I'm am stuck on deciding which engine management system I'm going to get, I'm leaning toward the Hondata with an OBD-II adapter harness but I was told there are holes in the system when dealing with OBD-II. Does anyone have any experience with the AEM EMS or the Hondata. Pros and cons of each system for their car?

 

For the AEM EMS system, do a search in the FI forum, many members have tried them out. Initially, the AEM EMS system had its flaws but only for cars like the supra, so nothing to worry about there.

The only advantage I see that the Hondata system has over AEM is the price, which is really determined on what your plans are for your engine.

If you are going to stay N/A to Hondata 2 would be just fine for your application, because you won't need to constantly change the settings of your ECU. Several of the bad things about Hondata is that fact that it only works with a OBD-1 ECU, which means you not only need to get an adapter harness for an OBD-2 ECU, but you have the OBD2-series 2 ECU, equiped on 99-00 Civics. This is harder to find that just the 96-98 adapter harnesses and more expensive too, which is a huge hassle. The other thing is the Hondata is not a "true" standalone system despite what kind of bs you hear on this site, therefore you may find yourself wanting a wideband 02 later on down the road. In addition, when you finally get the Hondata, you will need to get it tuned by a professional and get someone to burn the chip that is provided with Hondata everytime you want to change the 3 fuel map settings. But, this would be cost effective if you were just going to run N/A.

The advantage of the AEM first and foremost is that it is a "true" standalone system alowing you to control EVERY aspect of the ECU, which replaces your old ECU so no need to spend an extra 150+ on an ECU plus 100+ on a conversion harness. The AEM can be tuned once by a professional and then "tweaked" every time you change the charateristics of your engine, which happens frequently when you are using any type of FI. The only disadvantages are the price, which I've seen as low as 1100 and as high 1400. this makes it far more expensive that the Hondata, but it is worth every penny depending on what your plans are for your engine. The only other thing I think of is the yearly emissions checks. The diagnostic checks that are used during your state inspection will not recognize any CEL codes when hooked up to the ECU AEM provides you. To my knowledge the AEM system does not have CEL codes. But, if you check their website I am sure you will be able to find ways to get around it.

 

EMS is just so much nicer, so many more options and it is designed for obd2 but to some it might be a little overkill.

 

Not really a hassle. I have the harnesses in stock. Same price as the version1 harnesses(96-98). Price is 170 shipped. Guaranteed to be the lowest price. All harnesses you Brand New OEM pieces with full warranty.