Step 1 of 3
by Michael Decipha Ponthieux
This page ONLY applies to those whom were directed here AFTER receiving a custom tune from me.
Last Updated: 2020-10-14
DO NOT, continue reading this page until AFTER you have read over and verified the Pre-Tune Information and
Initial Tune Instructions
If you have a quarterhorse you must use TunerPro RT. If you don't have it setup yet the Getting Started Write Up will give you all the details.
Subscribe to your Tune Progress Thread
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Load Tune & Verify Tune Loaded Correctly
First and foremost load in your startup tune before doing anything.
Make sure you ALWAYS VERIFY that your tune is for you, the first letter will be the initial of your first name.
For example: MPON_191014a.bin. ----> M for Michael PON for Ponthieux, _YYMMDD and the revision for that day a,b,c,d,e,f,etc...
When receiving your tune verify it is for you. If the tune is not for you then DO NOT LOAD IT.
If using an SCT handheld then CLICK HERE for the SCT Information link with specifics on getting the SCT device and livelink configured correctly.
Once you have your tune loaded and turn the key on you will hear the fuel pump prime and shut off.
IF THE FUEL PUMP DOES NOT SHUT OFF THEN THE TUNE IS CORRUPT, DO NOT TRY TO START THE ENGINE.
Then set the base fuel pressure to either what we discussed (typically 55psi if you have less than 60lb injectors).
Next verify the ignition timing is at 10 degrees btdc with the spout plug removed. This is VERY IMPORTANT otherwise you risk damaging the engine.
|For EEC-Vs that have been converted from returnless to return style, the fuel pump may run constantly with the key on unless I have written
custom code and remapped an unused output pin to control the fuel pump correctly.
In all cases, verify the ecu is communicating correctly by starting the log with the key on / engine off and pumping the throttle a few times to verify the
dashboard gauge shows throttle movement before starting the vehicle.
When you load the tune in and fire up the engine for the first time on the startup tune it most likely WILL NOT BE HAPPY.
You will need to do EVERYTHING you can to baby the engine and keep it running until it gets in to closed loop and corrects fueling.
Don't worry about how the engine starts cold or idles since it cannot be adjusted until after the warm engine fueling and idle is dialed in.
Cold enrichment compensation and startup compensation can ONLY be adjusted AFTER the base fuel, idle spark, throttle stop and idle air has been dialed in correctly.
If the engine doesn't fire up on the first crank, repeat a 2nd time, if it doesn't fire up on the second crank, then HOLD THE THROTTLE TO FLOOR == WOT to
enable flood-clear mode. On all factory ecu's this will shut off the injectors during cranking. The ecu is pre-programmed to disable the injectors when the pedal is held
at WOT during cranking to clear out and engine flood.
Note that flooding the engine out with excessive cranking can wash down the rings and destroy an engine. Although all decipha tunes incorporate excessive cranking fail-safes to
prevent this occurrence it is not practical to do excessive cranking. If you cannot get the engine to fire off post the log for review and a revised startup tune.
DO NOT do any of the following with your startup tune:
- > DO NOT go racing.
- > DO NOT go WOT.
- > DO NOT spray nitrous.
- > DO NOT do any burn outs.
- > DO NOT do any quick throttle stabs, smooth and slow pedal movements only.
- > DO NOT drive the vehicle across country until after step 1 is completed.
Verify its not overly rich
If you have a wideband watch the gauge and make sure it is LEANER than 0.82 lambda after the engine has been running for at least 2 minutes, if you don't have a gauge then
pay attention to the hegos. IEGO1 voltage should be reading less than 0.800 volts after the engine has been running for at least 2 minutes. If the hego voltage is stuck above 0.400 volts
and is not switching (jumping above and below 0.400 volts) then the engine is rich. Shut the engine off and post the log to your private thread for review and an updated tune.
Note: If you feel up to it, you can reduce the maf flow at 400 imaf counts on down by multiplying the flow by 0.85 this will remove 15% fuel and expedite the process.
As always, whenever you have EDITED your tune be sure to post your modified tune along with the datalog you created using it.
Don't be worried if the wideband reads lean at idle. Its safer to be leaner than richer below half throttle. Ideally we want it at 1.000 lambda but if it idles at 1.23 lambda
thats perfectly fine as well and will not cause any harm so do not be alarmed. A lean mix can only harm the engine when your at or greater than half throttle. Below half throttle
being lean is perfectly fine and cannot hurt anything.
WARNING: The check engine light should not be on while tuning! If the check engine light comes on at any time while the engine is
running then SHUT THE ENGINE OFF IMMEDIATELY and pull codes. The check engine light will only be illuminated on a tuned engine when the ecu has detected a MAJOR PROBLEM
that could potentially cause catastrophic engine damage. If the check engine light comes on at any time while the engine is running immediately shut the engine off and pull codes.
Note: The CEL will be on at key-on while the engine is not running and will turn off during cranking as-is normal operation signifying the ecu is powered up and the engine is not running.
Once the engine gets up to warm operating temperature it should go into closed loop and adjust fueling.
If for any reason it doesn't you may need to rev the throttle a few times in order to get the hegos to switch and allow closed loop.
The OL/CL indicator on the dash will inform you when you are in open or closed loop. You can also easily tell if your in closed loop by LAMBSE jump up and down increasing and decreasing its value.
if LAMBSE stays at a single locked value then you are in open loop.
Warm Stable Idle
Once the engine reaches a operating temperature approximately 15 minutes of running, let it idle on its own (if it can).
If the engine is capable of idling on its own let it idle for at least 75 seconds with the engine at a stable warm idle with no throttle input.
During this time I highly recommend checking for any coolant, oil, powersteering, or any other leaks underneath the vehicle.
