milanoteggy

iTrader: (2)

hey have a 200whp gsr and recently there was a dyno day at pointzero (my engine builders) and we put my car on the dyno to see how its doing, the owner of the dyno stoped my car at around 7k because he said it was running super lean like mid to high 14's, tony the tiger tuned my car in feb and everything was fine,car sat in my garage till april then after driving around for a month and a half i thought the car was slower , did a compression and leakdown test with good numbers so i figured maybe i was getting used to the car, but the dyno showed there is def something wrong, i emailed tony and he said to check my fuel pump, fuel pump wiring and fuel filter, im getting an oem fuel filter tomorrow and i have a brand new walbro fuel pump so i dont think thats the problem when i turn the key i hear it prime, i have brand new rc440cc injectors but im going to get them flow tested and maybe see if ones not working, also going to do sparkplugs just because i have some, both dynos were dynapacs, if anyone ever had a problem like this please let me know
thank you

94VTEC2TONE

definetely check your fuel pressure under load if you can, myabe your running out of fuel.

SL0WEGG

What kinda gas are you using?

milanoteggy

iTrader: (2)

ultra 94 highest grade you can get here in canada (pump)

mouab18c1

iTrader: (5)

Thread jack, but your not as lean as mine. At WOT in vtec I lean out to 18 or so. Basically hitting a brick wall. New Walbro 255 fuel pump and rc 310's as well.

Did your tuner add more fuel?

PyroProblem

Check your alternator output also. If you have a voltmeter, check voltage at the pump then take it for a spin paying special attention at higher rpms...

milanoteggy

iTrader: (2)

ive read some things about if the alternator is going it wont send the right volts to your injectors but wouldnt my battery light flash? and no wont bring it back to tony until i can do as much as i can to solve the problem myself, buts thats really high my a/f start going lean once vtec hits and gets worse as the rpms increase too

DDTECH

This can happen as voltage to the injectors increase or decrease their open and close times will change as well.

Because voltage varies from car to car, most tuning programs will include whats called a "injector offset" table, which will help you show what voltage is needed for which injectors to properly run @ Max performance.

Climate change might have something to do with it as well. If its "that" lean in the upper rpms, i'd just have it retuned.

milanoteggy

iTrader: (2)

it was negative 17 when i got it tuned that day dont know what that is in fahrenheit but it was +28 on dyno day i think 82.4Fahrenheit, it was tuned on ectune aswell , so you think i should just go for a retune and see how it goes? or should i get the injectors flow tested

PyroProblem

It very well could just be the IAT correction tables may be off just a little...

If you really want to diagnose the "tune", try this...

Get you a 10k-15k ohm resistor (radio shack) and plug it into your IAT connector. This tricks the ecu into thinking its alot colder outside than it really is... Take it for a drive and see if it still goes lean. If AF's look normal, you probably just need your tuner adjust the IAT correction tables...
Good luck.

milanoteggy

iTrader: (2)

ok thanks alot for the help im going to do that today and ill post results

milanoteggy

iTrader: (2)

the weather was a bit cooler today and wasnt running as lean always on WOT would never go past 13 in the video it hits 13.5 and 13.6 which is better than yesterday becauase it hit 14's , so i think im going to do fuel filter spark plugs test the injectors and go for a retune hopefully that will fix everything, video is in 3rd from 3000 rpm sorry for it being shakey but u can see the a/r still

http://www.youtube.com/watch?v=KZfmoptBnic

igorka_91

iTrader: (1)

IMO that two month old gas. Is your problem.

PyroProblem

I think a touch up on the IAT correction tables should do the trick.

SL0WEGG

This is what it appears to be.

mouab18c1

iTrader: (5)

Here is a screen shot of my datalog just so you get the idea. Running way lean in. I'm starting to think it's an electrical problem since the car runs perfectly fine besides this.

Tony the Tiger

Just touched base with the OP through email, but anyhow, if the IAT compensation is off, it will cause the car to run lean across the entire scale.

As explained, because the engine was leaning out after 7000RPM, that cannot be the IAT comp because it is just a fuel multiplier across the entire RPM scale... It can't change the fuel curve, so it either runs lean across the board, or it's on the spot. A sudden lean spot, especially up top indicates a fuel delivery problem, or battery voltage problem. But I always have the habit of adding slower response times as voltage drops anyway, because I rather let the car run rich than lean if a mishap occurs (like an alternator belt flying off during a pull, etc...).

I won't suggest re-tuning it.. That's putting a bandaid to the problem, and you could never predict when the fuel system falls behind again. Especially if the issue is aged fuel pump wiring, poor ground connections, failing pump or a bad regulator that's causing fuel pressure to drop (more likely if the fuel heats up from hotter weather). It's a false sense of security to think the car is running fine after some ECU tweaking, just to see it lean out again as the fuel issue gets worse and could end up melting the motor.

mouab18c1

iTrader: (5)

Fuel pressure regulator can cause the fuel to lean out?

PyroProblem

Good info Tony.
Perhaps you have a failing pump? Wasnt there some Walbro
fakies being sold not too long ago?

mouab18c1

iTrader: (5)

I don't know about the OP but I have switched from my stock pump to the Walbro 255 and same results. Two pumps cannot go bad. And according to Tony's post, I knew I was right that it was not my tuning that was causing the problem as I was thinking exactly what he stated.

milanoteggy

iTrader: (2)

so i changed my spark plugs, fuel filter and all my grounds, car goes lean in vtec still but the car idled lower after :s next step is to test the injectors. mouab18c1 any luck with your issue?

PyroProblem

Have you tried this yet?

When you replaced your plugs, did they all look pretty similar?

milanoteggy

iTrader: (2)

damn thats what i forgot to do was check the alternator, and yes all the plugs were the exact same

milanoteggy

iTrader: (2)

how do you check the voltage at the pump while driving?

PyroProblem

Either a 2nd person (preferably)
or
a voltmeter with long leads and putting the display directly in the line of sight as your driving.
(I do not recommend this since its a safety HAZARD and you could crash and die).