busa4

air leak? what did you do for fuel mods again?

nickrocks

fuel mods are vortech 12:1 fmu otherwise nothing.

im almost positive that theres no leak but ive been wrong plenty of times before. ive cheked and tripple checked for leaks thinking myself leaks would be most likely the problem.

fuel pump builds an maintains pressure at 80 psi.

the engine now boosts 8psi but it leans out and stays around 17:1 afr under boost but watching fuel pressure its staying at 80 psi.

while driveing and boosting it just feels like it isent makeing power. probly due to the lean condition but with the new actuator at least the wastegate is keeping boost down to 8psi and not popping.

at this point im positive the computer or injectors are not working properly.

the friend of mine that i mentioned earlier is still haveing great luck with this exact same setup and never ever goes leaner than 15:1 even under full boost with no fuel mods of any kind. and hes makeing more boost than i am.

wtf?

if megasquirt wasent so over whelming to me id try it but im 100% completly lost when it comes to wireing or even makeing any sence of schematics.

busa4

when using an fmu you need to replace the fuel pump. as pressure increases, volume decreases so you need a pump that can support high pressure. a walbro 255l high pressure fuel pump should solve your lean boost problem. as far as being lean under natural aspiration there must be a air leak or a failed sensor causing the lean condition.
find out from your friend exactly what parts he has on his setup because ive never seen a high boost vehicle using only an fmu last longer than a couple of trips down a track. he must have larger injectors and an fmu.

nickrocks

im so mad right now im about to give up.

ive bothered him over and over about what else he did to make his engine run. he swears and i believe him that there stock injectors and that theres no mods to fuel at all no fmu. nothing.

what sensor could cause this?

i just installed a in cab fuel pressure gauge so i could monitor the fuel pressure. it will go from 35 to 80 psi and never droppes at all while under boost. even when i boost up to 8psi. it will hold 80 psi so to me its not a fuel pump issue.

ive just installed new mas airflow and a new 02 sensor wich was rediculas amount to pay for those parts.

im gonna look again for air leeks today maybee ill use air pressure and see if it holds.

thanks for the help im lost at this point.

busa4

a walbro 255l/h fuel pump will exceed 80 psi without sacrificing flow volume. the stock pump can only produce the 80 psi and its working hard to do it.

theres too many sensors than can cause a lean condition. do u have a check engine light on?

the most common air leak in a home made turbo system is boost pipe leaking or the bov isnt adjusted right but it looks like you have a recirculating bypass valve setup. how did you route it?

nickrocks

pretty simple blow off just returnes to the intake before the turbo but after the mass.



hear you can see how it all lays out. the mass airflow is before the airbox. i thought that by moveing the mass to the intake pipe it would change things but it ran exacly the same.



as far as the fuel pump goes im listening to what your saying but if the gauge says its staying at 80 psi the hole time it under boost wouldent that also mean its makeing enouf volume also?

ill buy a new pump i just think that theres another problem and it will take a week to get a new pump here not to mention figureing out how to route it. theres an in tank pump right now.

as far as i know theres no injectors that innerchange with these otherwise id buy them too.

busa4

the only other thing i can think of is the air intake temp sensor. where did you put the sensor? if the sensor was left unplugged the computer will think its 285 degrees air temp and lean out the fuel and retard the timing.

busa4

if larger injectors are used an ecm tune is required.

nickrocks

i snagged a iat sensor last wek at pick n pull ill throw it in there. the stock iat sensor is still in the stock location screwed into the airbox.

ive noticed something durnig warm up the engine is running around 14.5 afr and bounces around a bit but stays close but as soon the water temp hits 160 or so the engine will run a little rougher and will then lean down on the afr. i wonder if its switching from a preset warmup stage or something.

almost like a cold start preset or something.

its an obd1 and the check engine light is off, when i run the jumper to see if theres any codes it flashes 1 pause 2 wich is how it says everthings ok.

the factory service manual says the engine should be running at 14.7 at idle wich it isnt, but the computer isnt throwing any codes im startin g to think it may not be working correctly. in the factory manual it says if i were diconect a sensor say the colant temp sending unit it would cause the engine to run in limphome wich is a preset setting that will run the engine really rich. mine dosent run rich at all when i unplug that sensor.

i almost think that the computer is just stuck in a position and not hbelping to control the engine.

busa4

ok that explains it. the computer runs off a map in open loop till the engine warms up. when the engine warms up then the computer goes into closed loop. closed loop means the computer is now adjusting the afr based on sensor data. the computer is doing its job but its only as good as the data it gets from the sensors. this was the issue with obd1. the software had very little parameters to check if sensors were failing or giving false data.

try unplugging the maf sensor and trying it again. if that doesnt work then try unplugging the o2 sensor and trying it again.