Startup Enrichment
Startup Enrichment is the additional fuel needed to stabilize the engine for every startup, better known as a "Choke" in carburetor's. If you haven't dialed in base fuel yet then you can't dial in startup enrichment yet. Once your base fuel is dialed in for startup fueling compensation you have to dial in the startup enrichment "lambse subtractor" table.Also note the other big contributor to startup is dialing in the isc multiplier table(s) fn1861 / fn1862n / fn1862d.
This is covered in the
Cold / Startup Enrichment Write Up
Resetting the ECU / KAM Memory
Once your fuel has been dialed in, the KAM memory will not need to be reset.It is NOT recommended to reset the KAM memory for any purposes, the adaptive memory can ONLY benefit the tune.
An unintentional memory reset such as a loss of battery power will not warrant any tune adjustments.
If the vehicle has been sitting for an extended amount of time without the engine ran, so long as the injectors and MAF
sensor remain the same as it was when tuned, no tune adjustments are required.
Keep Alive Memory SHOULD ONLY be reset when fuel modeling has been changed
this will occur under the following conditions:
- MAF Transfer Function adjustments greater than 5%
- Injector High Slope adjustments greater than 0.5 lbs/min
- Sarchg (CID - Engine Size) adjustments greater than 50 cubic inches
Adjustments made to LAMBSE in the fuel tables WILL NOT require KAM to be reset.
to reset KAM's do any of the following:
- The easiest method is to change the kam clear scalar to clear then hit update, then change it back to normal and hit update again, key must be on
- OR... you can select an empty tune slot with the key on then select back to the tune
for example, (if using BE) open up hardware >> moates config >> select tune slot 7 which should be blank, the pump will run, then select tune slot 8 again and the pump will shut off (if thats where you have your tune written) - OR... or you can write a corrupt tune to it like a CBAZA tune to a GUFB ecu for example
- OR... you can disconnect the battery for 30 minutes
Retuning Required
Retuning is required under any of the following circumstances
- MAF sensor changes - all changes must be made in the MAF transfer ONLY
- Fuel Injector changes - all changes must be made in the injector parameters ONLY
- Fuel Pressure changes - all changes must be made in the injector parameters ONLY
- Cylinder Head Replacement - spark table and peak load function must be updated
- Camshaft Replacement - dashpot MAY need to be updated
- Base Timing changes - Ignition timing (spark table) and injector timing must be updated
- Fuel Grade changes, ex: E-85 or 87 Octane - AFR parameter and/or spark table must be updated
Tuning Fuel Blind - No Fueling Feedback
In some cases you will run in to some vehicles that do not cooperate. In these instances often the hegos are non-functional and an aftermarket wideband sensor either isn't possible due to the setup or just non-functional or reading incorrectly. In most instances it is due to burning oil and/or cam timing events or large exhaust with poor velocity. In any case in order to dial in these setups you must return to the old school carburetor style methods of dialing in fuel by feel. This is my method that works for me.First you will have to force open loop which goes without saying if you have incorrect or no hego feedback. Force OL Then simply go play with the maf transfer to get the engine running as best as you can. Without having any way to read the afr you cannot dial your fuel in so you have to tune it like a carb and adjust the maf transfer to see if the engine likes it or not. The best way to do this is to get the engine up to operating temp then at idle go adjust the maf flow at that imaf ct your idling at by reducing the flow multiplying it by 0.95 and updating. Continue to reduce the flow in 5% intervals until the engine starts dropping rpm and you will also see IPSIBR starts shooting up to add air to maintain idle. You have now reached the lean best idle fuel. Now multiply the flow by 1.05% to give it back 5% to make her happy again. At this point you've now reached the leanest point the engine will happily idle at and you've dialed in that maf point. Now use the throttle to reach the next imaf ct point and start over again. Dial in each point as well as you can until you reach the highest imaf cts point possible. Then to dial in those higher points you have to drive the vehicle. Hold the maf stable at that next imaf while driving and dial it in. Keep repeating until you reach half throttle. After half throttle it is safer to add fuel in 10% intervals by multiplying the flow at that imaf point and all the points above it by 1.10 until you've reached the point where adding fuel seems to slow the engine down or make it not as responsive. At that point remove 5% and your at the richest best fuel point for enrichment fuel and WOT. This is a tedious process so be patient. If a dyno is not available and street tuning is required its always best to have someone ride with you if possible to make operating the vehicle and tuning safer and easier.
Summary
In summary, The ONLY methods of ADDING MORE FUEL is by either INCREASING the MAF flow, REDUCING INJECTOR SLOPE(S), or by REDUCING THE STOICH VALUE.Even with known values fuel is seldom dialed in hence the need for custom tuning. Typically with known data its usual to be lean on the big end at WOT. Usually the mid-range is fairly close and idle will almost always need adjustment regardless.
If PRLDSW=0 and FN035 is scaled properly as per the Scaling Write Up your fuel table should be set as follows:
NOTES:
if you input the actual flow values for your injectors from a flow bench as well as the maf values from the flow bench your fuel will probably be off a tad, it should be perfect in a perfect world but we don't live there. A flow bench has nothing to do with injectors or a curve or anything, a flow bench just measures flow, a good starting point but thats it Free reving an engine to dial in the maf meter is a very valid and effective means of creating the curve down low, you can typically dial it in enough to drive it out of state This is maf not speed density, the maf measures airflow, it doesn't matter if your engine is at 2v on the maf at a steady 60mph cruise or if its at 2v on the maf free reving at 4500 rpm. Its still flowing the same amount of air, a non lab-spec wideband is not as accurate as a narrowband at finding stoich, a narrowband ONLY measures stoich You can't use them to dial in fuel for anything other than stoich, however, you can should always use the narrowbands to verify the wideband is accurate If the narrowband voltage isn't over 0.8 volts at WOT then it would be wise to start snooping around and questioning the wideband could also be a faulty hego ground (check out Hego for more details).actually get effected by rpm but its very minute, this is exactly why you can't convert from a breakpoint scalar to function
LOAD
Load controls spark, load is calculated by the MAF (airmass) and SARCHG (engine size "CID") load is ford's equivalent to VE (volumetric efficiency). A bone stock E7 headed SBF 5.0L 302ci should reach a maximum peak load of ~78 at approximately 4k rpm, with LOAD reducing above and below peak tq.Thus, SARCHG on mass air ecu's is primarily used for spark control being that the major influence is LOAD. SARCHG has no direct affect on fueling for mass air ecu's. Changing the load value will not enrich or enlean the mix directly. However, changing SARCHG will change LOAD, and that could cause you to be in a different load cell causing enrichment or lean out if the above minimum changes required aren't adjusted to compensate.
Continue reading on to Startup Enrichment Write Up.
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