ecu

[vincenity_23]

with everything stock..would a new ecu..can you tell a difference in power? or with more torque? might be a dumb question but might as well ask.

[sonikaccord]

No. As long as the ecu is specific to the engine, you wouldn't notice a difference.

[Fleetw00d]

There were updates to ECUs along the way, although as soniaccord indicated, you probably wouldn't notice it, a newer one might improve performance/economy a little. I just swapped a 37820-PT6-A52 (from a 93 EX coupe auto) in place of the 37820-PT6-L51(shown as superseded on Majestic's site) in my 92 EX coupe before driving it to TX. I haven't specifically calculated the fuel economy, but I believe it is a little better than with the old ECU. I did the swap primarily to see if idle speed would drop; I couldn't find a good reason for fully warmed up idle to run at 1000 rpm even with base idle set correctly. With the new ECU, it dropped to about 800.

[GhostAccord]

Thing you have to remember about these cars is that they are old. Sensors get dirty and don't read quite as accurately as when they were new.

In my opinion, you could probably see more gains from swapping out or cleaning all the PGM.FI sensors than you would upgrading to a new version of the same ECU.

Only Honda knows why they made a new version. May or may not have had anything to do with performance or fuel economy. Could have been because they started using a different chip set or capacitors on the main board??????

[deevergote]

The ECU is programmed for a specific engine design. Until you drastically alter the engine, the ECU that the Honda engineers designed will be the most effective.

Using an ECU designed for a different engine is like speaking Chinese to a Russian guy, expecting him to understand you better than if you were speaking Russian. If you're asking if you can get a "better" ECU from another car, be it a newer Accord, a Prelude, etc... no. You will not gain anything. You may even do damage to your engine.
The ONE oddball exception is the P12 ECU from the 92-95 Prelude S, with the F22A1 engine. When used on an F22A1 or F22A4 engine, this ECU will give a modest gain of roughly 10hp. The reason why this works is that the ECU is tuned for an F22A1 engine that is identical in every way to the F22A1 found in the Accord. It's not really an "exception" since it is still an ECU that is tuned from the factory for that engine. However, Honda adjusted the tune to allow for more power (probably at the expense of a bit of fuel economy... maybe even engine longevity) in the sportier Prelude. That is the ONLY non-Accord ECU that will be any good... and ONLY if you have an F22A1 or F22A4 (which is the same as the F22A1, aside from the exhaust manifold.) If you have an F22A6, the P12 ECU will not help... the factory ECU remains the best you can get.


It's unlikely that any revisions in ECUs would ever be noticeable, if they even contain different programming or parts at all. Some differ due to year, paired transmission, origin of manufacture, or the country in which the car was sold. Any changes in minor things, such as idle speed, would be due more likely to age and corrosion than any actual factory-intended variation (in regards to idle speed, to my knowledge, every F22A shares the same factory-specified idle speed.)