Engine cuts out randomly at speed

[jamancol]

Hey guys,
Got a problem maybe you could help out with. Lately I've been having issues with my stock '95 SI AT prelude cutting out. The problem started off initially several months ago with an occasional random flutter while driving or accelerating at speed (3rd or 4th gear cruising down the street/highway). Some days the problem would not happen at all, others it would happen repeatedly in a row. At the time I would just rev the engine and it would go away. Lately though (last two weeks) instead of fluttering, it just cuts out. I'll be driving down the highway and the car will just shut off (no dash lights, no ignition, wipers stop if their on, radio stays on). I coast it over to the side of the road, put it in park, crank it over, rev it a couple times, and it runs like nothing happened.
The problem has also occurred at start up. Sometimes after turning it over, if I don't rev it a few times first, it will just cut out when placed in gear or within a few seconds of pulling out. This doesn't always happen, but it does happen often enough to be worrisome.
Engine temp has been both cold, and normal when the problem has occurred. When highway/steet driving, its usually in the 2500-3500 rpm range, and in 3rd or 4th gear. Replacing the plugs and fuel filter did nothing to fix the problem. Alternator & battery both seem to be good. Any ideas?

[spiffyguido]

This definitely bears the marks of an electrical problem.

It's possible that there is a fault in your ignition switch. I had a Prelude once that had the ignition switch go bad and it would cut out like that at the weirdest times. However, I also had real problems starting the car sometimes, and my radio didn't stay on because the whole car was effectively shut off as if the key had been turned to the off position. Still, something to think about.

You can rule out fuses, because they only fail once, not multiple times, so you problem is either a short, or relay related.

I've heard of a lot of people having trouble with their main relay, and this may be the case for you. They've noted that this is often affected by temperature.

One potential way to test the ignition switch is to start the car, and then wiggle the key a bit. If the contacts are bad, the car may shut off if connectivity is lost.

[jamancol]

I'll give the key wiggle test a try when I get off of work. Any chance it could be a fuel pump or Ignition coil problem?

[spiffyguido]

If it was, you'd likely get sputtering, not just a complete shut down. Your dash lights are going out and everything, no?

[jamancol]

When the car dies, there are no dash lights lit... Before though, back when it was just doing the fluttering at speed, the check engine light would occasionally come on after it fluttered and I revved out of it. (sorry forgot that detail in the post)

[spiffyguido]

Do you know if the ECU is throwing a code? That could provide clues.

[jamancol]

I just saw a post on how to check the codes today, I will have to try that this weekend, and see what it comes up with.

[spiffyguido]

Great. Posts like this should help you out:

viewtopic.php?f=3&t=14

[jamancol]

Ok, so I accidently left my headlights on after driving in the rain, and killed my battery yesterday. I think it may have cleared the ECU...Doh. Guess I have to drive it till it happens again before I can give you more info. I did try to read the codes though. When I shorted the connection on the diagnostic connector I noticed the CEL did not flash, but the SRS light was flashing constantly. Is this supposed to happen, if there are no codes to read?

[spiffyguido]

I'm not sure about the SRS light. This may be what is supposed to happen. You SRS system is completely separate from the rest of you car, so I would just focus on the CEL codes. The next time your engine cuts out, be sure to check the code. Your battery dying may have cleared the stored code, so you may need to have your problem happen again before you can get the code out of your ECU.

[jamancol]

Ok, so just a quick update, so you dont think I forgot. It looks like clearing the ECU may have done something more than just clearing the codes. The car has not had the problem since that day. Don't exactly know what that means, but I also have not had a chance to drive it on any multi hour trips either.

[spiffyguido]

Honda ECUs do "learn" a certain amount after they are reset. I'm not sure what they store, but I believe it's something related to environmental conditions and past codes. Clearing it may have allowed the ECU to relearn a few things and now your fine.

To be sure though, go on a long blast down the highway. You don't need to run the engine hard, but a good run at consistent engine rpm (highway cruising speed, for instance) is a good way to raise any problems that might be there. When you're out on the highway, your engine isn't having to cope with the TPS system bouncing all over the place and engine loads changing all the time. Cruising speed lets the engine find its happy place.

[jamancol]

Well, no more cut outs, even after taking a 3 hr round trip the other day at highway speeds. A whole new symptom popped up this morning though on the way to work. Don't know if its related, but I kinda think it might be. I clicked on my turn signal and when I clicked it off the signals turned off, but it kept making the clicking noise. It wasn't just that though... in tune to the clicking, every light and gauge on the dash, plus the radio kept blinking on and off as long as I was driving. When I would come to a stop and idle (at a light) everything would come back on like nothing was wrong. Then it would start back up as soon as I started moving again. The engine never choked, sputtered, or did anything out of the norm... but it was like my entire electrical system went wack on me. I used my little wire Ive been keeping in the car to short the diagnostic connector when I got to work, and nada... no error codes. Any ideas?

[spiffyguido]

This is quite possibly the strangest problem I've ever heard of on a Prelude. We'll get it fixed though.

We can assume that your problem is electrical, and it almost sounds as though your dash lighting is somehow shorting out on your blinker relay. Does it only happen when you signal one direction, or both? You must have a short somewhere, anywhere from the steering console to in behind the dash. The clicking is from a relay, so you need to locate that relay and see if the problem is there. Can you try to locate the relay that is making the clicking sound?

[jamancol]

Its up to old tricks again. When I left work, it did it for about 2 seconds, and then stopped. It has not done anything out of the norm since. It is being very sporadic with these symptoms, and its always different when it comes back. Is it possible, a car can have a poltergeist? lol Seriously though... I have not had time to dig around with the electrical system yet. I'll let you know any new info as it comes. Oct is a crazy month for me, so I'm not sure if I will be able to get to it, unless it decides to die completely on me.