my mystery problem solved

as a few of you are aware I took my gtr on last trackday at brands due to my pulsar letting me down around 20 mins before I was due to leave.

it seemed fine on the sprintday but underpowered to what it should have been.

anyway today I had a look at the car after replacing the entire ignition system, fuel filter, fpr etc etc
but all to no avail as car was still misfiring on boost

so today I decided to bypass the attain swirlpot and run with the single walbro directly from the tank to see what happened, anyway car would start up and idle and be fine up until turbo kicked then mahoosive backfiring on boost so I took the pump out of the tank and fitted another we had.
connected up swirlpot and second pump again and whoosh no more problems

so it turned out that the in tank pump had partially failed and the secondary pump was pulling the fuel through the first pump as opposed to fuel being pushed to secondary pump which made the car gutless

different story now though she pulls like a fookin rocket right round to the redline, flames and all so im well chuffed as I was on the point of wielding my axe on her

thought I would post this just incase any of yous have a similar prob, the walbros don't seem to have that long a life span and you never know the one you purchase may well be a copy pump also.
in my case it was difficult to diagnose as had 2 pumps and neither had totally failed........so be warned guys!

Quite a long time ago I built a car with a warlbro pump in it was actually pumping less fuel than the standard pump.and this was a long time before the copy's were around

Nice one buddy at least it's sorted now, can be sooooo annoying tracking down problems,

Many times I feel like getting the sledge hammer out lol

You didn't forget to tighten the battery terminal this time then?

your never gonna let me forget that one are you gaz

It only makes me laugh mate because all day we had that misfire & it was only battery terminal

Its an easy mistake tho when you are preparing the car for a track day & little things like that slip your mind.

yeah I should have been wearing my big hat with a big D stamped on it that day
who would have thought a loose batt lead though especially as it was in a fibreglass box in the boot lol
just shows you though........never overlook the simple things

Was a good job you found out what it was tho before you started scratching your head replacing ignition parts etc

more luck than judgement tbh gaz
you can call me the master though due to my brilliantness and true modesty lol

Yep ill give you that 1 mate

Lol i always try the basic stuff first but sometimes its easy to overlook them especially if you been at it for hours a good cuppa tea and fag always helps get the brain ticking over

This sounds like what my is doing but I kept thinking it was the det sensor ill change both see what happens

Walbro pumps are far from top quality. Only use Bosch or Jap pumps as the build quality is top notch thus very very rare get issues. Seen too many Walbro's fail or have low output. Bosch maybe a little harder to fit in the GTiR but if done right it will be done once & never need looking at again.

I'm just waiting on another pump from Bob as I'm having fuel problems and the only bit I haven't yet changed is the walbro pump.
Hope it fixes it.

So why are the bosh ones difficult to fit ?

nomad wrote:So why are the bosh ones difficult to fit ?

Not so much difficult more a case of a bit more effort needed in getting pickup right & pipe fitting compared to Walbro.
All depends on what bosch model pump you use too, I used a Bosch 984 which I had on the shelf salvaged from a Volvo turbo, probably good for 450hp & easier pickup mod than the 044 pumps plus it was free so not much debate was needed & in it went.