JamesS

Got a problem (and the solution..!!...) driving in the peeing, P***ING, rain today.

I`m using a small secondary scoop on the bonnet(UK 00MY), feeding a K&N cone.

Been like that for over a year, running 1.3bar. Driven in heavy rain before, no problem.

Today, first time coming onto boost, hit what felt exactly like boost cut. Now I know it wasn`t boost-cut, as such, due to running the limit at about 25psi with a FCD...

Also happened at different speeds and gears....

Off boost running fine, on lite throttle to about 9ish psi OK. Idle fine.

Boost control by AVCR.

Rain stops(ish), normal duty resumed!

Any ideas? Obvious cuprit is scoop feeding LARGE quantities of water onto filter and hence onto MAF. (I know, cones and MAF failures etc)....But why today, and why a boost-cut like failure rather than metals bits in sump and down the road? (Not that I`m complaining!)

Some sort of water lock at the filter end?(Unlikely?)

Some MAF failure-mode that activates ignition cut? ECU has no access to boost control due to AVCR......?????

Cheers!

john banks

It went lean because of low MAF readings? If it goes really lean it may be starved of fuel like a fuel surge feeling.

JamesS

John,

Would the ecu allow that level of fuel reduction based purely on the MAF; throttle position and MAP would be saying otherwise? Could there be a failure-mode for such conditions that cuts ignition?

john banks

Don't honestly know. Difficult one to test, well scary and silly one to test anyway.

EvilBevel

My personal experience leads me to believe it does indeed...

How does 3%CO at full throttle/full boost/5000 RPM/5th gear sound ? []

In short: had this happen once, hope to never have to see it again.

scobymars

last year I had same problem with a no resonator configuration and lot of rain the next day on high way at 5k I blow piston number 4

dowser

I had a MAF fail completely (vibration related) - this leads to huge overfuelling (scarily so) at low load, and a stuttering engine if you're stupid enough to try WOT...there's not enough fuel (MAP is not used for any fuelling decisions AFAIK). I'd imagine a water coated MAF could give the same result, no fuel. Very dangerous

Interestingly, an unresonated car here recently blew his turbo due to water ingress (slicks wore through splash guards...not what you're thinking ) - he didn't report any fuelling/hesitation issues during the day, first he was aware was when turbo actually failed....airbox was *full* of water

Richard

JamesS

A lucky escape me thinks! Time to blank the scoop off!