Sorry this is long, I really appreciate any help I can get, thanks in advance.

Background...My car(94 Si) was recently in the shop. It had the oil cooler o-ring, the lower intake gasket, upper plenum gasket, intake gasket to head, 3 different injector seals(12 total, 3 per injector), and injector seal o-rings replaced. Everything seemed fine driving away, until about three miles down the road, the CEL comes on, and the car has the problem described below. Went right back to the shop and had them look at it again. They said it was probably my spark plugs(they were Autolites), and that Autolites don't run very well in Hondas. So I got some Densos, put them in, all is fine...for a day. I really don't want to take it back to the shop, as I don't have much money left, nor the desire to pay more money...I've spent almost $4000 on problems in the past 4 months.

Now, after replacing the spark plugs, the problem seemed to go away, about a day later, it's back. Everything is completely fine until the CEL comes on(completely random, could be after 1 mile, or after 50, no set time that it happens). When the CEL comes on, shifting into neutral, the engine drops to about 400 rpms, almost stalls, and then pops back up to 700-800, and fluctuates ever so slightly, just enough to feel it. There is also some hesitation at higher rpms, and I was told by the shop that it's a misfire. My friend said to reset the ECU, and I did, so we'll see if that helps anything. Any suggestions, things I could check? Thanks again.

-Sam


[Modified by Amnesia, 8:25 PM 1/6/2003]

 

a misfire would make an obvious sound.... your Prelude wouls sound like a Briggs & Straton powered go-kart if you had a misfire. most likely the proplem is something in the TPS or MAP sensors, or it IACV, since you have a fluctuating idle. check the code yourself, b/c the shop is most likely just trying to screw you

 

Ok. Can you tell me how to check the code? I've read how to do it, and the way I do it, it doesn't work. I thought the problem was the fact that when the CEL is on, the car is on, and when I turn the car off, I have to turn it on and drive it a random amount of time before it comes back, so that doesn't allow me to check it. You're supposed to connect a paperclip or something similar to both sides of the yellow service connector, then turn the key to the second position and count the fast and slow times the CEL blinks, right? If so, it doesn't work for me. Thanks.

 

Damn $4000 and you still have the H23? BTW, how much did they sell you the Densos for?

Check the code and let us know. It's easy. Look behind your radio, there should be a blue connector. Pull it out and jump it (run a wire from one opening to the other). Then turn your key to Acc...and count the amount of time the CEL blinks. Long blink = 10. Short blink = 1.

Good luck!

 

Yes, I still have the H23 ...parents make my life so dull. Pretty much a new engine though, just not the crap attached to it, hehe. The Densos were about 14 bucks. Blue connector? The guy at the shop connected the the yellow one, and I read yellow on a different prelude website. Hmm...Now I'm confused, I'll go out now and look for a blue one. Thanks again.

 

Sorry, I don't have my manual here with me...but I'm pretty certain it was a BLUE connector?

*edit* Here, found a picture in a hurry. Although it says RHD Prelude, it's still the same connector.



It's the TWO pin connector. And I believe the YELLOW connector back there is for the SRS?


[Modified by 98CTRCoupe, 1:11 PM 1/6/2003]

 

Ok, I just looked and I see a yellow two pin connector, not connected to anything and somewhat behind the radio are a two pin, and a three pin blue connector, both connected. I tried checking it with the yellow one, nothing, and I pulled out the two pin blue one and tried also. With the yellow the car was normal, but with the blue, the CEL stayed on. It didn't blink, it just stayed on. I have no clue what that means. I can take pictures of the connectors if need be. Thanks.

 

Make sure you're making good contact with the connector.

And I hope you didn't turn the car on...just leave it in ACC (2nd click).

 

No, I'm definitely not turning the car on, and I'm sure I'm making good contact as well. Could it be possible that since the CEL disappears until I've been driving for a random amount of time, the problem can't be diagnosed using this method? This is so frustrating...

 

if the CEL disappears, then drive around, wait for it to come on, then pull over, leave the car on, then diagnose the problem. i take back wahat i said earlier, if it is a random CEL that only comes on after driving, then it is possible that the problem is with the knock sensor, or another sensor that doesn't get a signal until after the car reaches operating temp

 

From what I understand, ANY code that is tripped during a drive will be STORED in the ECU. Even if it doesn't stay on, it's still stored...so when you jump the connector, that code will pop up. Trust me, I've been through it all. Only recently have I diagnosed all the CEL's that popped up. And I finished my swap like 8 months ago!

It's wierd how it doesn't blink when you jumped the connector. Hmmm...

 

sometimes they don't stay stored, it depends on which code it is..... my teg does that **** all the time

 

Yeah, the guy at the shop said that my car doesn't store the codes(don't know if this is right, but the way my car is acting seems like it is), so I have no clue. After I reset the ECU, I drove around probably about 20 miles tonight, and nothing popped up and everything was normal. I hope it stays this way(knock on wood). If it does pop up again, what can I check for myself, and what would be the best things to check? Thanks again guys.