AJ-RST1

iTrader: (2)

as above my s2 has developed a backfire when i turn the engine off.
running rich?

andy130

iTrader: (2)

could be over fueling mate

AJ-RST1

iTrader: (2)

it seems ok when drivin it, just when i turn it off. gettin it set up by harvey gibbs next week hopefully

orionmojo

iTrader: (1)

mine pops on cold startup... Go figure!

also it sometimes pops when its turned off, but its only done both since it was setup at nms. it runs fine, and sometimes pops on gearchange too, which i love.

rstdave

iTrader: (3)

Mine used to do this when it was on mfi....if i'd been driving it hard it would backfire pretty loud when i turned it off! No longer does it now it's on efi, think it must be the mfi chucking too much fuel in, nothing to worry about.

Karlos G

iTrader: (4)

Yup MFI overfuels like mad any time other than full load WOT or idle.

mr_joe0606

iTrader: (1)

mine does the same when i turn it off give it a couple secods a little pop. but when you let it cool down 4 like 2 mins or over it does not happen. just lettin me no its still there lol

Red_bull

mine does it to, but i'm going for a set up when i got my new radiator, so maybe there will be a change

RSTurboSI

iTrader: (1)

Mine Bangs all the time, Off boost on slow down normaly, sometimes on cool down it does pop also, and when turn off it also backfires, buts its over fueling anyways

Chopshop85

iTrader: (4)

Its a classic mfi trait I think.. especially if youve been for a blast. Mine does it about 10-15 seconds after ive got out and locked the door sometimes lol. Always has done, even after various parts and several tune ups in its life time.

mk1trb

think its jus too much fuel on idle in a hot engine and exhaust, nearly all my rs' do it

MunkeyboyRS

My rs very rarely pops or bangs loudy, and even more rarely spits flames out, now mate one is like a flame thrower! is down to my shit exhaust?

Karlos G

iTrader: (4)

No it's beacuse yours is leaner than his, nothing to do with the exhaust mate.

NEILNATO

I came across this prob with mfi, what i found out is the 5th (cold start) injector was dribbleing fuel due to the pressure in the system, which is still there after you switch the engine off, so the fuel vapour finds its way into the hot exhaust manifold and det's making the pop you hear, change the injector (for those who dont know, its the one under the inlet manifold) and it will remody the pop.

Karlos G

iTrader: (4)

Unlikely, but it would be the cause of rich running in general

MunkeyboyRS

ahh cheers dude, I had been wondering, as I did think my car should be running rich as i changed the metering unit and i was told by my mate it was running rick on his car, and i'd just been lazy and not re set it, but couldn't help thing why wasn't in not popping more at the same time.

Karlos G

iTrader: (4)

If you've changed the metering unit go and get it set up on a RR or your risking you engine mate, specially as it appears you are a little lean!!

MunkeyboyRS

What probs can it lead to? its been like that for about 3 weeks

botters

iTrader: (2)

if lean melted pistons for starters! if too rich you get bore wash which can cause unburnt fuel to seep past the rings into your sump degrading the oil and shafting yer crank! i found this out the hard way!

Karlos G

iTrader: (4)

Exactly! Get it setup mate, really important!!

DazC

iTrader: (1)

this is also a symptom of running lean believe it or not.