Red exhaust soot

[TJ 450]

Now that my 6.9 runs a bit rich at a cold start, I've noticed red soot marks all over the driveway.

I'm quite certain that it's from an octane booster that I used a while back, but I'm surprised that after a few visits to the servo and hundreds of kms it's still red!

I guess this is a bit of an FYI for the use of octane boosters too.

Tim

[plmstr92]

Possibly an additive thats already in the fuel when you buy it? , as we all know that the fuel companies throw in other chemicals to avoid large tax bills.Toluene i believe is one of the most common 'duty free' additives which helps the garage owner make his fortune.

If i remember that at one time 50% of the fuel in your tank would of been toluene and not petrol.

Just a thought.

[TJ 450]

A bit of research shows that it may be MMT, which is used as an additive in fuels, and octane boosters.

http://en.wikipedia.org/wiki/Methylcyclopentadienyl_manganese_tricarbonyl

It may be due to the fact that I attended a different service station than usual. Good thing the car doesn't have catalytic converters and O2 sensors, because they would be ruined.

Tim

[Big_Richard]

what fuel are you using ?

I only ever put bp ultimate in my car and it has no red soot.

[TJ 450]

I went to a Caltex/Woolworths outlet, and filled up with Vortex 98. Red soot was noticed immediately thereafter, but I had experienced it before only with the octane booster some months ago.

The evidence is there on the driveway. The previous time I started the car, the soot was jet black, now it is red. I think I'll be going to "bp" next time.

I'll probably lean out the mixture slightly too.

Tim

[thysonsacclaim]

MMT and MTBE are both common additives and the companies also (here anyway) add detergents, esp to the higher octane rating gasolines, right before the fuel is shipped off the the station.

Most of the regular products added to gasoline (toluene, acetone, ethanol, xylene, iso-octane) tend to burn 'clean.' They usually burn to leave little to no residue (except if you're talking about diesel). Any soot formed is usually from incomplete combustion or because one or more products has released carbonization from the engine by acting as a solvent. You can get this from changing gasolines types or after adding a cleaner. Things like Pouring Seafoam down the intake results in a huge amount of carbon being broken up and pushed out the exhaust.

One interesting thing, though, is that some fuel is dyed red. In the US, we use red dye to indicate high sulfur diesel. The dye is to distinguish duty-free fuel or fuel meant only for off road use (farming, etc). The fuel is less refined, so it's cheaper for farmers to use this type of fuel, but highly illegal to use in a regular car. Maybe the station owner was trying to get by cheap? Although, I'm not sure if they dye off road gasoline red there or not.

I would put my money on that it is probably something like ferrocene, or iron pentacarbonyl added to fuel. Both have iron in them, which generally leaves black or red deposits (like red [iron III oxide] and black [iron II oxide] rust). MMT has no iron in it, so I don't see how the red would come unless it's breaking apart rust in the exhaust. MMT has manganese, which typically would leave silvery or white deposits.

Very strange.


EDIT:

Ah looky here: http://en.wikipedia.org/wiki/Ferrocene

Ferrocene and its derivatives are antiknock agents used in the fuel for petrol engines; they are safer than tetraethyllead, previously used.[30] It is possible to buy at Halfords in the UK, a petrol additive solution which contains ferrocene which can be added to unleaded petrol to enable it to be used in vintage cars which were designed to run on leaded petrol.[31] The iron containing deposits formed from ferrocene can form a conductive coating on the spark plug surfaces.

In diesel-fuelled engines, ferrocene reduces the production of soot. Ferrocene is available under multiple brand names, including Ferox.

[oscar]

Sure it's not rust?  A bit too obvious but worth a mention.

The 350 runs rich and spits out water droplets when it's warming up.  It'll throw out little black droplets but before I had the centre resonator replaced it would throw out some rusty droplets too. 3km to work and back in winter without allowing the exhaust to warm was the cause I reckon.

[thysonsacclaim]

Sure it's not rust?  A bit too obvious but worth a mention.

Could be? It could also be that whatever is in the gas right now is helping to free up rust that was previously stuck in the exhaust system.

[TJ 450]

That all sounds pretty reasonable to me... although I hope it's not rust from the exhaust system beyond the manifold, as it's only about a year old, and I well and truly warm up the car with almost every drive.

The first time I ever saw the colour change was with the octane booster, not again with the previous fuel now it's black again. Weird.

Anyway, I'll keep an eye on it and do something about the CIS, as there's a nice  cloud of black smoke out the exhaust when I start her up now... clearly the WUR is set up to allow a lot of cold start enrichment.

Anyway, my plan was always to get the original WUR refurbished and refit the old fuel distributor.

Tim

[thysonsacclaim]

It's interesting because before joining the forum, I never realized the importance of warming up the car to ensure oil gets around and condensation heated out. It's pretty humid where I live, so after a while I did start to notice the milkiness that accumulates under the oil fill cap from condensation. Never noticed it on other cars I owned, though not sure if they would have had the problem being much newer vehicles?

I'd certainly hope it's not your exhaust as that would just suck being that you just replaced it.

Out of curiosity, which additive did you use? I'm just wondering for personal reasons about ingredients and also because I don't know what they sell over there in Oz. I work in the petrol industry, but I'm only vaguely familiar with how things are done in places outside the US (eg RON rating versus AKI, etc) since I've only ever been placed in the USA.