Pop the hood and make sure nothing has come loose. Give everything a good double over as you will need to drive it. Double check the brakes and lug nuts are intact and that the
brake fluid reservoir isn't empty. Continue to
LEAVE the datalog recording and proceed to do the following.
Idle in Drive for Automatic Electronic Controlled Transmissions (94+ only)
If you have a 94+ ecu with an electronically controlled automatic transmission or if I've written custom code to differentiate drive and park;
Stop the and save the log. Shut the engine off and wait approx. 20 seconds then restart the engine.
Immediately put the vehicle in drive while holding the brake. Include a 5 minute datalog of it idling in gear.
Do not move the vehicle or take your foot off the brake. We need this to dial in the isc drive multiplier (airflow in gear) and if the vehicle
moves the air correction cannot be calculated.
Once this is completed (If applicable) proceed as follows.
Remember, the engine has to reach a warm stable idle (not surging) before dialing in fuel otherwise the datalog is useless.
If the vehicle has been sitting a while or if you hadn't put fresh fuel in the tank recently then now is the time to do so. Your first trip should be to the gas station to fill up with fresh premium fuel
(low grade fuel can only be used if discussed and the tune is setup for it). Now that you have fresh fuel drive to a nearby patch of road you and your comrades use for testing and tuning.
Most of you will know what im talkin' bout! Go ahead and cruise on out there to perform the step 2 log. If you don't have an area you play around in you can drive on the highway where you have a
straight patch that you can safely do some testing.
Logging for Fuel Errors
- The engine should still be running now but if for any reason you had to shut the engine off DO NOT FIRE IT UP AND IMMEDIATELY PERFORM THE FOLLOWING STEPS!!!!
Anytime an engine is restarted when at operating temp it takes approx. 2 minutes for friction and puddling affects to clear out and allow the engine to stabilize
completely before any fueling corrections or tune adjustments can be made.
You must now drive the vehicle to hit each imaf or mapope point for fueling corrections. This can be done on a non-busy street or in your own driveway if its lengthy.
If needed you can ride the brake to load the engine and prevent excessive speed. Partially setting the e-brake can make this task significantly easier, safer and faster to do.
- Watch the IMAF (maf voltage ad counts) on the dashboard and use the throttle pedal to hold the imaf at each +25 ad count increment.
If you are idling at less than 175 imaf ad counts, lightly tap and hold the throttle until the imaf reaches the next +25 imaf increment ( either 175 counts, 200 counts, 225 counts) and
HOLD it there steady for at least 10 seconds.
If you have a speed density ecu then look on the dashboard at MAPOPE and try to maintain it through out the rpm range from idle up to
For example: you will need to modulate the throttle to maintain .40 mapope from idle rpm all the way up to shift rpm (6k rpm or so).
- For Mass Air - slightly apply a little more throttle and hold it at at the next +25 imaf ad counts increment (ex: 225 cts), again for at least 10 seconds.
For speed density ecu's come to a stop and repeat again holding it at the next +0.05 mapope Ex: 0.45 from idle up to shift rpm as best as you can.
- Repeat these steps again for at least 10 seconds at the next +25 cts imaf increment (ex: 250 cts), hold it for at least 10 seconds.
- Repeat this in +25 ad count intervals going as high up the IMAF (or mapope for speed density) as you safely can or feel comfortable doing. This can be a tedious process
for a first timer and may take several iterations to reach all of the imaf or mapope points.
- Continue until you have to apply half throttle to maintain a specific imaf point or have reached 0.85 mapope. DO NOT EXCEED HALF THROTTLE.
For mass-air, ideally it would be best if you can reach the highest imaf that corresponds to the rpm you will spin the engine up to. For example: do not exceed 6k rpm to reach
any higher imaf points if you will not be running your engine over 6k rpm. After you have reached the highest imaf point you feel comfortable reaching, let the engine return
to a stable idle for at least 30 seconds before stopping and saving the log.
Half Throttle / 0 vac / 0 boost PERLOAD
After completing the above imaf or mapope increments you will need to do an idle to shift rpm HALF throttle pull for PERLOAD calculations.
If you have a boosted setup its imperative that you try to maintain 0 vac and 0 boost as closely as you can through-out the rpm range.
NOTE THAT THIS IS NOT A WOT PULL. DO NOT EXCEED HALF THROTTLE FOR ANY REASON.
With the engine idling on the road pointing in the direction you plan on going quickly HOLD half throttle until you get to your shift rpm (6k or so).
Let the vehicle coast back down to speed in order to pull over safely to stop and save the log.
- If you have a manual trans its best to use 2nd gear
- If you have an auto trans you must lock 2nd gear by putting the shifter in 2nd. if you cannot manually place it in 2nd then 1st gear will do.
If you have a glide then use 1st gear obviously.
Post the logs in your Private Tune Progress Thread.
After I review the datalogs I'll post back with an updated revised tune with specific instructions to proceed.
DO NOT Continue to Step 2 until you are specifically instructed to do so.
Understanding the Step 1 Changes - FYI
I usually start all my custom tunes from my base tunes, I then typically apply the following changes for starters.
|Base Fuel Table||I null ==1.000 so interpolated lambses don't skew my corrections
|WOT Multiplier||assign all 1500+ rpm to wot lambda (just in case someone goes WOT its not commanding lean)
|FN320A||I max it out so open loop is forced only by tprel while i dial it in since fn035 won't be dialed in yet
|WOT Breakpoint||I kick it up along with the OL breakpoint scalar so i can see how the fuel trims up top
|Hego Min Switches||I set it to 1 switch so it goes into closed loop quickly
|BYPLES||I kick it up to 60 sec for initial tuning so the hegos have 60 sec to fail if the fuel is too far out and it can't switch in a shorter period of time
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