Had to see where your lean thought/comment came from, Found it.

I'd say it's a matter of opinion and that opinion may have jumped the gun somewhat. There is a learning curve to the Ford adaptive strategy. You can't throw a part on and expect the ECU to compensate right away. It will take a bit of time for it to relearn the new flow dynamics and adjust fuel/spark accordingly.

Initially, yes it will run lean. But putting an intake on will do the same thing, initially.
You've got a window of 25% + or - for fueling in the stock ECU. I see no reason to pay for a tune until all parts are put onto the car or you surpass needing 25% more fuel. Though I'm not saying by any stretch the stock ECU programming is the best for "racing". Driveability wise, it'll work just fine.

 

First adaptive learning should be turned off and for MANY reasons

Second what your talking about is Short Turm Fuel Trims , yes it can trim at idle and part throttle +/- 25%, It CANNOT change the WOT tables and thats where the problem is

I have dynoed about 45 ZX3 with installing the SVT header and ALL went lean and I have had to add as much as 12% WOT fuel

To say to install parts then get a tune now days is just silly and dangerous to your engine
I sell the xcal/predator with free updates as you add more mods why take a chance on loosing an engine or leaving power on the table till 4 to 6 months later adding your other parts

 

i didnt think the learning curve changed anything under WOT and that would be where you would cause the most damage from a lean condition. perhaps ive got it backwards but i seem to remember a local ford tech telling me that 2 or so years ago when i was BSing with him while we changed my fuel pump.
well, HE changed the fuel pump and i just watched and ran my mouth and tried to soak up anything he said and did like a sponge as i didnt know nearly as much about the focus back then. HA what am i talking about tho? ive already forgotten more than i know! [giddy]

 

my whole thought is. Yes, reset the kam after any engine modification. The pcm should learn the new value like you said + or - 25% before it sets a code.

a header is post combustion, and should not affect air/fuel ratio. It will scavage exhaust out of the cylinder better than stock. The maf calculates the incoming air charge. I just have a hard time believing that even in OL drive(WOT) that the stock fuel table is not adding the correct amount of fuel.

 

Sure a header will effect the AFR.

As with any engine when you increase the engines capacity for flow it has to effect the AFR (considering you can pick up between 15-20whp from just this mod alone) which makes this a substantial change. Even though the stock ECU is good it can only compensate so much... trust me I know the Zetec and SVT tune intimately at this point.

Now it may not lean out enough to throw a code or even cause audible detonation but it will be somewhat leaner than the factory setting.

 

i guess you aint so smart orange...how can a post combustion event affect afr.

 

For reference, at about 140WHP I was starting to run lean at WOT on the stock ECU and fuel system according to my wideband; and that works out to about a 25% increase in fuel demand.

 

Mine threw a code immediately when I installed it. It kept the code until I bought the tuner, now I'm running 12.9 (N/A) AFR and the car feels a lot better.

 

^Not even going to bother with you.



Tom, how does the programming work for WOT? Doesn't it have a preset O2 voltage to shoot for? and doesn't that voltage (very roughly) represent a target AFR?

I mean the ECU doesn't just dump fuel in and say 'there, that outta shut him up'. There is some degree of control over how much fuel goes in.

 

When WOT mode is used the o2 sensors are not used at all , they dont even need to be in the car when you go Open Loop, It is a set number (there are some small changes being made but they are little and would take hrs to go over and mean nothing in what were covering ) But mostly a SET lambda number for fuel in WOT OL mode , Yes its like here is X amount of fuel hope the engine can deal with it just like " here that outta shut him up" If not then make changes

Remember the way they "say" it "should" be done is set the target AF in the base fuel then trim with the MTF that alone tells you that the o2 isnt in the equasion for WOT OL fuel

Tom

 

Correct me if I'm wrong, but maybe to help understand... Aren't the WOT tables based on calculations using volumetric efficiences and a desired 'target' AFR. In essence, by knowing the VE of the 'stock' engine and the desired AFR the tables are calculated to provide a set amount of fuel which should result in the desired AFR at WOT.

 

That is more how the origional base fuel tables were set up yes , Once you change things , MAF , Inj , Boost , compression that changes as well

This started with the ECU adjusting the fuel tables and when in OL the ECU cannot

Tom

 

OK. well until i have the money for a tune, Am I going to cause any damage to the engine?

 

I dont know , Whats your air fuel reading ? Till you can answer that I wouldnt go WOT

Tom

 

Stay out of WOT

 

Are the OL tables related in any way to the CL tables?
Meaning that if a mod is done and the MAFS consistently reads more air and adds fuel to match, does that alter the VE of the engine that the OL tables would use?

