Honda Prelude Forum - PreludeDriver.com

Ill start off with..I put 87 unleaded gas in my car for the first time since the engine swap. For the past year i have been running 89 unleaded. Since the cold snap has happened down here in the south I threw a code 9. I thought it was funny that the the code literally says has trouble starting in the cold, and thats exactly what has been happening. The car hesitates just enough to feel rough, but only when i start it up(in the cold).
My question is How long does the CYL sensor usually last? I am definitely going back to a higher octane gas and i think that should help, i just happen to fill it up with 87 this one time.

Not sure on how long the CYL sensor usually lasts. Never had one go out. I believe that there is a separate ECU code that is thrown if the CYL sensor fails though.

This Code is affecting the acceleration now. I first thought it threw a different code, but i checked it yesterday and its the same. When i start up the car the check engine light comes on. Upon accelerating the car hesitates intermittently. I have figured out that if i drive for around 10 min and the car is fully warmed up i can turn it off and on and it works like nothing ever happened.

Any plans to replace the CYL sensor?

Your problems remind me slightly of trouble I had once with my EACV valve. In my case though, warming the engine would make things worse, not better. The engine would bumble and bog until I really put my foot in the pedal, then all was fine.

On a related note, I've also seen Preludes have acceleration problems caused by bad TPS sensor. These haven't been temperature dependent though.

I dont know if ill replace the cyl sensor yet. This morning i gave it a little gas as soon as i started it up and no check engine light. The car ran fine all day. I think ill test this method. I do have a spare tps sensor from and extra throttle body, it may come in handy later. I did adjust the EACV valve last winter when my b21 was having trouble. I may have to tune it again for this engine.

i have been giving it a little gas is the morning on start up and this method is working every time. No check engine light so far.

Great to hear.

Well, now it seems like i cant get rid of code 9. My check engine light comes on about everyday day now, not just when its cold. Looks like ill be shopping for a camshaft position sensor and see if that solves it.

The CYL sensor is integrated into the distributor, is it not? You might be able to just source a different one from a wrecker and see if it helps. Would cost far less.

the cyl sensore is stand alone. Ive seen them from $44-$100+. I ran into a mechanic restoring a prelude and he told me it could be the timing is just a hair off, enough to throw the sensor off. I dont know if that could be true. Once the timing belt was changed the code didnt trip till i put a few thousand miles on/winter started. I emailed a wrecker i know to have preludes to see if he has one. Here is some pics of the car he was restoring w/custom paint job. He said he will probably sell it once he finishes. He got it for $300 and it was rusting away.

Great pics. Thanks for sharing those.

Interesting idea about the timing. Have you checked your timing recently?

I have not checked it recently. I have to give the guy who worked on my car a call and see what he says.

hey guys,
I"m new to this site. I recently purchased my second 90 lude. About half the engine sensors weren't wired. I preceded to replace the missing part of the harness
and discovered that my ecu was for a 2.1 and not for the 2.ol that was in the car. i made the necessary changes and elleviated all the trouble codes with the exception of 9. I redid the harness thinking that the 2 ohm in the circuit was enough to cause a bad reading. i then replaced the sensor and the code went away for one day. Now i've been driving the car and im getting a 1 that i'm wondering is being caused by the 9 and the way it runs rough at low rpm.
i tried to time the car when i first got it but was confused about markings when i set my advance and when i didn't . So i gave it to a friend and he said it was perfect. what does this sensor control?
I'm definately interested in hearing more on this 9 thread.

kmeredith95 wrote:hey guys,
I"m new to this site. I recently purchased my second 90 lude. About half the engine sensors weren't wired. I preceded to replace the missing part of the harness
and discovered that my ecu was for a 2.1 and not for the 2.ol that was in the car. i made the necessary changes and elleviated all the trouble codes with the exception of 9. I redid the harness thinking that the 2 ohm in the circuit was enough to cause a bad reading. i then replaced the sensor and the code went away for one day. Now i've been driving the car and im getting a 1 that i'm wondering is being caused by the 9 and the way it runs rough at low rpm.
i tried to time the car when i first got it but was confused about markings when i set my advance and when i didn't . So i gave it to a friend and he said it was perfect. what does this sensor control?
I'm definately interested in hearing more on this 9 thread.

To clarify: when you say "what does this sensor control?" you're referring to the CYL sensor?

Also, feel free to create a new thread for your issue so we don't drive this one off the OP's topic. I'm sure 91darkness will offer his experience and give you a hand in a new thread.

anyone reading this check out the the post on the ''cyl sensor'',i recenly started.