P1DOG

Every now and again the turbo boost drops off considerably on my P1. It seems to happen during / after a good long sprint down B roads or even somtimes when I swap fuel brands (ie Esso SUL - BP SUL and vice versa)Fuel problem may be down to inconsistent 98 rated fuels but why would it drop off during an 'enthusiatstic' drive. Loss of boost is less obvious in the lower gears,but when trying 'maximum attack' in 4th or 5th it is noticebly slower and very frustrating.

Any clues please?

Cheers, Rob

JIM THEO

Are you sure it isn't fuel starvation when your tank is under 1/4?
Just a thought.
JIM

P1DOG

Jim
Cant see thats the reason when the loss of power becomes a permanent feature or full power comes back very slowly over a period of time (like 2 days!)

swaussie

I am having a similar prob with my STi7. I am starting to think its something to do with very cold and dense air because at temps around or below 5 degrees is when it seems to happen. Engine definately goes off boost but I dont get a check engine light, just a sound like the engine is missing badly? If I back off for a few minutes its fine but only happens in 4th or 5th under WOT. always run 98 octane from the same garage and no mods to the car.
Anyone have any thoughts on this?

nom

My guess would be cold weather,leading to higher boost, leading to random det, then the ecu panics & cuts boost for safety. That would certainly fit in with the P1, which runs rather optimistic timing AFAIK. Also, during/after blasts the intercooler would have heat soak & therefore increase the problem, as could a dodgy (or just 'not perfect') batch of fuel.
I'd have thought that the easiest way to 'check' things is when the car is running right (or after an ECU reset), get a reliable SUL (optimax can be a bit station-dependant) - Esso seems the best stuff - and chuck in one of the good quality boosters. Then see if it happens. Doing that should at least reduce the problem. Maybe... or get one possible cause out of the way, anyway
Or, do it properly & get a knocklink & lambdalink & check things that way