Bought a 2007 RX8 with a bad motor for my stepson and we pulled the bad motor and put a used import one in that had good compression.

It came with an ECU but emmediatly was in immobilizer mode when we hooked the battery up. Tried a few things from the internet and they didn't work. So we put the old ECU back in. It took it out of the immobilizer mode. It cranked a few times, started, and then died. Cranked it over and couldn't get it to start. You could smell the fuel. So went through the process to clear flooded engine and it would fire back up for 1-2 seconds and die. Again it appeared to be flooded again. I tried to give it gas as it started and it did not react at all or stay running any longer.

I did notice the ecu's had different numbers but they were both for the same engine and transmission setup.

I tried a new MAF and it did not help. I have not hooked up the catback because it was cut off. The upstream o2 is hooked up but there is no downstream o2 hooked up.

We have double checked all the vacuum lines and their placement. I currently have no scanner or code reader and would be interested in suggestions. Kind of reminds me of a temp sensor reading -60 and flooding it with fuel at start.

 

You need to use the ECU that was in the car.

It is likely really flooded now. If it is an MT the best is to pull start it

Did you reset the ESS when you installed the new motor? It will need to relearn the shaft profile.

Make sure that you hooked up the injectors correctly. Did you check/change the ignition components?

 

We did not do the ess reset as I didn't know what that was until now. Noobie mistake. Almost all electrical was left intact and as in on the import motor. Was nearly completely plug and play.

So far it has easily fired up and hit about 1200 rpms after going through the steps to clear a flooded motor. Plan was to get it running and change out spark plugs and wires afterwards.

 

It's very easy to mix up the primary and secondary injectors when installing the motor, which will cause issues like this.

What killed the first engine? Make sure that thing isn't still on the car: ignition coils, clogged catalytic converter, cooling problems.

 

After tearing the old engine down we found that the bolts on the front end of the e shaft had gotten loose and worked out to where they were they had almost ground off the ends on the cover in front of them. It was so loose that it caused the front bearing to look spun and tore the teeth on the stationary gear and front rotor.. Is not common from what I have read.

 

Just to help anybody else out that may have this problem, I figured out what my problem was. I did figure out I had a bad throttle body but the real colprait was I had the battery charger/trickle charger on. Soon as I tried it without it it started up. Spent two weeks trying to run down a problem I was causing.