black stuff coming out my exhaust? oil?

[maccona35]

hey, i have a vl exec and have started running it on optimax the last 5 or so weeks. The lat week or so the car has been running really ruff. ie it feels like its about to stall all the time then the engine clicks over again and so on... Yesterday i noticed black smoke coming out the exhaust so i went and checked it out and my jumper got covered in black dots which i think will be oil. What does this mean? Should i stop running it on optimax? i heard it was better for you car so ive been running it on it. How can it be fixed? How much do you think it will cost ruffly

maccona

[ucwepn]

black smoke usually means its running rich. Is it using allot of fuel? Blue smoke usually means piston rings, white smoke is usually head or head gasket. It is probably unburnt fuel coming out of your exhast, the travelling down the pipe will blacken it. Go and get your timing checked and AFM and O2 sensor and coolant temperature sensor. (all these things can make it run rich.)

[rb26dett]

Sounds like it is running too rich.

[maccona35]

so should i not use optimax anymore?

[vlct400]

its running rich try pullin ya plugs out and clean them it should run better again my turbo is doin it cause the computer is stuffed so yer try that

[ucwepn]

the optimax shouldn't cause any harmful effects, Although using 20 years of regular unleaded and then switching to premium will clean all the carbon deposits out of the fuel system and combustion chambers, so it may just be deposits getting cleaned out. I have heard bad things about shell optimax, They say that its just regular with LPG pumped through it to give a higher octane rating. Try one of the other companies for a while, Vortex is good and has a very good reputation same as mobil 8000 or whatever its called.

[maccona35]

has anyone else heard that about optimax?

[ucwepn]

I read it on a thread on this forum somewhere from someone in the industry.

[rb26dett]

You might just need to give it a bit of a flogging to losen up the carbon deposits.

[maccona35]

do you think thats why its running really ruff because its trying to loosen up all the carbon deposits in the engine?

maccona

[HSVenforcer]

the optimax shouldn't cause any harmful effects, Although using 20 years of regular unleaded and then switching to premium will clean all the carbon deposits out of the fuel system and combustion chambers, so it may just be deposits getting cleaned out. I have heard bad things about shell optimax, They say that its just regular with LPG pumped through it to give a higher octane rating. Try one of the other companies for a while, Vortex is good and has a very good reputation same as mobil 8000 or whatever its called.

not following how the LPG can be pumped through it. Do you mean the LPG is disolved into the liquid like CO2 gets disolved into fizzy drinks? if so then surely it would eventually remove itself?

[HSVenforcer]

My first thoughts are check plugs, emissions sensor and water temp sensor. Failing that remove the injector connectors one by one to see how that affects the idle. Check that the hose on top of the rocker cover (cant remember what its called) is secure at both ends and not split. Check the distributer and rotor button.

I guess a compression test would be the next logical idea.

[ucwepn]

not following how the LPG can be pumped through it. Do you mean the LPG is disolved into the liquid like CO2 gets disolved into fizzy drinks? if so then surely it would eventually remove itself?

Yeah just like you said, Fuel these days only lasts for a couple of months before it starts to go stale, I have heard stories of optimax going bad after less than a month so this could very well be the case. I wont use shell personally, heard too many bad stories. Some of the independants are not the best either.

There is a thread here about premium unleaded I'll try and find it later.

[vlct400]

hey bax i like the sound of givin it a floggin i like doin that

[vlct400]

my turbo runs really bad on BP ultimate and great on that freedome stuff with the ethonole in it

[thestash_16]

dude you may have a blown head gasket.....they arent too hard to fix. you'll also be able to clean out your piston chambers and rings!!!!! also check if anything around or in line with the head gasket area is covered in oil. if there is........bye bye head gasket!!!!!als listen for a constant tapping sound....if there is.u need a new head gasket!!!! the smoke means that oil is being burnt.(mayby)

[ucwepn]

Constant tapping sound is usually the lfters all gunked up or worn, or 1 or more broken exhaust manifold studs. To check for a blown headgasket you look under the oil filling cap and see if there is any white stuff there. and remove the radiator cap with the engine running (be careful) and check for tiny bubbles coming to the surface.

[maccona35]

thanks guys , ive taken it to the mechanic he can figure it out im not to good on cars lol. ill let you no the outcome
cheers
maccona

[Henerz]

so what was it maccona?

[vn88calais]

certain exhausts use more fuel and some spit out a bit i know that, not sure if thats the prob...dunno hope it all gets sorted dude

cheers, Todd

[Tree cutter]

Black smoke means that it is running rich which has probably fouled your spark plugs up which would make it run rough. At a guess i would say that your oxygen sensor is stuffed. Optimax is a thinner fuel than regular unleaded so more fuel will run into your engine causing it to run rich which your oxygen sensor should sense and cut back the amount of fuel going into your engine. The problem you are having normally happens on engines that have a carby or a fully mapped injection system.

[Bax]

Black stuff - usually water mixed with carbon, smells like fuel but it isn't. Water is a bi-producut of the combustion process.

Maybe that your running slightly rich though.

[maccona35]

hey guys, yeh i took it back to the mechanic i brought the car off and he said the car never been run on optimax, the black stuff was all the carbon getting cleaned out. The car as been running smooth as for about 2 weeks now so i think the engine is getting use to the better fuel.

cheers
maccona

[Henerz]

yeh I was waiting for your reply...cuz similar situation happened with my car, I've been runnin on Optimax since January.

[abcent]

i'd guess the O2 sensor has had it and is making it run rich..

also, Optimax tends to do that a bit. I'm fairly new to these forums, having only just recently getting a VL for a daily driver, but have had experience on this in my skyine. The Optimax in my car had more of a strong fuel smell when running, and heaps of carbon deposits on the rear of my car (black dots). After having heaps of discussions about this with people I went and got the car dyno'd, it could only advance the timming a little compared to normal an it was running with more black smoke (rich) when on boost. i then used the tank till nearly empty an filled up with Mobil Synergy 8000 an had it retuned, I was able to advance the timming even more again, the fuel smell was gone, as were have the mess it made to the rear of my car, bonus also was more power.

Being a member of many forums around the place, the general consensis is:
from best to worst

1: BP ultimate
2: but just as good as 1: Mobil Synergy 8000
3: Shell Optimax and Caltex Vortex