (with a known working one), while we were at it, and replaced the rear engine mount. The engine is now solid, initially it did smoke under heavy acceleration, we put this down to perhaps exhaust paste/condensation being spat out of the exhaust? We also re-set the ECU.

Anyway, I got a phone call earlier from him and he's said its started to smoke abit again (black-ish in colour), under heavy load, but doesnt smell as much anymore.

What other things could cause this guys? I was thinking that seeing as its been overfuelling this whole time, theres alot of coke and crap in the exhaust system that would take a while to clear?

Sorry for the long winded off topic post, just thought i'd see if you chaps had any clues or pointers as to what it might be?

Cheers

Rich

Edited by richminiturbo. on 13th Jun, 2009.

do they run a twin sensor on the integra's? also what fuel is he using in it? not sure if it would happen but it could be overfueling as its running a lower octane than the ecu is used to (jap inport)

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Twin O2 sensor you mean? If so, i'm 90% sure they dont. Where would a second one be, after the cat?

He has alway run it on optimax/v-power. It's been in the UK for quite a while now and it ran sweet as a nut when he bought it. Still does, just smokes.

He's getting worried it's his head gasket, but I would have thought it would have started running like a dog by now? It's not using loads of oil or water, so I cant see it being a headgasket related problemo?

Edited by richminiturbo. on 4th Jun, 2009.

The ECU doesnt know the octane rating of the fuel being put in the tank, so it wouldnt be adjusting the fueling to deal with this.

What mods are on it?

How much black smoke? little puffs?

How many miles on the clock?

60k on the clock.

The black puffs are at high revs, id say a little after VTEC and ends on gearchanges.

De catted?

AlexF

Nope its got a cat and the mecanic mentioned this was in tip top condition.

they do run pretty rich up top tbo, and isnt uncommon for them to burn a bit of oil at full chat right up the rev's. do a leak down test :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Valves or blow-by. High mileage B18 motors were notorious for burning oil, and spitting out black crap.

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Hondas do run quite rich towards the redline standard, how many miles has the Cap/Rotor arm plugs done, as they could be worn causing a slight missfire up the top end which you may not feel. as above the B18s do tend to get a little oil thirsty after higer millages, the obvious sign of this is checking hte dipstick regularly, etc.

the ECU will only learn while in closed loop/part throttle so if the lambda sensor is giving lean readings and the ecu is trimming due to this is will hold this compensation for when it goes into open loop/wot and be rich.

West

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my high compression mpi does this.

going for a full engine rebuild.

Sorry guys I didnt realise there had been more replys!!

Bit of an update really, I've just been round his house and we decided to check + clean the airflow meter. I'm glad we took it off as the inlet side of the throttle and the whole of the plenum was FULL of thick sticky and wet black residue. Its hard to describe the smell but it doesnt really smell like fuel or oil but its got to be one of the two right?

Anyway, he sprayed a load of carb cleaner into the plenum to clear it out. Hasnt had time to drive it but im confident this will stop the black crap at full throttle!! Seeing as when the car was idleing on restart there was a little ploom of smoke that smelt like carb cleaner coming out of the exhaust.

My immediate thought was something to do with the breather system, what do you reckon guys?

I thought blow-by too, but blow by wouldnt go past the inlet valves and back up into the plenuiniarm would it?

Edited by richminiturbo. on 13th Jun, 2009.

no but it pressurises the crankcase forcing oil out the breathers into the plenuiniarm :)

Edited by evolotion on 13th Jun, 2009.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

But surely blow by would cause running issues? What with compression being lower wouldnt it be noticeable even if on one cyl?

no no runnign issues, will just simply have blow by / burn oil at high rev's they all do it onc ethe mileage starts to get up, its a common thing, either keep the oil level checked or rebuild :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Cool cheers Denis :)