 

I'm sure Tom will jump in and help on aswering this, but, I'll give it a crack.
The tables are for the most part all based on open loop, meaning everything that is being done is based on fixed values and volumetric efficiences of the engine to calculate fuel requirements. Closed loop is when the ECU is using O2 sensor input to fine tune fuel delivery. I don't believe there are separate closed loop tables, just ol tables that are modified with cl info. Tom, way off or not?

 

Sorry to be "dense", but what does WOT stand for. Maybe after knowing this, I'll know what you are talking about.

Just to throw it out there, my ZX3 has the SVT header and cat, but I have no CEL and has passed emissions. So am I running lean on my ZX3??

 

Emissions is a different story altogether. They only look for pending codes and conduct testing at idle and in some states steady part throttle. I don't know of any state that does Wide Open Throttle testing or testing up to redline.
So basically just because you passed emissions might not mean you are running rich or lean. You really have no way to know other than using a Wide Band Oxygen Sensor or doing an actual dyno at a shop.

I can see where I am because I have a Wideband and I also have logging software for my car and the Wideband.

 

WOT=Wide Open Throttle

 

Also, remember the tables are a very defined set of values and parameters. Modifications that cause the engine to perform outside of those parameters is a recipe for disaster.

 

i don't know if somebody already said this or if this is true in a focus. but, increasing exhaust velocity means that you are "sucking" more combustion gases out of each cylinder. i know that gm uses valve timing to leave some of the gases in the cylinder to decrease NOx. if all of the gases are out of the cylinder more air can be added in place. there for more fuel is needed creating the lean condition. please correct me if i am wrong

 

Your right, you have better scavenging (pulls more spent exhaust gases out) and it allow for more unburnt fuel/air to come into the cylinder.

Gee its AMAZING how something done to the exhaust can effect the AFR... some people [rolleyes]... not aimed at you alex.

 

but are you talking about running WOT say in 5th gear or for svt 6th??? or WOT running through all the gears, mashing the pedal down for all 5-6 gears to get the lean. Its not good to WOT through your higher gears, so that leads me to believe you're talkin about WOT at your lowest gear 5 or 6. right?
(note: may have flopped the higher gear, lower gear terminology, hopefully you know what i mean if i did.)

 

what does gear have to do with volumetric efficiency?

 

I'm getting a lean code p2195 with my new header mod. This code seams to point towards an O2 sticking lean. Is this typical or am I fighting a bad new O2 sensor?

 

Let's get him a new thread^

What header? Shorty or long? Change/install the header gasket (properly)?

 

Code could be
bad o2
vac leak
wiring
installed wrong o2 as front o2

What does your wideband air fuel gauge show at idle ? do you have a xcal to datalog with ?

Tom

 

I'm sorry Svt header swap. Aftermarket Cat back exhaust. Stock cat with stock flex pipe (stupid but hopefully not permanent). K and n filter. Manual Trans. Unfortunately I do not have a tuner or data logger yet. I read mixed reviews about the swap causing an actual code. While I understand I may be running lean and I'm definitely leaving power on the table. I'm low on funds and need to pass smog.( a friend can look past mods as long as there is no code). The front O2 is a question in my mind only because it was a mail order part. It was listed as a Bosch replacement for the vehicle and was replaced when the swap was done because the last one backed out of the old manifold and rattled around for a while. It should be fine but I'm not an expert. I'm aware that this code is not the general lean code where the computer can not compensate. It reads as sensor sticks lean. So I am asking if someone has gotten a code after this swap and what code is it?

 

I am guessing you have fixed the EGR code you would get???

that's usually the only code I have heard getting after the conversion.

Do a quick check of vacuum lines and get a new O2 sensor. was is a Bosch sensor or was it something else? try going to the junk yard and see if any of the junk yard cars still have down stream O2 sensors and grab one and swap it out. Also how did you do the cable extensions to the new SVT bung locations? perhaps you used to small of a awg of wire and are having voltage drop in the cable.

 

Either way you should deffinetly get a tune.

 

I welded in new bungs on the upstream and downstream O2 sensors. The factory wiring was previously repaired by me with a ford replacement connector and wires. This has proven solid for a few thousand miles and gave me some extra room to work but with the O2 mounted in the header collector it probably would have worked anyway. I also routed the downstream wiring to the back of the engine near the firewall and didn't have to splice it. I tied the egr into the header and it runs through the obd monitor test without a problem. It is a Bosch O2.