I'm much better with jets and needles and carbs :sweatdrop: I'm new to tuning with a computer, so go easy. Should I have been adjusting the injector offset in the box with FV next to it? I'd normally ask these questions on the eCtune forum but it seems pretty dead these days. Any insight? Also, the AFR's are jumping around a lot, between about 13.5:1 and 16:1. I ended up having my Overall fuel trim set at 93% to have my car idle at about 14.0:1 which is where it seemed to like aka wasn't having an occasional misfire every few seconds. When fully warm I tweaked it a little further. I wanted to be safe while the car warmed up. Is that true? Do they do the same thing? It was still lean, so I increased and increased. It seemed that whenever I clicked the + button it did the same thing as entering the value with my number pad. The car was idling super lean, so I began to entered 15% manually in the Overall fuel trim box, because I didn't want to click the + button 15 times. Should I put it back to the DSM 3 ohms? Anyway, not the main question here. Started the car again, and it was idling less rough, so I left it at that. I thought I remembered hearing somewhere that the injectors were actually 2 ohm, so I switched to DENSO 550cc 2 ohm.
Injector cranking primer enrichment evom install#
Used the various tutorials for injector seal modification for DSM injectors, and used this tutorial for making my plug and play resistor box harness: Complete DIY Plug and Play OBD2 Civic Resistor Box Write-up EJ6 EJ7 EJ8 EM1 EG1 EG2 EH6 - Honda-Tech Car is OBD2a -> OBD1, running eCtune w/Demon.Īfter the install I opened did key on engine off, and changed the injector calibration as follows - Old Injector: 240cc, New Injector: 560cc, overall fuel trim 0%, Battery Offset: DSM 95-99 450cc, 3 ohm. I usually just divide them in half and the car starts stock smooth again with no spark plug fouling.Just installed stock EVO 560cc injectors. I’ve been able to run as high as 560cc injectors EVO injectors without really needing to tweak these tables but when you start getting to the 720cc range, you might want to start reducing the base values a bit. Must be left over from the earlier days before they wired up the starter system to the ECU. The ECU knows when you have the key turned into the START position. One last table the ECU uses is just a simple RPM look up to tell if the motor is actually running on it’s own power or still being spun by the starter. Just after the engine has started, there is also a milisecond timer counting down and another enrichment factor is applied based on coolant temperature again (shown in the above screen shot). This is why you piggy back guy running HUGE injectors may be having start issues. (Base Primer Pulse + Adder value) * RPM Comp / Ignition stroke reduction = Start up IPWĪgain the fuel table, injector size and latency tables are completely ignored while the engine is in “cranking mode”.
The formula from start to finish is this:
So as the starter is now cranking the motor, the ECU now counts how many ignition strokes the motor is turning and then starts reducing the Corrected Primer Pulse. There are 2 other compensations still to go! So we have the Primer Pulse * RPM Correction Factor = Corrected Primer Pulse. In a future chrome ROM, I might make use of this for an alcohol switchable map. The coolant temp switch value between these two tables is -4 degF so again…. As you can see, both tables are the same so coolant temp is irrelevant. There are two tables and coolant temp determines which tables is used. First one is a multiplier which is looked up based on how fast your starter is cranking the motor. As you can see, the cooler the coolant temps, the longer the injectors are held open.Īfter this primer pulse is setup, there are various corrections which are applied to it. The value comes from from a table which I’ve dubbed “Cranking IPW ” and then there is an Adder value applied, then this Primer pulse sent to the injectors. Once the engine first starts rotating from the starter, there is a single injector pulse that is calculated. The ECU simply calculates an IPW based on a few factors. As it turns out the fuel table, injector size and latency tables are completely ignored during this time.
I believe the answer to the issue with “hot starts” on some cars can be fixed in here. Turns out, there’s quite a bit going on when you turn the key. 90% of you probably won’t ever need to modify these tables but I was curious how the start up routine worked in the ECU.