Hey guys need your expertise- I just had Jan flash my car after doing head,cam,550 inj etc.- when I went to get on the dyno it showed it was running VERY lean- jan tried a few programs but said there must be something wrong with the fuel system as i was not getting enough fuel
Any ideas?? Do I need to run different fuel regulator??- thanks in advance for all your help=

 

I'd be wondering if the fuel filter is real dirty or if the fuel pump has the correct pressure.

 

I was thinking the fuel filter but only 25,000 miles on the car??

 

Well with 25,000 I find it hard to believe the filter would be bad. So much for a simple fix... Guess the next thing to do is have the fuel pump tested to see if the pressure is up to snuff.

 

Fuel pressure would be my guess. If everything is checking out on the software side then your left with a few things:

-Not enough fuel pressure. The first place to look is your fuel pump.
-Faulty injectors. Not likely but possible
-faulty 02 sensor. Always a possibility, but if it was working fine on other cars that likely is not the cause.

 

What are the exact specs on your car?

 

OK update- I had a thumper head, ns1 cam, mynes headers, mynes 550cc inj. done at the same time- I also have the borla race exhaust, m7 intercooler, alta CIA- 15% and 2% pulleys- I sent the ECU to mynes to flash - It was running lean upon return- So since mynes locks the ecu so u can not make changes I had him set it back to normal and had Jan send me one of his remote tools-After jan flashed it a few times it still shows VERY lean on the dyno-AFR about 14 when I was told it should be around 11-
I did a pressure test and got around 4 bars( about 60 psi) consistantly-
I hooked upa OBD2 monitor and showed zero codes-
My plugs are dry and white-
Not exactly sure what it could be but def. need ideas - thanks(sorry for the long winded write up)

 

Get your fuel pressure regulator checked. Could be a weak spring.

 

If it was the reg. I do not think it would have been holding pressure so strongly??

 

I am going to check the headers to see if the O2 sensor is off or loose of bad???

 

Where have you been pulling your AFRs from? Are you using a tail pipe sniffer or something bolted in on the header? Have you tried changing either one of those?

 

Is this occurring on all cylinders?

 

Great question. If you use a tail pipe sniffer it will definitely show lean due to going thru both cats.

 

It came from the tail pipe- but my plugs are dry and white??- this is very frustrating and i am open to any ideas=thanks
one of my techs( I work for Ferrari) suggested that I get a wide band o2 sensor to make it easier to read????
Also I have the mynes header- we put the car on a lift and noticed that the o2 sensor at the cat had a large spacer on it and my tech thought that the spacer would pull the o2 sensor away from the stream therefore giving it a lean read- We removed the spacer and put the O2 sensor back in so it is in the stream- Will see if that makes a difference-

thank you for all your help guys I really do not know what to do at this stage!!!

 

Or tap your stock #1 sensor and get a better idea what the computer is seeing.

 

I think you may be talking about the post cat O2? If so leave that spacer or else you may through a code. That O2 has nothing to do with the AF mixture.
If you have not done a thorough fuel pressure test then do so. Do so on a dyno if you can, or at least run up the RPMs.

Gotta start there.

 

Ooops, see that you did do this?

Not sure 60 PSI with 550s is enough. ??
Do you have the graph?

 

It's really hard to diagnose something like this without knowing what was actually done during the tuning session.

At what speed did you measure the fuel pressure? If you did at idle but not at WOT at high RPM then your diagnosis is incomplete. If you arent getting enough fuel pressure for some reason that is where it is most likely to manifest.

If you measured from the tailpipe are you sure you have no exhaust leaks? That could certainly throw a reading off.

 

thanks - Idid not do it at WOT but pretty close- I will try it again- thanks so much - I truly appreciate all the advice!!

 

No code..... No limp mode... 550s - no tune should be rich.... big letters RICH

What kind of injectors??? low or high impedance?
You have 60 lbs at the rail
White plugs
Tail pipe = black? Some soot?
Does it nose over as you get close to red line?

Do you have some JCW 380s you could use for a day?

An old school tail pipe sniffer would tell you something, otherwise you may have discovered "how to run big injectors & run leaner than OE".

To rule out the fuel system or injector, compare OE injector ( temp at the upstream O2 ) with the 550s - you can see this with most scanners....

 

You said it right there. Normal plug color is a grayish brown. You definitely have a fuel problem.

 

How does the car idle?
Maybe a intake leak somewhere?
Do you have a boost gage?

 

+1

42-key in pos 2/52-idle/62-high RPM's at Idle - are psi's at my fuel rail.

If all those things have panned out, I get a sense you may have modded beyond the perfomance specs of the stock fuel pump and stock FPR.

 

The fuel pump and filter are rarely the problem. It can happen, but it's rare.

Some posts have questioned whether your testing methods are giving you true results (if you car is actually running lean). White plugs and lean conditions at the tailpipe is irrefutable evidence that you have a problem. The AFRs from a tailpipe sensor will be no more than .5 ratio difference from the upstream O2 sensor: it will not 'show lean' because it's been through the cats.

I like the suggestion to go to some factory injectors and see if that solves your problem. Except for extreme tuning projects, 550cc injectors are very big: you could be running into scaling issues.

 

Gary.........get down to Helix and have Eric check this out. I thought you were going there right away?