Blowing Out The Carbon?

My original question asking about miles was to see if the motor was shot with huge miles since he never posted this info originally. If the motor was toast further discussion would be moot. Its low miles which means there's a super rich issue.

Burning super rich tends to form carbon on the cyl head and piston as its poorly combusted.

Which is why I threw the Seafoam out there.

 

Its not for his Prius. The op asked about his wifes Solara in the first post.

 

I gotcha, Ed. I was merely trying to derail the issue of carbon when he is observing black smoke.Any carbon buildup in a low mileage vehicle is an indication of something else going wrong and not the root of the problem. If the car is running super rich then the catalytic converters are going to fail sooner than expected as well. This happened to my 2000 Trans Am within the first 20k miles (clogged cat).

 

I thought the Solara was just a reference point, and he was asking about taking care of the Prius, since this thread is in the GEN II PRIUS TECHNICAL DISCUSSION forum. Questions about other cars should be in one of the "Other Cars" forums.

When he asked "Should we periodically floor our cars...?" I thought he meant the Prius.

 

Yes!

 

I would take a look at the plugs before assuming anything more xomplex is going on. Something like a cracked plug can cause an incomplete burn and black smoke. Just because a given product may be rated for extended mileage or a data sheet may claim a long life does not make it so in real driving conditions.

 

It is all I use here in California, the regular grade. On another car my wife uses the highest grade Shell, smoothed her E320 MB car out nicely. I was surprised, and happy, because it had been idling pretty rough before.

 

Yes your are right. I did not fully read the post. Please accept my apology.

 

Never heard of Seafoam, so I Googled it.
Sounds like every body should have a can of it in the garage.
I take it, its possible use as discussed here would be for item #4 below:

Sea Foam Motor Treatment #’s SF-16 (16 ounce), SF-128 (gallon
container) and SF-55 (a 55 gallon drum) is used as a fuel additive in
Gasoline, Ethanol Blends, Gas/oil mixes & ALL Diesel fuels. This
includes all brands and grades of available fuels.
When added to these
fuels, Sea Foam Motor Treatment was specifically designed to safely do
five (5) important tasks for you. They are:

1. Lubricates upper cylinders, fuel pumps, turbochargers, drawn-
through superchargers, and related fuel system and exhaust system
components. Sea Foam Motor Treatment is a 100% blended petroleum
product. That means Sea Foam is OIL, so adding Sea Foam to ANY fuel
adds lubricity to fuel system components and upper cylinder areas of
your engine.

2. Dries fuel system moisture. Sea Foam Motor Treatment contains an
oil component that acts as a co-solvent to effectively neutralize
moisture when Sea Foam Motor Treatment is added to any of the
above-listed fuels. This helps to eliminate moisture-related problems
like diesel fuel gelling and rough idling.

3. Cleans gum & varnish fuel residues from fuel system components.
Sea Foam Motor Treatment contains an oil-based high-detergent
cleaner that liquefies old fuel residue and allows the contaminants to be
filtered out in the manner designed by the engine manufacturer.

4. Cleans carbon deposits from combustion chamber. Sea Foam Motor
Treatment’s exclusive formula is blended specifically to clean carbon
out of the engine as the engine is run. This is accomplished by our
cleaning oil formula described in #3 above, which dissolves the old
sticky fuel residue that holds the carbon particles that accumulate over
time. Once the varnish residue is liquefied, the carbon particles are
free to be safely blown out of the engine through the exhaust system.

5. Stabilizes fuel. Sea Foam Motor Treatment adds volatility to fuel and
slows down the rate at which that fuel loses its ability to properly burn.
When added to fuel and the fuel is in properly sealed containers or fuel
systems, Sea Foam Motor Treatment is a fuel stabilizer for up to 2
years. Always run the engine for a long enough period of time to
assure the Sea Foam Motor treatment has been drawn through the
entire system fuel system for complete protection.

Sea Foam | Uses in All Fuels

 

I have used Seafoam for years in many different cars. The first time I used it I thought I had made a major mistake when all the crap started blowing out... It is a good product and in my opinion, a good maintenence practice when used sparingly based upon mileage and use of a vehicle.

I see no reason why the ice in the Prius would not benefit every hundred thousand miles of so for a cleanout but I am not yet familiar with the nuances of the Prius enough to offer a credible opinion.

 

Good to see you posting again.

 

Thanks. We just bought an '07 Prius.

