Tank O'Seafoam - engine's not happy...
 

So, I just changed my oil and thought I'd throw some Seafoam engine cleaner in the gas tank, too, as a little extra treat for my baby. I usually use Techron, but had heard nothing but good things about Seafoam and thought I'd give it a try.

Well, now I'm getting a very reluctant Mini. It feels similar to the throttle response/stumble problem we've all read about (and many have felt). The car starts and chugs/stumbles immediately. The rpm's recover and the car returns to a normal idle, however, upon "blipping" the throttle quickly, the rpms actually drop and the car chugs again and slowly recovers to normal idle. If I were to stay on the throttle and pull into traffic, the engine will eventually catch up, assuming I didn't just pull out in front of oncoming traffic and get smashed.

It seems that if I stop, turn of the car and restart it, things get better. Is this just the ecu trying to account for the differences in this tank of gas? Should I just deal with this until I get through this tank and see what happens? Has anyone else experienced this? MOTD is coming up and I hate to be running less than optimally for that!

I think I read somewhere that seafoam lowers the octane of the gas, so this might be the issue. Again - I read that somewhere and don't know if it's true or if it's what's causing the behavior you describe. I've never had any of those things happen after putting seafoam in the gas tank.

mb

Hmmm. I guess if it lowered the octane, the engine would need to make adjustments, right?

if it does really lower octane...maybe get some octane booster and see if it helps

I just hate to keep adding things to my fuel and turn it into a chemistry set, you know? I don't want to end up getting picked up by Homeland Security for inadvertently turning my car into a bomb or something!:eek:

If anything, Seafoam would raise octane. Higher octane is less volatile, burns cooler, harder to ignite. It's isopropyl alcohol, naptha and mineral spirits.

So, I guess the real question is... Assuming the most significant difference in a tank of gas with or without Seafoam is the octane, would such a shift in octane cause this noticeable a change in engine performance?

Your engine must be really dirty. Seafoam has never caused stuttering in my car. Just try to run it through, maybe add some gas halfway through to try to lessen the concentration.

Really dirty? As in, I waited too long since the last batch of Techron? How would a dirty engine + seafoam = stuttering? (I'm not challenging your comment, I'm honestly uninformed and curious!) I believe it was one of your posts that pushed me over the edge to pick up Seafoam in the first place. Sounded like you use it pretty regularly?

How big of a can did you add, and how much gasoline was in your tank? You might have over-concentrated it, but a "normal" dose can be as strong as two ounces per gallon, so unless your tank was low, even a full pint of Sea Foam shouldn't cause problems based on concentration alone.

I added a full pint (I think it was the only size they had, I'd guess it was a pint based on my extensive experience with pints of other kinds:wink: ) to about a quarter tank of gas, then filled up as usual with 93 octane Shell. From reading the label on the can, I don't believe there should have been any issue with concentration...

If you have a large amount of buildup in your fuel system, Sea Foam can cause it to break loose in "chunks" big enough to partially clog your injectors and cause fuel atomization issues.

If you only have a small amount of buildup, the gunk just gets dissolved into the gasoline and passes through the injectors with no problems.

But as long as your engine is running, even larger bits stuck in the injector nozzles will eventually dissolve away and pass through.

Sounds good - I think SF only comes in pints and gallons, so you obviously had a pint can. And a full pint is a perfectly-appropriate concentration for a 14-gallon gas tank - almost perfect, in fact.

So, just "ride it out" and see what happens over the next tank or two?

Yes - I've had similar experiences to yours when using fuel system cleaners on old motorcycles. As long as the engine is still running and fuel is still passing through the system, the engine will smooth out pretty soon.

Scott pretty much covered it. Yeah, I've been using some sort of fuel system cleaner regularly since the car was new.

Cool, thanks guys. I just had flashbacks to the first winter I had the car. It was brand new and with the fuel mix and temp changes, it started doing something very similar to this. They updated the ecu and gave me the top tier fuel speech. Until now, things have been pretty good. I guess we'll see what happens.

Thanks again!

Take a nice long ride
 

Get in that Mini and take a nice very long ride down the interstate. When putting any cleaner in the gas you should always do it when you have time to drive a nice long distance. None of the cleaners really work as good as they should if you just stay around town with stop & go driving. Techron, STP total fuel system cleaner, Sea foam are all very good at what they do. I always used STP Total fuel system cleaner in my 98 Corvette to mostly keep the fuel gage slides from sticking. I don't think Mini has the same problems as the Corvette had so I will probably use Techron at about 10,000 miles or so. I get my gas at Sam's club here in Daytona and really don't have a faulty crap/gas problem.
Let us know how things work out for you.
Ronnie948

I had put about 70 or 80 interstate miles on this tank of gas after I put the seafoam in on Sunday. I didn't notice any problems until monday afternoon. I should be on the interstate again tomorrow night, but only about 70 miles round trip. I'll see what I can do!

If that was my car I'd siphon all of the gas out or as much as I could. Then I'd refill with a good quality fuel. For what ever reason your MINI is not feeling the seafoam love. :no:

It's Techron for my MINI.

DON'T SAY THAT!!! You're gonna get me all freaked out! I've always used Techron, even if Seafoam isn't as good (which I'm sure could spark a HUGE thread here) I can't imagine it being BAD for my engine.

Now you've got me nervously looking for reassurance!! :confused:

Happy Thoughts Happy Thoughts Happy Thoughts Happy Thoughts!!

I call them like I see them. Like I said... if it was my car.... but it's not my car, it's yours. Siphoning out that carp in the tank is no big deal. Or drive it until the seafoam contaminated gas is outa there. Flip a coin, it's your choice.

I'm sorry to have upset you, but IMHO if your MINI is acting poorly after pouring that stuff in the tank, seems to me you'd want that stuff out of there. Did you really think your MINI was all carboned & gummed up to need a seafoam treatment?

Why bother with the Seaform or techron at all? Shell has a very good additive package in their premium grade gasoline.

Never used any additives, and my car runs perfect, and has dynoed strong. :)

Adding cleaners like seafoam as often as I do is probably extreme overkill but, it gives me piece of mind.

We need some kind of test...
To someone who has never used seafoam or equivalent and has about 56,000miles on their MCS - continue not using it. I'll keep using it at regular intervals. Then when we each reach 150,000, 200,000 miles or whatever, we can inspect the internals when the engine is torn down to replace the bearings and piston rings. Then we will know for sure.