Ok, so I brought my 04 RX8 as a project car for $800 and it came with an engine with broken seals but was able to turn on nevertheless. After I brought the car I was finally able to buy a decent used engine with 80k miles from JDM on Ebay. After take super extra care to make sure everything was connected as i put the engine in, I got the car ready to be started. I got to start the car with the ECU that came with the engine and it did nothing. I took that ecu out and put the one that came with the car back in and the start started spinning the flywheel but that's it, the car doesnt even sound like it wants to start just start spinning the flywheel. I though well it not getting a spark, so I put the coil pack and wires from the low compression engine on the new/used engine and I also took out the spark plugs and checked them. So, after that I went back to start it and got the same thing. Now, Im stuck, idk what else to do. Also, i think the spark plug housing on the engine is stripped.

 

The ECU you got with the engine didn't work because the immobilizer in it needs to be programmed to work with your key cylinder.

Is the engine you got the same as the one that was in the car before? In other words if you had a 6-port manual before, do you have a 6-port manual engine now? Many of these JDM resellers confuse 4-port and 6-port engines. Do you have some info from them to confirm this engine has good compression?

Other possibilities: the ignition coils aren't connected to the correct spark plugs, the injectors are not connected correctly (common mistake), the eccentric shaft position sensor is not connected, the engine is flooded. Is there fuel on the spark plugs when you take them out? Look up 'deflood procedure' and see if that gets you anywhere.

I suggest hooking up an OBD2 reader and watching the rpm, airflow and other available data to see if anything looks out of place. If the eccentric shaft sensor is disconnected, for example, your RPM will read zero.

 

-Could the ecu not matching the engine be the reason for it not starting?
-I was thinking bad compression as well but JDM had a compression video on the engine, also im not sure if its a 4port or 6 port (will it matter?)
-On the coil pack the spark plug wires only reach a specific length, also i put them back the exact way they came off (Ill double check to make sure though)
-When installed the engine the engine still had everything on I just had to take of the intake manifold to install the engine. (so in theory wouldn't everything connection be connected in its respective place already?)
-And I can find my OBD2 reader, gonna have to get one in a few. (im taking a break right now)

 

Ok, I put the OBD2 meter on the car and its giving a code for lost communication with ECM, would that be the reason for not starting?

 

Use your ECU. Check all the connections for the coils and wires and injectors etc against a wiring diagram.

Check all the fuses....

If the intake manifold doesn't look like the old one...you have the wrong engine and you won't get it running. Odds are that unless you have a 2004 or 2005 automatic...or bought an engine from one...that you have a 6 port and you will be fine

Why do you think your spark plug threads are stripped?

 

Yes.....check the fuses in the inside fuse panel...there is one you likely blew for the ECU/OBD port. Cn't remember which one it is...but the car won't start with it blown

 

Also, I been trying the deflood procedure all day. I took the spark plugs out and tried to start it while stepping on the brakes and then reinstalled the plugs then tried to start and nothing. When I took the plugs out originally there was a gas/oil mixture on the plugs and that mixture shot out when I then the procedure.

 

Its an automatic 4port. and the only difference in the intake manifold was the oil cap other then that it was the same completely. Also, i believe the spark plug housing is stripped because when trying to reinstall the plugs its very tight like im going to break it and one of them i had to extend pass the wheel well and use a bar lever to get it out and it was still hard to remove.

 

Just check all the fuses and they all checked out. Before this engine from edm the old engine with low compression was working. It idled and everything.

 

If the plugs came out with aluminum on them you may be in trouble.....if they thread in and tighten OK you are OK. Lots of times the carbon on the plugs makes them difficult to get out.

ALWAYS put a bit of NeverSeize on the threads when you reinstall them and tighten them carefully...start them threading them in by hand until they get tight and use a socket to tighten them up....

Before you try anything else confirm the plug wiring.... Did you change out the injectors or coils between the engines? Otherwise the wires go Leading front/ trailing front/ leading rear/ trailing rear...front to back off the coil pack. If you didn't change out the injector wiring you should be OK with that... And with only 4 injectors it is a lot more difficult to mix them up

If that all checks out and you think you are flooded...take out the plugs...and disconnect the shft sensor. Turn over the motor till you quit getting crap blowing out of the plug holes.
At that point clean off the plugs or swap in a new set if the are sketchy at all. Reconnect the shaft sensor and try and start it.....if it doesn't start put your foot to the floor n crank it until it burps or tries to start...and then release the pedal and try and feather it to keep it running

Once you get it running go and drive it around to clean all the gunk out

Hopefully you have an engine with decent compression...because if you don't you will have issues getting it to start

 

The only connector that is not connected (Not sure if this would stop it from starting) but the 2nd O2 sensor located on the muffler is the only this not connected. I triple checked every connection before the engine when went in the car and as I was installed it. I was super careful. I dont get why she wont start .

 

Did you reset the shaft sensor profile? ( key on brake pedal taps until the oil gauge sweeps)

Are the injectors and coils off the new motor or your old one?

 

I never touched the injectors. And the coils are off the old motor. And yes I did the 20 brake pedal stomps for reset. Is there a way to check for spark coming from the spark plug wire?

 

I thinking its either a bad engine or the engine is flooded. But im not sure, because ive tried the flooding methods (there are many of them) and I saw the JDM compression test videos (they got good reviews from people and youtubers) so im pretty sure the video is trust worthy.

 

You can buy a spark tester.

 

how does that work? And could i just put the spark plug to the wire where some gloves while someone starts the car?

 

Using the spark plugs is not as reliable as the tester.
The HEI Spark Tester (The Best Spark Tester On the Market)

 

It could be responsible, yes. What was the actual code? Are there any other codes? Is there any sensor data while you try to start the car? Have you used OBD2 tools before?


Stepping on the gas. You want to be stepping on the gas all the way to the floor for the deflood procedure. This cuts fuel delivery. Did you clean/dry off the plugs before putting them back in? If you've taken them out a second time, after the deflood attempts, do they have gas/oil on them again?

Basically what you need to determine which of the following is missing: fuel, air, compression or spark.

Spark you can get via the tester posted above or other types of testers. You said you're using the old engine's coils. That engine died for a reason, and coils are a really common one. So make sure they work, and plan to put fresh ones on there unless you want to replace the engine again.

Compression you need to measure yourself or see what info the seller can give you. It's possible the engine they sold you is toast. What numbers did it show in the video?

Fuel, like I said, people have messed up the injector wiring when replacing engines, which can have unpredictable results. Review your wiring.

Also, how old is the gas you're trying to start this car with? If it has been sitting for a long time, you may need to add fresh gas.

 

The gas is about 3 months old, and NEW DEVELOPMENT! I had my gf try to start while i investigated. There is smoke coming out the muffler as she attempted to start it. Does this confirms the engine is flooded?