im lookin for someone in the N.Dallas area that is pretty savoy w/ turbo cars, FMUs, Injectors, etc. to try to help me figure out whats goin on w/ my car. for starters.....i took apart the FMU and it looks fine. the problem is when i go into boost my **** goes lean. real lean. but when i let off to 0% throttle it goes rich for like 1.5sec. someone help.

 

FMU = fuel management unit?


are you venting to atmosphere with the blow off valve? and what type of air flow sensor are you using? it sounds like your not making any corrections at all with fuel, and running off of a stock non-turbo tune. if you have a map sensor on the car stock it will be a 1 bar map sensor which will peg at 0psi boost, and anything over that will read the same, so you will run super lean. of your running MAF type sensors, then it just depends on how much airflow they are capable of reading. if your just simulating it with bolt ons, then i will be no help. and if your running a MAF sensor with a VTA BOV, then you will always run super rich when you let off the throttle unless your able to tune the TPS compesation with some sort of standalone.

 

running a 2g DSM BOV(recirc). its the RRM setup that uses a Vortech FMU (12:1) and Walbro 255. i seem to be the only car that is expeiring this problem that i have. when i put a new FMU on it worked fine for about a 1.5weeks(took apart the FMU and everything looked fine). then started doing this again.( it did this before when i living in WA.) using the stock MAF sensor. im goin to pull (stock) inejectors on wendsday. if i cant find the problem im mainly lookin for a local shop/ person who is savoy in turbo kits etc. that might have an idea to what could be causing this.

 

does the 2G BOV use a diaphram or a metal valve? i seem to recall the 1G is the only one with the metal valve, but i never did anything with the eclipse series. also if your using the stock injectors and reaching 100% duty cycle, or really over 90% your going to run lean up top. your not flowing enough fuel and there is no more room for compensation by adding duty. you can run some basic numbers online through various calculators, but check what massflow you need for the HP you expect with your setup. and then lookup how much the stock injectors will flow. if your close, time for an upgrade. if you want to see what kind of cone the injectors are spraying, it is simple (well relatively speaking...) you can do it a few ways, the first is to remove the fuel rail with injectors from the head (leave the fuel lines and injector wires connected). next, put some glass jars over each injector, have someone watch the glass jars as you turn the car over very briefly. you should observe each injector spraying a nice cone shape. if you suspect an injector is not flowing right, try backwashing it. you can apply 12V across the terminals to open the silonoid from any 12V battery, and you can flush the injector out backwards. i do this the "jerry rigged" way by simply spraying MEK into the injector backwards once it is open. if there is something clogging it you will see it come out the back. make sure when you do this your as sterile as possible because you don't want stuff coming back into the injector. i'm sure there are backwashing kits available somewhere. i highly doubt there is anything clogging your injectors so i wouldn't even waste my time checking. if anything you have reached 100% duty cycle by boosting your car, and the stock fuel system isn't keeping up (sure the pump can pump enough, but your only as strong as your weakest link. last thing to check would be the FPR. not sure if you use a rising rate fuel pressure regulator, but they work on the idea that when manifold pressure increases, they increase the fuel pressure for more fuel, and possibly it's not compensating for increased manifold pressure because of the turbo.

next how much do you understand about the wideband readings? how much is really lean to you? and how much is really rich? are you reading lambda or A/F? why type of sensor is it and what is the latency of it? how quickly does the display you have refresh? or are you logging it to a laptop and plotting all the points. typically the displays will cycle at a frequency of that less then the sensor is reading at, just so you can read the display. if you log it to a laptop with RPM and manifold pressure you will get a much better idea of your A/F ratios. next how are you determining your ratios? are you doing 4th gear pulls on the highway or something? or are you just running from a stop in first gear? dyno maybe?

but really, what do i know? obviously not enough about the bolt on world, because i'm not familiar with a FMU. i have tuned with a S-AFC2 before if that is considered a FMU (and i laugh at how completely rediculous it is to pay that much for how little it actually does), but by far i preffer full stand alone. why dick around with bolt on and fooling the stock computer into doing what you want it to do, when for 900 dollars you can get a complete stand alone engine management system, make your own wiring harness, and pick your own sensors.

 

ok. well. not sure on the 2g BOV. the RRM Turbo kit is designed to run stock injectors at 7psi.( i seem to be the only one with the problem i have). as for the wideband i have a PLX M300 refresh rate is Accurate Air/Fuel Ratio <0.1, Fast Reaction. digtal display (http://www.plxdevices.com/M-Series_productinfo.htm) 2nd lean for me under boost is 14AFR casue my EGT starts to go over 800cel. super lean witch is what its doin now is like 18-20AFR. when i swaped FMUs on the car is ran 11.5-12AFR for about a week then stoped. i took apart the current FMU and it looks fine. doest matter what gear i pull in it goes lean like **** i can feel the engine bog....if i were to do a 4th gear pull 100% throt. i would probly just detonate and blow up my motor. i am currenty trying to save to get a Link ECU+injectors but i kinda want to know what the problem is (ex. something majorly f*cked up) before i spend $1300 to try and fix it. if ur goin to Evo meet tommorw night ill be ther and show u my setup and gauges etc.

edit: i can also hold the boost at 0psi and my AFR will drop to 12

 

if you have a digital multimeter you should test your MAF sensor. if your not reading the airflow properly, obviously it will never know to correct and run super lean. testing it with a multimeter shouldn't be to hard. there will be specs for the resistances somewhere on the internet or in the shop manuals.

the amount your running lean is a pretty serious problem. what connects to this FMU you keep speaking of? are you splicing into the airflow signal wire? if so check your connections there. in fact, any place you did wiring, check the connections. intermitant connections always cause problems that are extremely hard to diagnose.

and no i wont be at the evo meeting. i have formula car meetings on tuesday and wednesday evenings.