Think my cars over boosting lads, I took out the plugs and they were pretty white, no damage atall to the ceramic centre etc, but they were a bit white, not to bad

is it possible that a leaky pendulum chamber gasket can cause over boost, it cuts out if I totally floor it in 1st or second and ive recorded boost spikes at as much as 1.76 -1.8 bar

at the mo, ive changed the plugs and im using optimax and 2 cans octane boost per tank,

but I think ive got an air leak will this cause it to over boost ?

cheers Glen

 

just take it easy and get to a good tuner with a rolling road. dont take chances "testing" on the road to try and find your problem. 1.8 bar sound too much for your spec/chip? you shouldnt need octane booster if using optimax and a proper set up....

 

yeh bro im on stage 3 dark greens, t34 with .48

was boosting to 1.55bar before on my last engine thats how im thinking ive got a air leak, and also tell tale sign its fookin quik

 

my cossie is totally standard and i think mine is overboosting aswell....does your engine completely cut out then start itself again after a few seconds?thats what mine does.

 

Whats it tick over like m8
normally air leak causes a slightly faster idle,
I have had that before when the plenum gasket gave up,
Its need setting up to be safe
Itake it after the engine refit nothings be done to the actuator or anyting like that?

 

In any event 1.7-8 bar is too much on 803s

 

nah mate, this is just a hesitation, and normally a big back fire aswell

im not sure what overboost functions the P8 / L8 have built in

hopefully somone more experienced will help out

 

I think you have hit the nail on the head mate idles being to high and erratic, im gonna order a PENDULUM GASKET and fit that see if it cures it mate, and yeh its to high, as I say prior to this boost guage was only recording 1.6 bar peak

 

Really? Depends where in the rev range it makes that amount of boost.....

Glenn, octane booster can affect the 'colour' of the plugs I believe, you certainly shouldn't need two cans of it with Optimax imo.

Is it doing that with a full tank of petrol now then too?

 

Hi...if its a spike ie....goes to 1.8bar then drops off at the top...then its FINE.....i ran a 2bar boost spike on my 803 setup which settled back to 1.7bar..but i raised the fuel pressure to hold the 1.7bar......the only time you aint got enuff fuel is if you held the spike to the line in every gear on your car mate.

 

its hitting 1.7-1.8 bar boost about 4k rpm in 1st and second mate, and yeh same with full tank fuel

heres a pic of a plug mate, but im pretty sure this is an air leak / gasket gone / damaged

 

Spray WD40 round the Plenum chamber/gagket and if the revs rise...theirs your problem. a leaky one however WONT cause it to overboost, if anything it will under-boost as boost is escaping, and it could possibly cause it to cut out too yea.
white plugs im sure is a sign of overfuelling, someone will correct me if im wrong tho. get it to a RR, AVA in Glasgow are your best bet mate.

 

p.s the phot makes it look whiter than it actually is, with the flash

 

The plug should be a greyish colour to light brown for perfect...That looks ok to me assuming it has a greyish colour to it.

 

the L8 doesnt have any overboost strategy (i dont think) whereas the P8 allows upto 5 seconds IIRC.

could just be the wastegate actuator needs setting, set the boost to 1.5 bar.

 

ah cool mate, thats a relief, it drops back fine yes on full chat its only boosting 1.5 ish, but ive still got s feeling the gaskets gone, re the chaps comments on the idle as it is not idling well, to high

 

slightly better one this mate

 

cheers dave

 

Hmmm....seeing them again...i'd say too much air not enuff fuel...BUT i am far from being a tuner!!!!


.....and i am awaiting to be shot down by a pro

 

they do look a bit leanrunning , BUT if it has been boosting to 1.8 bar , and the chip is mapped for 1.5, what can you expect.

 

Dave......chips are normally open ended..ie the more boost the more fuel....until there is no fuel left then just air ..thats what chips i always had.

 

yeh lads LOL i know that what im wanting to know is will a leaky plenum chamber gasket cause it to run a little lean, and is that whats causing the high idle aswell

 

IMO...yes Bigman

 

that maybe true, but, things are not linear in the real world, airflows, charge temps etc all combining will cause a leaner burn even if you could match the A/F ratio exactly until the injectors were on full duty cycle.

 

cheers mate
and thanks dave etc for all the help

 

Plenum gasket is a weak spot m8
i got a cometic one on mine is i blew a piece out of the bottom of the standard ford gasket,Glenn 5 on here lives near me and he had the same thing happen thursday night after the Local RS meet.
Take the plenum off have a look
It will most likely be that or the inlet (inlet is less likely)

Oh you overboost should be fine i was talking more about a held 1.5bar on greens as a safe limit

 

sweet cheers mate, will buy one then just change it and report back to this thread in a few days

thanks

 

btt for the nite shift boys