I’m using the PNP harness for my EMU black (piggy back setup) on my built and boosted 99 Lexus gs300. My question is, when using this PNP harness, is the fuel and ignition completely taken over by the EMU Black or does it just modify the signals sent by the stock ECU? Because if that is the case, that would mean you can’t bypass the fuel cut or ignition cut strategies the stock ECU uses for the rev limiter (in my case, 6500 RPM) and overrun if using the PNP harness.
I still have the stock transmission, controlled by the stock ECU and the ETCS-I throttle body. I wanted to convert to the Dodo racing COP kit and run sequential ignition instead of the stock wasted spark. I was getting spark blow out on the dyno with 9lbs of boost and stock wasted spark set up. I guess these stock coils are notoriously bad? Needing to bypass the stock igniter by implementing an IGF signal simulator to not get any CELs and connecting the COP harness to the emu directly instead of through the PNP harness. Same idea with the fuel injectors, not using the PNP harness and directly going to the EMU black to totally bypass the stock ECUs rev limiter as it implements that by cutting fuel or so I understand, and setting my own rev limiter strategies via the EMU black.
Can anyone help me out with maybe understanding of what I’m saying would work or if I’m making sense? Thank you!
The EMU black can’t modify signals. It is a standalone ECU that controls spark, fuel, boost, etc based on it’s own tables. As you are using a PNP harness configured for wasted spark, you most likely need to run new wires for the COP.
Please also check if your PNP harness is supporting a cam sensor. The EMU needs both crank and cam signals to run sequential.
Spark blow sometimes also occurs due to incorrect coil dwell settings. How did you configure the dwell on the EMU black?
I will Still be using the PnP harness for the cam and crank sensors that are wired through it to the EMU black and stock ECU.
Why I ask the question about the overrun and rev limiter strategies still being controlled by the stock ECU is I was hitting the 6500rpm wall that comes from factory even with a tune on the dyno. There were no fuel cut strategies or ignition cut strategies in place on the tune (yet). But was still hitting that rev limit so I assumed the stock ECU was implementing its factory strategies.
I’m hoping with better coils (dodo racing COP kit) that it will help with better spark. Not sure if I will run into any problems having fuel and COP kit wired straight to the EMU instead of through the harness.
With your PNP harness I expect the EMU black to control spark & fuel, so the original ECU can’t use those. Do you have a DBW controlled by the original ECU? In the EMU datalog you may spot the TPS dropping down near rev limit.
Overrun is normally controlled with fuel cut (and a bit of spark advance/retard for smoothness or noise). So I would expect it is controlled by the EMU Black via your PNP harnass.
To revisit a question I raised earlier. How did you configure your Dwell settings for your wasted spark coils? Would be a waste to spend money on COP if the wasted spark coil is good enough with sufficient dwell.
As far as I know, the dwell settings were the same as what came with the base map I used, I didn’t change them and I believe through V3 on the EMU black there are also correction tables based on MAP but main table I believe is based on battery voltage.
The DBW is not controlled by EMU. It is controlled by stock ECU, DBW throttle also controls automatic transmission so that’s why it’s still in place and not replaced by a FFIM. From everything I have read, the stock ECU implements fuel cutting for the rev limiter. I haven’t found or read anything about the DBW being involved in this instance.
I wanted better coils anyways, hence why I’m upgrading them, and these specific ones still fit under the stock TB which goes over the top of the engine (YUCK!)
According to this pinout your 6 injectors and 3 coils are directly connected to the EMU black. The stock ecu has no control over fuel and spark anymore. So it cannot rev limit.
In the pinout I see that ignition output 4, 5 and 6 are not used. With some additional wirering you can connect those to use the 6 seperate COP. Some modification in the EMU Software is needed as well