bouckarooo

Well, the usdm crank pulley/sprocket and the balance shaft one is different than the jdm obd1 engine, so in order to get everything to work in correct function(as i had to change the oil pump also<this for the cps> it was recomended by honda(alberta Honda was the dealership i consulted) to use the usdm pulleys. As for the intake manifold, well this had to do with the type of injectors that are mounted on that manifold(there is another reason also and i will go in to that in a bit). First, the injectors on the 4th gen are what is known as peak and hold injectors, which incidently are a better performing injector; the h22a4's utilize what is known as a saturated injector. Now heres the reason behind the logic of this part swap, the ecu of the h22a4 is not able to run using the peak and hold style of injector(unless you have an added ecu managment system like hondata, chrome, aem ems, and the like), by trying to use a 4th gen injector with the 5th gen ecu you will fry out your ecu as the current needed to run the peak and hold type is greater than the saturated type and the usdm ecu is only programmed to operate the lower current requirement of the saturated type; you can however use the saturated type as a direct replacement for the peak and hold type as they require less current and the ecu is capable of delivering the current amount it needs(the 4th gen ecu will send ,<lets say just to make it easy...these aren't the actual numbers, i am just using them as example to make it easier to explain> 10 amps of current to the peak and hold type, and the peak and hold type needs all 10 of these amps to operate; so then the 5th gen ecu delivers only 7 amps as the saturated style only requires 7amps; herin lies the problem, you can use the saturated on the 10 amp ecu as it will only draw a maximum of 7 amps; however once you try and use the peak and hold at 10 amps on the 7amp ecu it will fry your ecu as it is trying to draw the 10 amps of current and it cannot). The second reason i had to use the manifold is becuase the usdm ecu is obdII and therefore requires the use of the Emissions Gas Recirculation Sytem(E.G.R, i am sure you have read about cleaning these ports to clear errant CEL's), so in order to maintain the obdII on the car i had to switch the whole manifold, seeing how i needed to use the injectors also it only makes sense to do so. Also there was another reason, however this one is easy to get around, especially if you have a good freind at the local Honda dealership, there is wiring differences all through out the engine bay and it seemed as if many of the elctrical connectors were a diffrent style on the jdm engine than the usdm one, you can buy the right connector then just switch them but i found it easier to just swap the parts over;it is more reliable this way also as there is less chance of error or failure as you are not modifying the stock part to make it work(many call this kind of thing a "hackjob", however it is sometimes neccessary, but i do try and avoid it where i can if i can). I am sure you know about the oil pump issues and the dizzy issues so i will not go into them as you did not ask but they are also a neccessity to perform a correct swap.