05 turbo mustang 3v lean tip in

[stangslayer]

I've been battling a lean spike condition resulting in 17-18 afr's sometimes backfiring for the past moth since installing this turbo kit. My maf is in a 3" pipe using a diablo mafia range extender to increase allow the stock maf to correctly read the increased air flow. I have scaled and rescaled my maf trasnfer function several times using 2 different methods and came up with the same x-fer each time so I'm pretty sure its in good shape. Its basicly scaled 1.59x over stock.

I've done alot of searching on this forum and other tuning forums and it seems this is a fairly common issue one newer model modified fords. 2 advised fixes that come up are 1) manifold volume and 2) transient fueling. I have tried both with no success. 1) My manifold volume stock is 10.9 liters. I tried 8 liters which did seem to help lessen the severity of the lean out but induced a lean/rich/lean/rich/lean/normal buck-surge.
2) transient fueling didnt seem to work as i interperetted it would. I played with all the tables sometimes scaling them 1.59x to match the amount my maf had changed or 1.2x. The table i put my hope is was under "acceleration" 'gain at start up'. Increases here did seem to help but as i increased these values my start up got so rich as to the point it would not start or run with afrs showing in the 10's if it did manage to chug itself to life.

Maybe my understanding of how to use the transient tables is misguided, but it seems like we are missing the parameter (accelerator pump shot) i need.

The car has a very slight lean tip in once its at operating temp but only bumps up to 15.5 for at most for a split second before maintaing a mid 14 afr. It is worst with a cold engine and gradually goes away as temps increase. any suggestions?

[fido]

Not 100% sure about that, but I solved two supercharged mustangs with the same problem by lowering manifold volume to 5-7 liters. I suspect it's somehow hardcoded and they derive "air transfer delay" in N/A application, but super/turbocharged ones are much faster. I also saw this problem in log, where MAF airflow did increase much quicker than calculated load from speed density. By lowering manifold volume it become much better.

[fatguy]

Ford uses the MAF for 85% of the engine operation. The other 15% is transient and the data comes from a table called "load with failed MAF" located directly under the MAF transfer table. This is the same table as the GM "Volumetric Efficiency". Datalog the RPM and Load when going into tip in, write a histogram to show where you need to make the changes. Also, if you are using this car more for racing than street driving, disable the Deceleration Cutoff so the engine doesn't lean out when closing the throttle. This is there to help save fuel, so if you do a lot of interstate driving, then I would leave it in as it will have a pretty big effect on economy. May not be a bad idea to set up a "road tune" and a "race tune".
Corey

[stangslayer]

I tried dropping the manifold volume as small as 5L but in my case it only changed a single 2 second long lean condition into a triple lean/rich/lean/rich/lean surge. I finally figured out how to log air load to configure my LWFM and that seems to have had the most effect. its a time consuming issue to trouble shoot becuase the engine can only stay cold for so long! lol. My most recent cold test drive still had a breif lean tip in my to 16.2 but that isnt enough to actually notice it while driving unless you have an eye on the gauge. I'll keep playing everything but i think properly filling in the LWFM was the fix. Shame on me, but because I had not figured out how to build my own histogram I had copied and pasted another members table since the setup was very similar. Just goes to show, if you want something done right, you've got to do it yourself (and not just because the other guy doesnt know what hes doing because it probably worked very well for him).

[foxsetup]

i know it's an old thread but i am actually having that exact same problems with my procharger set up. have you figured it out ?

[svtadam27]

Dial in your load with failed maf tables.

[Eric@HPTuners]

Enable Anticipation logic as well. Disabling it makes all sorts of tip in issues on these.

[stangslayer]

I haven't completely gotten rid of it yet but ive had other vehicles to keep me busy in the mean time. I was able to band aid it by extending the amount of time it took to enter closed loop at start up. most tunes enter CL from 5 to 60 seconds after start up but I lengthened that to 300 seconds since it seemed to be worse in open loop until it reached operating temp. Again, this was not a fix, but a band aid until i could wrap my head around the problem at a later date like today where i am rereading my old post to take another crack at it again.
Let me know if you find the cure.

[SultanHassanMasTuning]

give this a trymay 16 update_Test_old software.hpt