problems with BPU

Hope someone can help me please.

I've just had the following fitted to my 94 Jap 6sp TT:-

Blitz Nur spec

both decats

Walborough pump

Greddy BCC

When i initially set the boost to 1.2 bar everything seemed perfect, the car ran beautifully then after a few goes of giving it everything it started to splutter and misfire with slight hesitation so power is lost when on full boost. Drives absolutely fine under normal conditions.

I fitted NGK Iridium BKR7EIX-11 spark plugs probably about 6 months ago and i've only done about 6k miles on them. According to...

http://www.mkivsupra.net/vbb/showthread.php?t=41927&highlight=ngk+spark+plugs

...I don't need to adjust them and they're good for up to 1.3bar. I was hoping it'll be something really trivial like the spark plug gaps but it looks like it isn't.

you know how it is, you spend a fair bit of money, get yourself all excited, then something like this happends

Any ideas/help would be greatfully appreciated.

It might be your plugs are now past their sell by date and need replacing after bpu'ing. Your fuel filter could also need replacing

the plugs and filter were changed at the same time about 6 months ago. I've only done 6k miles surely they don't need replacing that often ???

how much is a fuel filter and how easy to fit ?

I fitted NGK Iridium BKR7EIX-11 spark plugs probably about 6 months ago and i've only done about 6k miles on them.

Did you adjust the gap, the -11 means that they're set at 1.1mm.

You need about 0.8mm for a BPU car.

I would put some new ones in to make sure . I got some NGK BKR7E(6097) from Partco, about £10.30 for 6 - good for a BPU car.

so you think i should try reducing the gap to 0.8mm.

My old man gave me some feeler (?) gauges. I've messured the gap on the spark plug and its reading 37 (37 what i don't no)

Is there a converstion chart for 0.8mm = the number on the feeler gauge ?

Also do you simply tap the top of the spark plug down to reduce the gap ?

sorry if i'm being stupid but i've not done this before.

is that £10.30 each if you buy 6 ?

I`m guessing 37 thou, imperial. 40 thou is equal to 1mm.

I`m guessing 37 thou, imperial. 40 thou is equal to 1mm.

not sure what a thou is ? (i'm dumb, i sit behind a desk for a living)

i think the Feeler gauge actually reads 0.037 inches which is about 0.94 mm

the feeler gauge is so old and dirty i can just about read it.

so agreed the spark plug gap is too big ? and i should reduce them to 0.8mm ?

am i right in saying 0.031 inches is 0.8 mm ?

Actually 0.7874 if you want to get anal about it

Go here http://www.onlineconversion.com/length_common.htm for more

hth Todd

that'll do, this silly feeler gauge can only be set at 0.031 inches

we'll see.

wish me luck.

just got back after giving the car a good thrashing through the lanes and wooohooo no more misfiring !!! now the fun begins...

thanks to everyone for their help and thanks Scarface i've just twigged, a Thou i assume is a thousandth of an inch - i've learnt something new today.

Hope you can get this sorted Steve. If you want some IK24's i can get them at a good price. (Nothing close to 6 for £10 but cheaper than usual )

all sorted thank god, see you soon.