someone also mentioned to me the removal of the UIM throttle plates could cause it?

 

I've had mine removed for years with zero problems.

Dale

 

Is anything different about your MAP sensor and plumbing? Have you changed the length of the vacuum line, or moved it to a different nipple on the intake manifold? Have you tried logging the raw MAP sensor voltage and raw fuel pressure sensor voltage at the fastest rate possible?

 

u can see the short term increasing where blue indicator is.

 

I have not tried switching ports or length of hose for map sensor. I believe it is still hooked up to stock port without that filter thing that was inline to stock map sensor.
I'm running after market 4 bar map sensor bolted to same spot as stock

 

swapped throttlebody and maybe a minor improvement.
starting to run out of options, anything its possible maybe engine harness is at fault?
still has all the twin turbo and emissions stuff attached

 

is drivability impaired? does it miss or hesitate? If it drives just fine and not hurting anything why not leave it

 

when the map is compensated it drives fine
I want to figure it out since something seems to be wrong. tuner has never come across this issue before. he put a lock on boost till we figure it out.

 

I've been running lean as well and cooking the twin turbos. I took it to a local shop where they diagnosed the engine as running healthy but the air pump was causing the lean reading at the exhaust side...so we disconnected it and seems to be running fine now as a temporary solution

 

just wondering if this issue got solved? i have a very similar issue. running lean at 2500rpm. car was stuck on a dyno for 2 days with even haltech logged into car while running. it doesnt seem to be ecu or fuel. engine runs sweet after 2500rpm ecu is an elite, enging jc cosmo 13bt efr 7670

 

I think the consensus In some other thread is running aftermarket rails/injectors with no fuel pulsation dampener. I believe you hit a certain pulsewidth/fuel pressure where you get some funky resonance in the fuel supply which creates a lean condition.

Dale

 

never thought about that! I should look into that. just seemed weird alot of guys run no dampners and dont seem to have issue.
I still have it and I've replaced all kinds of things including the engine harness.

 

interesting! il ask my tuner and see what he thinks. we thought it might be the plate on the rear of the lim leaking as it has been welded on. but it all looks fine. i have removed the whole manifold to give to the tuner to have a look over. they did do fuel pressure checks to see if its spiking but it was all fine.

 

what tuner are you using? mine seems to need about 15% or so more fuel. yours need that much too?

 

my tuner is here in Australia. they only tune haltech and are a specialised rotary shop. not to sure about the amount of fuel added. i had it tuned after run in. since then i done some work to it and sent it to this place. they are saying the last tuner has played with the numbers to make it work. that's how i found out. i am low on hp and full boost is not kicking in till 4500rpm. it runs sweet after it

 

think I may try the fuel pulsation damper a try. might go with the radium unit and put it on secondary fuel rail.
think it matters where it goes? my issue only seems to be with the primary injectors running

 

from factory they had on on the feed side of primary and discharge side of the secondary rails. i could be wrong tho. yea mine is also in the primary as well. if you are sucking in air anywhere that can do it. ive currently got the manifold off to take to the shop to get checked out.

 

I have smoke tested mine and didn't find leak

 

just took manifold to the shop. i have a plate that has been welded to the back of the lim. they think it "could" be leaking under the plate as there is 2 openings. the plate should be bolted on with a gasket not welded. i asked them about the pulsation dampener and they thought about that. they are saying my fuel is bang on.

 

which brand and size injectors are you running?

 

ive now got 4x 1650cc bosch injectors. ive got my manifold back. they removed plate from the back of lim and welded up 2 vacuum holes. will b olt it back on and see if it makes a difference

 

keep us updated. my next step is adding a fuel damper and sending injectors to ID to get flow tested

 

got car back together. boost is coming on earlier now but im not 100% sure if we have got the lean spot sorted. car will go back onto the dyno to see.

 

o interesting! good that boost is at least coming on sooner

 

If you don't see boost until 4500 rpms with an EFR 7670 than something is seriously wrong with the setup.