Honda Prelude Forum - PreludeDriver.com

Alright, I am actually a little embaressed to have to post this but I don't want to pay a shop just yet. So on Saturday I power sprayed the engine compartment of my '92 SI. It wasn't the first time i've done it but this time I was a little more thorough ith the sprayer. So after I needed to move the car back into the garage, I started it up but I could feel, hear and see on the tachometer that the engine wasn't running right at all. Got it into the garage and could smell that it was running rich, so I pulled the spark plug coils and got all the water out of the holes. I also took out the plugs from the distributor cap and let that all air out. My battery light also can on while I had it running. I pulled my battery out and checked the cables and everything looked normal. The battery is less than 7 months old, so I know its not the problem. I got it all dried off, I took a look at the connections to the alternator and all looked secure. So I got it all hooked back up and then started it, and it fired up just fine, drove it around and it felt fine, except for the fact that it the battery light would come on when I got to around 1800 rpm and it would stay on until I dropped below that. That was yesterday, today she started up fine and the battery light didn't turn on until I had driven about 2 to 3 minutes, then it would come on at the higher RPMs, then turn off, but there didn't seem to be any pattern involved with the light coming on and turning off. I'm wondering if there is a loose connection somewhere.

I just went out and had her idle for about three minutes to see what she was going to do, and about 20 seconds after she ran the battery light turned on and then I turned on the blinker and it would turn off when the blinker would flash on. So I turned on the brights and the battery light turned off, then it would turn back on after turning the brights off. It seems like whenever there is a electrical load on the engine, the rpm's go up a little (just a little) and the battery light turns off, at least that is what it just did. Once again there doesn't seem to be a pattern to the light coming on and going off and I expect something different when I drive it later on tonight.

Also I got a little volt meter thing that plugs into my cig-lighter that displays the volts while the car is running. After letting her idle for about 3 minutes its showing 16.1 volts. I know that electrical stuff is hard to diagnose sometimes, but any help or suggestions would be nice.

Next Issue
I think that my AC pump (sorry haven't looked at the technical term yet) it starting to go out on me. Here are my reasons, today while driving around my AC would stop blowing cooled air, and it was just blowing hot. Sometimes it would return to blowing cold air but then it would die off and blow hot air. When I got home I listened to the engine and noticed a lot of noise coming from (what I believe to be the AC pump, its located just below the Alternator). Any suggestions?

Last Issue (for now)
When the AC was coming in and out, I noticed that the air seemed to blow in accordance to the engine speed. Harder when I was at a higher RPM and then when I dropped the RPM's it wouldn't blow as hard. It would do this no matter the setting I had it on, on the inside. I don't remember it ever doing this before. Whenever I would turn the AC on there would be an increase in vibration thought the car (another issue) but I never noticed any difference in how hard the air flowed.

More Issues to come!

Sounds like the water might have damaged your alternator.

It's never a good idea to spray down the engine without covering up the distributor, alternator, ignitor, etc. While the alt can withstand moisture in the under-hood environment, direct water sprayed into the unit can cause shorts and damage the electronic components. While pure water alone is not going to be the best conductor in there, mixed with the dirt and oil and solid contaminants, then you get a good conductor and damage results when energized. Chances are there might have been corrosion going on and this last episode just gave it a boot strap up to kill your alternator completely.

If you're going to hose it down, cover it up, or if you can't/don't do that, then absolutely do not run the engine until everything is completely dry.

16 is too high, but then I wouldn't trust a plug in cigarette lighter tool for accurate voltage detection.

Get a multimeter and hook it up to the battery. Set it to DC volts, hook red to pos and black to negative. Should read about 12.5 to 12.8 with the engine off. Start it up and the volts should then read between 13.8 to 14.8. Hit the lights and blower and it should drop down a bit and then recover back to the 13.8 to 14.8 range. Turn the engine off and it should drop back to the 12 range.

If you're not getting these readings then your alternator is probably fried.

That would explain the battery light, etc. I'm going with a bad alternator on this one. Helped to its death by getting it wet.
Could be wrong, but that's where I lean. Get the proper testing done to verify.

The AC compressor and/or clutch could be the culprit on the weird AC noise. If the clutch or compressor or both are going bad, then that is what you would get, hot and cold with extremes between and you would be hearing the bad noises coming from the unit, etc.

If the voltage is whacked due to the alternator, then you're going to see a decrease in the blower speeds when you let the engine idle or if you accelerate the engine. Tied in with this ... the AC unit in our cars puts a huge drain on engine power. If the AC unit is going bad, i.e. the compressor clutch is beginning to seize, then it will slow down the engine significantly when it engages because it's not able to do its job properly. The pull or draw on the engine from the clutch not letting the compressor spin freely will slow down the engine, lowering the rpms and causing the vibration.

Sometimes when I've got my AC running, wipers on, lights on and rear defroster on, the load of the electrical system pulls down my rpms and when the AC compressor kicks in or the engine cooling fan kicks on, the rpms drop significantly and I get a wicked low rpm vibration for a few seconds until the alternator adapts and output is increased.

That's just what I think based on what I know.

Get that alternator and voltage tested and let us know what happens. It might prove to solve your AC problems too. But until then, avoid using the AC so you don't damage it if it's not already.

I know it has been a while since I posted the original post but I wanted to follow up and let you know what happened. It was my alternator going bad and after a couple failed attemps of getting a used one I finally picked up a rebuilt one that has worked great ever since. Thanks for the help.

Thanks for letting us know!

Was that also the source of your AC problems?

I think the bad alternator wasn't sending a consistent proper amount of volts to the compressor and that was causing the AC problems. Because I can't even remember what the wierd AC noise was and ever since I got the new alternator the AC has worked great. Its starting to get consistently over 100 degrees here in the Phoenix Arizona area and still the AC runs like a champ.