So I know that the question has been asked before, with the differences between the F23A1 vs. the F23A4 only being the valve cover and exhaust manifold supposedly. The deal is, after driving over an hour to pick up the F23A1 that the junk yard told me they had, it turned out to be the A5(non vtec). Not wanting to leave the yard empty handed, I took the A4 they had, since they claimed it would work. I just wanted to confirm this and find out what exactly I would have to swap from the blown A1 motor.

 

Dude... What car is this going in? All yo have in your sig are cars that have been junked, sold, chopped in half? Get rid of that and just jot down what you currently own.

Most likely you'll need the ECU since that engine is the ULEV. I just bought a replacement A4 for mine last night

 

A4 is ULEV, along with a different cylinder head, it also uses a wideband O2 sensor and a 32-bit ECU, so get those if you didn't.

 

IIRC, theres also substantial differences in the cars wiring harnesses.

 

Here a article from Honda stating the differences

http://www.hondanews.com/search/rele...in&s=honda

think the cylinder heads are the same.

 

Thanks HondaRacer4Vtec, that was a great link. I bolted the engine in last night into my buddies 99EX. It all seemed the same, short of the valve cover, exhaust manifold, and a few random sensors which I was able to swap.

 

Let us know how it works when it's all hooked up and running.

 

Well, it starts. It is running real bad so far. I did not have time to really troubleshoot it last night. Pretty sure it is a sensor issue. It idles fair. As soon as you give it gas it dies. If you give it gas slowly you can get it to about 2.5k rpm before it cuts out. All the sensors on the Intake Manifold and TB are the same. How do you reset the computer?

 

Disconnect the battery or pull the ecu fuse for 10 seconds.

Make sure the A4 is running the 32-bit A4 ECU and has the A4 wideband O2 sensor in the manifold.

 

According to the link posted by HondaRacer4Vtec, it seems that the A4 is the same engine, with the only differences being bolt ons such as the exhaust mainfold. I used the exhaust manifold from the A1 which was stock in the car, and made sure that all the sensors were the same on the intake manifold and throttle body and used the injectors from the A1, so everything should be running according to A1 specs.

I was just reading the specs in the Honda media newsroom and it says "The ULEV engine uses a rotary air-control valve that also controls the Air-Assist Injection system, in place of the electric air-control valve and fast-idle valve used in the previous Accord." Maybe that is the issue. I checked all the sensors and they had the same part numbers on them and everything between the 2 engines. I guess I will check again.