03/04 LEAN Down Low...

[orange2004cobra]

Everywhere I see a dyno sheet {not my own as of yet on my 04} I see crazy lean cond down low on the 03 o4 cobras..
I can only assume that it is coused by fords use of the new Dual Pattern Injector that is on the 03 04's.
They did this for emmissions..
i also understand that with the dual pattern injectors, it is a programming issue as wel, and if thats the case, you cant merely retrofit standard injectors and have them work perfectly. I am sure you can make them work {many are right now} but the diff. in programming in inj. pulses etc, has to have some effect on the retro injectors..
Does anyone know if anyone is playing around with the stock inj. setup and trying to overide the "emmissions" mode on the 03/04 program..?
Lin

 

[caveman6666]

Yeah, it bothers me too, though I never thought of it as an injector issue.

 

[mike_b_svt]

Off Topic...

Ok, I know this has nothing to do with your question, but I don't suppose you could post a picture of you car?

I have yet to see a pic of an Orange Cobra!

Thanks,

 

[JDV]

Yes, even after the predator program, they are too lean for my taste around 3k rpm.

It looked to me like trandfer from closed to open loop wasnt happening fast enough. I never thought of it like that. On old carburated blower cars, wed up the accelerator pump to fix that (the transition from idle circuts to WOT venturies).

Mine was pinging in that range after i put the pully on it, even iwth the predator pulley tune.

I had Johnny Lightning write a tune, and asked him to richen that area up some, and lean out the top end. Problem solved. No more pinging, much better curve down low, and smooth up top.

You can still see that it looks lean down low but now its just the time it takes the computer to get fully into open loop mode and get that rich. Pinging is gone now, thank goodness.

Sorry for the pic quality, but i dont have scanner. Had to shoot it with Digi Cam.

 

[PhillyCobra]

Lean condition at low RPM is programmed in stock ECM. Tuners can flatten it with chip or reprogram of ECM. Don't think it's because of newer injectors.

Also, be aware that one reason program is lean down low is that on boosted engine, you get a huge gulp of air when you open the throttle quickly and generate boost, which causes a compensatory burst of fuel to prevent detonation (like an accelerator pump on a carb). Have seen dynos on tuned cars that show huge drop in A/F (to 10) when throttle is opened at low revs after the leaness was tuned out.

 

[SNKBITE]

Just have your tuner fatten it up from 1800 to 4000 rpm like I did.
Any good tuner can do it.

 

[orange2004cobra]

Actually, i havent seen a tune yet that will effectivelt richen up the bottom rpms on these cars.
13.1 or higher is the norm even after tune..
And I understand your statement about richening up after boost, but how many people see boost all the time driving around town?
2to 4k is where most street cars live at until they are run hard, and it just seems to me that its hard on them to run that lean..
And there IS a direct link between the new injectors/program with the 03/04 models and leanness down low..
You can read more about it in Sean Hyland new book...{awesome I might add...}Lin

 

[NetworkingGuru]

I have the stock tune, and My A/F is lean until 3K or so, even when opening the throttle at 1.5K. However, there is zero detonation from it. I DID have minor detonation (inaudible, but confirmed visually on the plugs with a magnifying glass) with the stock plugs at the stock gap, but since going to AGSF12's gapped at .038, no detonation (I check my plugs RELIGEOUSLY).

18K like that. I don't really worry about it anymore. I just keep an eye on my plugs.

 

[vetkilr]

Re: Off Topic...

Originally posted by mike_b_svt
Ok, I know this has nothing to do with your question, but I don't suppose you could post a picture of you car?

I have yet to see a pic of an Orange Cobra!

Thanks,

Here you go!
Its mine:

http://www.fnsweet.com/forums/showthread.php3?s=&threadid=12806

 

[vetkilr]

Another things guys is most A/F meters dont read low rpm A/Fs good.
The velocity isnt great enough thus they are reading the air in the pipe which will be lean.
Once the rpms get up and the velosity is good it reads better and closer to real conditions.

A shop did a comparision between a A/F reading in the front o2 sensor and then reran it at the tailpipe and the tailpipe reading was leaner at low rpms then was identical at 4000rpms up to the o2 reading.
Velocity does play a part in A/F readings.......period.
So if it is reading a littel lean at lower rpms it more than likely is richer than it looks and safe!