I have a 1985 Honda prelude carberated an the battery light won't go out I bought a brand new altenator an battery but when I rev it past 3000rpm it goes out an it seems to be running off the battery I can only drive so far?like it fires right up on a full battery charge untill it dies

that meens your alternator is bad

change the battery cables terminals you can get them at walmart for under 5 bucks last time I checked

Your starter motor is either not getting power or in need of replacement. Otherwise, there is nothing wrong with your car.

Also check your battery connections for no corrosion there as well as by the starter motor. Low voltage circuits in a car are extremely vulnerable to poor contact issues.

Check the MAP Sensor... I had the same prob. My car would not rev past 2500RPM. I just ended up buying a new MAP sensor and fixed the problem.

From what you have described either the replacement alternator or regulator are faulty.all 1985 model here have the reg built into the alternator.Put a voltmeter across the battery terminals while running.volts should be 14 to 14.8 if it is being charged correctly,12.8-13.9 if it is poorly charging and less if it is only running on the battery.I assume that the fanbelt is tight and not slipping.There are several other reasons that can cause this fault but establish the basics first.Make sure that the main feed wire from the alternator to the battery is fitted onto clean terminal and isnt broken internally.To test this you can carefully check volts at the alternator terminal end,be careful not to arc out on anything metal while doing this.you may blow the charging fuse(check this anyway as part of test).the volts should be the same as reading from the battery.If it is lower,twist the wire about while reading and see if it changes.It will either need replacing if faulty or try new terminal ends first.Make sure that the replacement alt has the same plug configuration as the one you removed.Honda have a few different plugs that switch the trigger wire around(whether round or rectangular)Hope this helps you.if not get back with your test results and we can work together on this

I had an 84 Prelude with a similar problem. I will assume that the car runs just fine as though there is nothing wrong but has the light on. When this happened to me it was just a bad diode in the alternator. If the battery takes a load fine and shows good charge then take off the alternator, take it back to autozone or wherever you bought it and have them test it. I would bet there is a diode bad and they will give you a replacement. Good luck!

Even if you do it yourself you need to adjust it.I would get another mechanic to look at it also.Have you tried cleaners? 1 type you add to the gas the other you remove the air bonet and spray into the top of carb while running (have someone press on the gas lightly so you don't stall.Have you tried to increase the idle via the adjusting screw? has the auto choke been tested..adjusted? Good Luck.

if you can charge the battery and drive it for a while then sounds like the altenator has failed and is not re-charging the battery, good way to test is to charge the battery, start the car and turn the light on, if everything is dimm or the motor dies there is little to no charge voltage, and will require altenator work

sounds like you have a dead battery and possible a bad altenator have the battery checked out and replace if bad. If not recharge and if the car starts have the charging system checked out you may have a bad altenator or voltage regulator probably built in the altenator. Possibly the starter but not likely since it stalled while running.

check for electric short.
if you have factory or after market alarm, that may be the cause.