yep you herd it right i have drivin my mini over 50,000 miles now and have not had the yoyo ever happining now just a week ago i had pute on the pully and plugs and now i have developed a yoyo, while excelerating, now i have disconnected the computer and then reconnected it and the yoyo went away and it excelerated like "butta" then after a mile or so the yoyo started again and got worse,

has anyone experienced this me and ryan are trying to pute an answer to a queschin here, and any other info would help greatley, we are trying to deside whether its hardware or software, hardware being sensores and such, i geuss theirs more queschines than answers.

 

That really sucks. I never had the yo-yo or hesitation problem and I got a pulley installed in August (2300mi) - but as soon as the cold weather set in (8500mi) - I got hesitation after shifting gears. In some ways, I think its partially due to cold weather, because thats when the weather gets better these things go away.

Maybe the latest software will help...
Erik

 

Try putting your old plugs back on to see if the problem is still there.

Edit: In another post, you said you got an intake at the same time too. Do you still have that installed?
_________________

1/4 Mile Database

 

yes i do but i had the madness before and no prob

 

Andy, I have a similar thought to you: rule out the variables by putting the stock plugs back in. However, when I think about it, the yo-yo is in its' core, the throttle body fluctuating. How would you deduce the plugs having an effect on this?

Also, to compare/contrast, my '04 MCS has yo-yo'd since day one, regardless of the state of Pulley, ECU mapping, plugs, intake, boost gauge install, etc..

 

yah, this is what i was talking about on the other thread.
i think you're running too lean with oxygenated gas, cold
temp, plus added boost. the fuel in the wintertime is bad.

im sitting here lowering 3psi between my summer and winter
boost settings on my wrx while you guys increase psi as
much as 4-5 without chaning fuel or timing settings.
you're probably knocking/detonation.
too bad there aren't knockdetection/auto timing retard
programmable ECU piggy backs readily available for the
MCS yet.

if i ever considered a pully, i would definitely go for the
ECU upgrade especially since its gets like 20F in the wintertime
in chi-town.





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03MCS IB/Blk: 123, Aerokit, R90 17x7, TK5 16x7, 6CDMP3, and a few more.

 

has anyone datalogged the manifold pressure and throttle position during the yo-yo-ing?

 

I would, but my car doesn't yo-yo.

 

always had the yoyo it comes from the trottle body how to fix it is easy put a 19% pulley or a big bore trottle body and its gone.......mario

 

>>yah, this is what i was talking about on the other thread.
>>i think you're running too lean with oxygenated gas, cold
>>temp, plus added boost. the fuel in the wintertime is bad.
>>
>>im sitting here lowering 3psi between my summer and winter
>>boost settings on my wrx while you guys increase psi as
>>much as 4-5 without chaning fuel or timing settings.
>>you're probably knocking/detonation.

It's a good point. But if it's true, my car car did it all summer on 94 octane, pre pulley. That would still mean a flaw in the system, as delivered.


>>too bad there aren't knockdetection/auto timing retard
>>programmable ECU piggy backs readily available for the
>>MCS yet.

It has one, I think. It could in theory, I guess, be a contibutor.

>>if i ever considered a pully, i would definitely go for the
>>ECU upgrade especially since its gets like 20F in the wintertime
>>in chi-town.
Not all ECU upgrades rewrite the same things, from what I've read.

 

the ecu adapt it self with temp ad or retard timing and ad fuel obd 2 ecu can do every thing i built a cooper for racing with 30psi of boost witout changing any thing on the fuel or ecu amazing......dyno the car at 525wheel hp

 

>>the ecu adapt it self with temp ad or retard timing and ad fuel obd 2 ecu can do every thing i built a cooper for racing with 30psi of boost witout changing any thing on the fuel or ecu amazing......dyno the car at 525wheel hp
Did you mean 225 ? Or did I miss a joke somewhere ?