14 replies to this topic

[77LeylandMini]

It all started when a gas station sold me ethanol in a pump labled as 93 octane.. flushed the fuel tank out, cleaned out the carb, got it working again. About once a week I had to raise the idle... then every once and a while it would sound like and feel like it went down to 2 cyl. sputtering, not going anywhere, kind of a machiene gun sound. On a break from work the other day I was messing around with it- I had a hunch it was the waxstat playing up, the ethanol ruined the line from the float to the jet, when i gave it a slight tug it fell out. So I figured I would kill 2 birds with one stone. I had a spare carb at home with a fixed jet. put it on, it was running better, but theres the crazy loss of power again!!!! then just like that -gone.
plugs look good. It does have points, might be suspect, coil looks old. I just hate spending money hunting for the problem. any ideas?- Also- every once and a while there is a slight almost unnoticable "burp" in the engine. compression is also good across the board.
Thanks !
Ryan

Oh! and one more thing- dont know if it matters but since I got the car it ALWAYS runs on when the key is cut off, even with the timing WAY advanced and the mixture lean?!?!?!?!

[TWICEmonkey]

This is a little off-topic, but didn't you get any compensation from the garage?

Their mistakes seems to have screwed with your engine!

[Jimmyarm]

The running on could be caused by the spark plugs, mine didnt do it until I put Bosch Super fours in, something to do with them not transferring the heat away as well I believe ?

[77LeylandMini]

It was a major gas station chain in the us called "citgo"... I called their headquarters- they told me "Ethanol is the way of the future! better get used to it" I told them that thats fine, but label your pumps accordingly!!!

[TWICEmonkey]

Ethanol maybe the way of the future, but it's not the way of the Mini....sue the w*nkers

[Dan]

Since running lean is one of the prime causes of running-on, leaning it out to try to fix the problem isn't going to work. All it might do is melt a piston crown or two.

Running-on is caused by excessive risidual heat in the combustion chamber, any number of tuning problems can cause this but most commonly its carbon build up, lean running, ignition timing or bad build. Excessive compression ratios can cause the heat (that's how diesels work after all), poor component selection or anything like that. Sometimes the exact engine build you want will result in running on and in those cases a purge valve can be use in the induction system to flood the engine with air as soon as the ignition is cut. If however the engine is running on simply because it's in poor tune, the best thing would be to fix it rather than use a valve.

How's your fuel pump by the way? The ethanol will have affected any rubber and some plastic parts of the fuel system in the same way as the jet hose, including the pump internals. You should consider replacing all of the rubber parts in the system. Including things like the fuel sender gasket and possibly float. The carb float could also have been disolved, although you did say the carb has been changed so that's probably not the problem.

Edited by Dan, 29 June 2006 - 04:40 PM.

[77LeylandMini]

Thanks for the education!!! I was told that engines "diesel" due to an excessively rich mixture!! I may have found the problem afterall- Just got back from the auto parts store, got some plugs- same result... When I pulled the HT lead off of the coil I noticed some oil coming out of it. When the wife comes home I will use her mini to go back and get a coil.
Thanks again!
Ryan

[miniboo]

OR just nick her coil lol!!!

[77LeylandMini]

@$#@ remembered that I had a spare coil in my spares bin. not it..... same thing- only on my way back from the parts supplier it started acting up and didnt stop, so it looks like the intermittent problem became constant. good and bad i guess- I will know when I fix it, but I cant drive it!!! I got worried when I saw what Dan posted, so I checked the compression again. 175 in every cyl- Isint that slightly high??? better than low compression though! so, its not the plugs, not the coil, not anything to do with the carb, new fuel filter, fuel is indeed flowing, i can see it in the filter. I guess im left with points- condensor, HT leads.... anything else?? I cant stand points so I will probably switch to the pertronix electronic conversion.
Ugh
Ryan

[Dan]

How long did it run with ethanol in it?

[77LeylandMini]

about 5 miles, then i turned around and drained it

[TWICEmonkey]

I haven't got the book in front of me, so I can't remember the pressure it should run at, but if it is high pressure, it can cause pre-ignition ue to the build up in heat...don't forget, that's how diesels ignite their fuel

[miniboo]

175 is ok.

[retrodan]

have u checked dizzy timing! running on can be fault with advance/ retard on dizzy! but on some minis with engine mods after a long run they do it a bit anyway!!

[Dan]

Since you appear to have been all through the fuel system and tuning I can only think that there must be some internal damage. I don't know exactly what but I'd imagine the ethanol could have done something to the valves. If you only did a few miles though I can't think there'd be that much damage.

I believe that ethanol burns relatively cold compared to petrol, it's about two thirds as powerful in terms of heat output. This could have similar effects to lean running I suppose and with your car already tuned lean to try to prevent the dieseling it could be that you are seeing the engine damage normally associated with protracted lean running in a much shorter time.

I think I'm just rambling on a bit now so I'm going to stick with the valve gear for the moment. Do all the inspection of the valves that you can without taking off the head. Check with the rocker box off that they all move nicely and that they all line up to about the same height (this will tell you if they've started to receed).

Don't really know how else to help. This could all be unrelated to the ethanol and just be a different tuning problem that's chosen now to present itself. Of course the car having been running on won't be good for it, that wears the engine pretty fast.

Edited by Dan, 30 June 2006 - 12:08 AM.