Thread: DET swap only runs with USDM DE ECU

I just finished doing a DET swap (I was told bluebird, but I think it's an Avenir engine, how do I check?). Car cranks but I have no spark with the DET ECU, or G20 ECU (donor car that the DET was in).

Car fires right up with the DE ECU (even with the JDM MAF), and has nice hot spark. Car will idle if there is enough leaks after the MAF. If all the leaks are plugged, plugs get fouled up and the engine dies.

Is the ignition wiring different between the two? Also, with both the G20 and DET ECU, the fuel pump won't prime. I am running the 93 DE harness from my car as the G20 was so cut up it was scary!

I thought the swap was bolt in and the harnesses were the same. Is that not the case? Mechanically, the engine fit like tight glove, so tight in fact I need to come up with something for my MAF and air filter.

Seems like injectors fire with both ECUs (I start smelling fuel after a while of cranking and not starting). Will verify with a noid light tomorrow.

Any ideas?

using the de ecu u need to use all de sensors, switch over the sensors and use the de ecu, what distributor are you using? i believe you need to change that also at least i did. use the de TPS... what do you mean leaks after the maf? your maf should not be plugged up thats why it is dieing on you...

I'd like to use the DET ECU so that I don't have to get the other one reflashed (the car is my DD and I don't have the time to wait).

All the sensors and distributor are from the JDM motor. It's weird that the DE ECU even starts it I guess.

By leaks after the MAF, if I induce leaks, like the BOV or other piping, the car will idle on it's own (if you can call 2k RPM an idle). As soon as I seal everything up, it dies, as it should, as then it is running much too rich (no leaks after the MAF that the ECU doesn't see). I'm using the USDM harness and O2 sensor (which I doubt is wired differently). I want to use the JDM ECU (which is what the motor came with and all the block sensors are).

Does anyone know of a way to check for bad ECUs? Can a dealership do it? What's with the diagnostics knob on the back?

Make sure the ECU is seated firmly and evenly in the harness. Also make sure you plug in the connector in the center console. Its about half way up on the inside of the pass side behind the hvac controls and I think its yellow. If you don't get that one the fuel pump won't prime.

All of that is fine. I can literally swap between ECUs and one works and the other two don't. I've been doing everything through the drivers side access hole, and I've made sure the connector is fully tightened on the end.

With the USDM ECU, as soon as I flick the key to on, the fuel pump primes. I haven't heard the fuel pump prime with the other two. It seems that a relay clicks twice with the other 2 ECUs but only once with the DE one. It's the gold one above the power steering pump.

Found it.
Both the G20 ECU and the DET one had 2 burnt traces. I have a feeling that the MAF wiring in the G20 had shorted out as that trace and the ECU ignition power trace were both burned.

Re-routed the trace with some 24 gauge solid wire and car now runs with the DET ECU.
Just gotta bolt up the exhaust and BOV recirc and I'm done mechanically!
I can't wait to drive it!

enjoy!