Honda Prelude Forum - PreludeDriver.com

Howdy ya'll,

I own a '90 Prelude Si with 247,000 miles on it. Up until now I have only had minor issues with it; recently I started getting the check engine light either after accelerating from a dead stop (rather quickly) or after 20 or so mins of running at 65mph. Any reason as to why this may occur. Your help is greatly appreciated.

What code is the ECU throwing?

Here is a guide to find out the code:
viewtopic.php?f=4&t=706

Its weird, I get one long flash (-), 4 short flashes (-,-,-,-), and 3 fast flashes (--,--,--)

Is there a lengthy gap between any of these codes? I wonder if what you're getting is two separate codes.

Sounds like one of the codes is 14, which is the EACV valve. I had the same code on my Prelude two summers ago, and it also popped up after a long blast down the highway.

The behavior I got was that my car would bog if I didn't keep my foot in the accelerator at least a moderate amount. Do you get this behavior?

Yeah, The first one comes one (_), a second later I get the 10 code (_____), followed by the 3 code (__,__,__) followed by what seems to be another 3 quick burst (_,_,_)

That almost sounds like 3 separate codes. Code 1, Code 13 & Code 3. Which is Oxygen Content A, Atmospheric Pressure Sensor and Manifold Pressure Sensor respectively.

I'd love to see a video of this flashing. It's hard to make sense of the flashes. Is this the PK2 ECU? See the sticker on the side.

Thanks Spiffy, thats what I was afraid it would be. After reading up on it the AP Sensor is built into the ECU, which means get a new one. The other parts seem to be easy enough to find, where can I send the video once I get it?

Don't panic and go get an ECU just yet. Start with seeing if you can get the MAP sensor to stop throwing a code.

If the video is under 20 MB, send it to forumadmin@preludedriver.com. Better yet, upload it to youtube and post the link so others can see.

Thanks Spiffy, I will get the video tonight and upload it ASAP. A quick side note: I began having the "rough idle" issue this past week. Once the car warms up the idle bounces between 500-1k, not revving too high but will not stay stable.