 

Stop using cheap gasoline

Use a Top Tier gasoline that has a good additives/detergent package, like Chevron with Techron.

The easiest way to remove "moisture" from the gas tank is pretty simple, fill up the gas tank all the way. You don't need seafoam for that

I'd check all the spark plugs (preferably after the car has sat overnight) to see what's going on inside the engine. If there's any carbon in there you'll see some on the plugs.

Change the oil and filter yourself and go drive in for a couple of hundred miles and check the condition via the dipstick. It should still be a light amber color - it is dark and goopy already, change again - rinse and repeat.

Other than that I'd check inside the oil filler cap and radiator to make sure that everything else where is fine too.

If everything inside the engine seems to be good then you could possibly have some valve seat issues.

 

I'm really surprised that thus far, nobody has mentioned the Solara going into open loop operation. This is the probable culprit in causing black-ish exhaust on a full-throttle accel. Grossly oversimplifying, in open-loop mode, the computer runs the engine looking only to its programming, and not the output of such things as the O2 sensors. In open-loop mode, the engine is usually programmed to run relatively rich, which under the right circumstances, will result in noticeably dark exhaust, since the cats simply can't process all the extra unburnt/improperly burnt fuel in the open-loop exhaust stream.

 

Would a faulty engine temp sensor lead to such a situation? I.e. the ECU never receives the signal to go into closed loop? I've never experienced this in any of my cars or those in my race club but that doesn't mean it can't happen. Thanks for the idea.

 

Anything that might cause the engine to go into open-loop operation could be the cause. There are so many variables involved, and I certainly don't pretend to know anywhere near but a few of them. I suppose that there are fundamentally two possibilities. One would be an undetected invalid input from any sensor that caused the ECU to go open-loop incorrectly. The other would be a DETECTED sensor malfunction that caused the ECU to "consciously decide" to shift over to open-loop operations. Of course, with no MIL indicator showing, that would be a huge sign that the ECU is not seeing anything wrong with its sensors. Of course, that doesn't mean that there ISN'T a bad sensor that the ECU is failing to detect. That would have some strong potential for causing messed up, perhaps smoky, operation.

This is one that a properly curious and capable tech could have some fun with. Good luck, and I hope it isn't something truly awful, expensive, or both.

 

And let's not forget that the easiest, no-brainer, situation in which the ECU will go open-loop is when you go WOT. If your engine has some wear on it, such that it might be burning just a tad of extra oil (but not massive, extra, blue cloud oil), that alone might account for what's being reported here.

 

Hmmm well you don't have to worry about which gas u get cause they all do the same thing, add additives to get LESS mpg out of gas like detergents and crap. If u want to do a good clean out. Use Seafoam and use more then once. The best would be putting the prius in diagnosis mode and run hydrogen though the system for 30 min. Straight and your stuff will be clean as a whistle. If u need help with this PM me

 

Wow, I know I'm resurrecting the dead here, and I have about 4 posts on this forum (I spend my time on the Land Cruiser forums) so you'll probably just call me a newb, but there's a lot of bad info on this thread. Prii do operate a lot differently than normal non-hybrid cars, but they still burn gasoline in an ICE, which creates carbon buildup just like every other car on the road today. IMHO, yes, we should be opening up our cars as we merge onto the highway or other times when WOT can be done safely. All this stuff about open-loop, cheap gas, cracked plugs, Prius operate differently is just not the whole picture, and ignores simple basics of ICEs.
I found this ancient thread because I was searching for info about the carbon buildup problem I have on my '07 Prius, and I can't just leave it as is. Prii do get carbon buildup. Fifty bucks says if the OP's wife drives slowly her car (Sienna, Prius or anything) also had a bunch of carbon buildup. I just had the heads off my mother-in-law's Subaru, and yep, tons of carbon buildup because she never opens it up. I don't turn wrenches professionally anymore, (4 years into a 5 year science-Ed degree) but I was an ASE Master Tech once and I've seen it dozens of times. All gasoline burning cars are the same, and are prone to carbon buildup, even those with additional hybrid technology.
Argue all you what about how the Prius works, when I floor mine on the on ramp, my ICE is cranked up. Wish the previous owner had done this more often, then I wouldn't have this carbon/ pre-ignition problem I do today. Sorry if this is ranty, I'm off the soapbox now, and I hope this is genuinely helpful to someone or at last opens up dialogue.