leaning out?

[fierojapan]

ok i am new to turbo cars and i have a question. i installed a wideband on my car and have been messing with the boost to see where the stock computer leans out at. now i am not sure if this is right but it dosent matter if it is set at stock boost or at anything up to 1.5 bar but it seems that under hard acceleration the car will richen up to about 11:1 and as you hold it at full throttle it will lean out. like i said i have tried this at several different settings and have let it get as lean as about 13.something to 1 before i let off the throttle. does this sound right or should it stay rich the entire time i am on the throttle? the car seems to heve some other issues that i am trying to fix also it likes to try to die after any kind of hard acceleration ( anything harder than 1/3 throttle or more ) and am starting to wounder if they may be linked...any insight to this subject will be a great help. thanks a lot

mike

[nissanfanatic]

11.5:1 is what most street driven vehicles are tuned to. Its safe. You don't really pick up much power at all once you lean out past 11:1 and you begin to venture into dangerous lean areas once you go past 13:1. Tuning the fuel mixture isn't where you make power. Timing is where power is made.

[Black Lotus]

Is your car a Fiero?
Do you have a Design 1 turbo kit?

[fierojapan]

no the airforce would'nt let me take my fiero to japan with me so it's at home. right now i am messing around with my evo1.

so is it normal for a car to drop down to 11.1 when you hammer the throttle and then lean back out as you hold the throttle open?
right now i am not looking to through a lot of money into the car becouse i am getting ready to sell it. i can play with the base timing a little but i am not sure how much that will do. i am basicly looking to see what the stock ecu will do.

[nissanfanatic]

So.. is your car stock?

I'm not sure exactly how the car is tuned for the fuel you run over in Japan. From what I know its 100 octane. If its stock or bolt ons, then you are fine. Trust the factory.

[fierojapan]

ita got a couple of bolt ons. ARC intercooler, camshafts from an evo3 (they are a little beter than the evo1's but stilll a step down from a set of 262's ) boost controller, BOV, cat back exhaust, i am going to up the fuel pressure a little just to help cut the injector timing down a bit, and an apexi air filter.i have a couple other things i can do.

[nissanfanatic]

Try backing the boost down.

[fierojapan]

i got to talking to someone here and apperently what the stock computer is doing is right. it runs rich as soon as you step on the gas and then leans out as the computer adjusts the a/f ratio. it seems to do this verry well when running at .8 bar or 1.5 bar.

[KiwiBacon]

If it physically can't deliver the fuel, then it'll lean out under high boost and high revs.

Try either backing the boost off, or increasing the fuel pressure, if either helps then that's the problem.
If neither help, then your injectors might not be able to flow enough.

[fierojapan]

i think you missed my origional question. the car will lean out under boost when it is running at stock boost as well as averything else (.8, .9, 1.0, 1.1, 1.2, 1.3, 1.4, ect, ect,) as soon as you step on the gas it runs down to about 11:1 then it leans back out to 14:1 as you leave the gas on. i was asking if that was normal?

[KiwiBacon]

Originally Posted by fierojapan

i think you missed my origional question. the car will lean out under boost when it is running at stock boost as well as averything else (.8, .9, 1.0, 1.1, 1.2, 1.3, 1.4, ect, ect,) as soon as you step on the gas it runs down to about 11:1 then it leans back out to 14:1 as you leave the gas on. i was asking if that was normal?

Are the revs still climbing as it leans out?

It could be the engine control going open loop, then reverting back to closed loop once acceleration has reduced.

[nissanfanatic]

Is all your maintenance up to date? Fuel pump up to par, fuel filter, injector cleaning, MAFS cleaning if applicable, etc...??

[fierojapan]

well i now have a different delima to deal with. but to the other questions.

are the rev's still climming? yes, but it dosent start leaning out untill it comes close to the rev limit ( around 6000, redline is 7000. but the car consistently leans out at 6000 no mater what boost setting i have it set at, which is making me wounder if this is normal.)

is the regular matinance up? yes i run injector cleaner once or twice a year (depending on my mood), i replaced the fuel filter when i got the car last summer, timing is a little off (7 deg rather than 5) but not to far, fuel pump?????? it hasent ever given me a problem that makes me suspect the pump is going bad so i will say it is for now.


now my newest problem... i deploy it IRAQ at the end of the week.....so i guess i need to put this on hold for a bit.

i do appreciate the help and responses to my question. we will see how things are going when i get back with any good luck my wife will have the car sold before i get home. once again thank you for the help and hope everyone has a safe and fun summer...

mike