lean issue, help needed
 

hi, have a v3 type r , vf34 turbo+turbo back exhaust and have simtek fitted,
the car is away being mapped at the minute (or last 2 months) and is giving the tuner a complete ballache, the car runs perfect until approx 5.5k rpms then goes big time lean, doesnt matter how much fuel you give her or how little boost it goes lean.
fuel pressure is good , no maf .

this only happens at wot at 3/4 throttle the car pulls no problem .

any ideas before i put a match to it:(

cheers

Thats an easy one take it to Andy f.
Is it a well known mapper whos doing the job. Dont name names.

cant do it man, not in the country

it not a mapping issue, well iam pretty sure its not

agree i bet your maf needs re scaling m8

not running a maf with the simtek

fuel filter clogged up?

Boost leak?

Lean issues.
 

Have you spoke to steve simpson? Simtec designer and builder. Hes ur man for this problem. Find him at teg sport in carnforth. Tim.:thumb:

New fuel filter , have checked for boost leaks and all is good.

What injectors, what fuel pump and fuel pressure reg ?

There are several things that can influence this sort of problem.

cheers

bob

Hi bob , the injectors are the standard yello ones , they have been removed and checked and are 100%. The car has a high pressure pump but have no idea what make it is , as for the pressure regulator I have no idea.
Cheers

So 440cc injectors, if running too much boost they will be maxed out at about that rpm, so thats one thing to consider, you strictly need 550cc injectors with the VF34.

Fuel pump ... that could be "failing" I have seen so many 'WALBRO" pumps that aren't ... even brand new ones which simply don't deliver what they are supposed.

You say fuel pressure is ok, what is it at idle, what is it on boost at wot, std pressure is 3 bar atmospheric, so at 1.4 bar you should have 4.4 bar pressure for example.

The std fpr would probably still be ok, if an adjustable aftermarket one then there are some that work well and some that don't.

So ...

Injector duty's ?
Fuel pump

Those would be the first two things for me.

Assuming that all pipework etc is correct and intact especially the pipe from the inlet manifold to the fuel pressure reg !!

best regards

bob

thanks bob ,
the fuel pressure at wot is just under 5 bar iirc , the car will still run lean even when running .5 bar of boost at wot but at 3/4 throttle it pulls no probs running 1 bar.
as far as i am aware the fpr is the standard one.
car also has a forge dumpvalve vta (forgot about that )

could a dodgey iacv be the cause, code 24 was the only fault on the car with the standard ecu.

thanks
all help much appreciated
curtis

anything else anyone?

????????? ffs

up tay fook

If you`ve tried everything else, I`d remove the Forge dump valve as these can be prone to leaking under high boost which it seems like you are running as just under 5Bar of fuel pressure means your putting nearly 2bar of boost through the VF34 if you take off the atmospheric fuel pressure,

Is it overboosting?
Where are you getting your Lean readings from AFR gauge/Simtec etc...?

hi , getting it from a wideband while on a dyno, its not overboosting its runs lean at 5.5k at wot at any boost .7 bar 1.2 bar doesnt matter , the car is getting fuel ( so iam told). i am not tuning the car just trying find out whats wrong with it so i can get it back,

soooo the dump valve cant be culprit if it still falls lean at .7 bar?

It could be as it could be leaking full stop regardless of boost levels, Is it not worth swapping it over to check and then at least you can eliminate it from the problem

i dont have an original one , only runs bad at wot 80% throttle it runs perfect.
will get it swapped with something else to to see.
cheers

To put it bluntly it is going to be very simple as to why it is running lean. My fault finding process would go like this:

What size are the injectors are they capable of doing the job?

Is the fuel pressure going to where it should on boost and not tailing off?

What numbers are there in the fuel map, am I maxing the injectors?

Is it not worth considering external help, i.e getting it looked at elsewhere perhaps? I don't know the true extent of the problem or what the tuner has tried, but it should be fairly obvious where the problem lies, it just may not be a quick fix.

Graham

yes graham , i would very much consider external help but there is not too many choices in n.ireland, as for the tuner i have no idea what he has tried but i am getting pretty pissed off with him , you are right it should be pretty obvious i would have thought if the car is running lean there is only so many things it can be but he says he cat understand it.
anyway i have given him a deadline at the end of january(had the car 4 months) fix it or put her back to the way it was then take it to our only specialist.
good times
cheers

Mapping in N.Ireland probably in march, happy to help if I can.

Simon

thanks simon that would be perfect, will see what state the car is in when i get it back in 2 weeks. will be in touch
thanks

I hope its sorted

Post #23 says your going to take it to your only specialist. why did you not take it to him first. whos looking at the car at the minute. pm me if you like. John.

I was trying to get the car booked in for 3 months , they didn't seem interested in doing the job, the guy doin it isn't a Subaru man but don't think it should matter , don't want to give his name because I know he can get great results from other models