autox19

I am running a JDM b16a OBD0 engine with OBD1 Dizzy and ECU chipped running crome 02 is currently disabled, ELD is currently disabled. in a fiat X19 with rywire race harness. (no chassis harness hook ups) I am having an issue when I turn on my cooling fans, the A/F runs really lean. It wsas mentioned in another thread it might be my "dead times". I am trying to find out more information on what this is and how to adjust it in crome. I am googling and finding quite a bit about "you need to adjust your dead times to X" but nothing really on what it is or where to adjust it in crome.

Odie
B16 Fiat X19.

2x0

Basically dead times (or latency) is the amount of time it takes the injectors to fully open after they get the signal from the ecu. This will vary based on voltage, so when electrical load is applied such as a cooling fan turning on, it could decrease operating voltage which results in the injector dead time increasing. The ecu must compensate by sending a longer electrical pulse to account for the variance in dead times at different voltages.

I don't know what injectors you are running, but usually new aftermarket ones will come with a list of dead times. Or they can be measured after the fact when you send them to someone who services injectors, such as FIC.

autox19

great simple answer! that makes it far more easy to understand than what I have found! Injectors are stock and I have them set as such in crome. I am also changing the fans out as they are 1979 inefficient beasts sucking up over 30 amps. so hoping to keep the operating voltages up. FYI, I will shoot a video tonight showing what I see. I will still have the current fans until this weekend.

Odie
B16 fiat x19

2x0

Unless crome has somehow loaded incorrect dead times, it seems unlikely they'd be off with the stock injectors. I am no pro when it comes to electrical, but I wonder if the fans are causing some other interference that is throwing off your sensor readings or something. Do you have your ecu logic ground and wideband grounded securely to the thermostat housing or some other source?

motoxxxman

I agree with this.

Aside from entering pre-determined latency tables, the best way to adjust them correctly is:
1) with engine at full operating temp (driven for at least 20 minutes), adjust idle afr in the fual map with all electrical accessories shut off, and fans not running.
2) unplug the alternator (the plug, not the power cable). voltage will drop to battery voltage. Adjust the latency value in the ~12v cell (if voltage is close to 12v) up or down until afr is the same as in step 1 above with fans and all electrical accessories off.
3) with alt still unplugged, turn all accessories on; radio, heater fan on high, headlights on, interior lights on, etc. If baatt voltage is around 10 volts, adjust the latency value in the 10v cell up or down until afr is same as step one. if voltage is not down to 10v yet, wait for fans to kick on, and adjust it while fans are running.

Dead times should now be set correctly. The key to getting it set correctly though is to make sure the coolant temp and air temp is the same for all 3 steps. If coolant temp or air temp is different between steps, the temp compensations will start to alter fueling as well, which can screw everything up if they aren't set perfectly too.

autox19

Fixed!!!! The old fans were screwing it up. Too much draw, interference which knows. But I bought 2 new ones and poof all looks well


odie
b16 fiat x19

2x0