Strange things after start up.

Alright. 1993 Daytona ES w/ V6 and auto transmission.

Recently, when I start the thing, the rpms jump up like they're supposed to, but then they drop down to around 500 rpm and the car starts shaking like it's going to die. While this is happening, I've noticed that the cabin lights and the dash lights start flickering. The rpms then jump back up, and the flickering stops. It does this for a few minutes and eventually stabilizes at 750.

Then when I shift it into drive, the rpms drop down to like 400 and the car shakes violently. Letting that subside, I put my foot on the gas, and it stutters a bit, then gets going. It does this stuttering thing for the first ten minutes or so of driving. After that, the car operates normally.

What the hell? I am completely stumped on this one.

It sounds almost like it's not charging or something. What does your ammeter read during the flickering?

I never noticed it before, but the ammeter goes down as well. When it's not shaking/flickering, it reads right in the middle. When it starts acting up, the ammeter drops down a bit. What would that mean?

It means it's not charging. How old is that battery?

My 2.2 would do that when the belt got old enough to be smoked and it would charge only at certain rpms. Sometimes depending on the temperature outside and how wet it was, it might squeal.

Alternator might be going too.

Well, it's definitely not the belt, because I replaced it a month ago.

The battery's been in the car since I've had it, which is about a year and a half. Hell, it could be the same battery from '93.

While I don't want to think about that, the alternator could very well be crapping out.

Alright. 1993 Daytona ES w/ V6 and auto transmission.

Recently, when I start the thing, the rpms jump up like they're supposed to, but then they drop down to around 500 rpm and the car starts shaking like it's going to die. While this is happening, I've noticed that the cabin lights and the dash lights start flickering. The rpms then jump back up, and the flickering stops. It does this for a few minutes and eventually stabilizes at 750.

Then when I shift it into drive, the rpms drop down to like 400 and the car shakes violently. Letting that subside, I put my foot on the gas, and it stutters a bit, then gets going. It does this stuttering thing for the first ten minutes or so of driving. After that, the car operates normally.

What the hell? I am completely stumped on this one.

Same thing happened to me, and I have the same exact car. I ended up fixing it. Before you spend any money on an alternator or battery do the following, you may be surprised.

Right behind the battery there is a large black ground wire. All power for your car goes through this wire, and the voltage regulator uses this wire to determine how much power to generate.

Pull the link apart and clean it off and put it back together again.

If your voltmeter is reading low when idling it is a possible sign that it just doesn't have the ability to read correctly so the alternator is not asked to generate the extra current.

Let me know how it goes. The connected is right near your auto/shutdown relay and coolant fan relay just in front of the driver side strut when you open the hood and behind the battery. It looks like a fuse holder but it isn't.

Good luck

Are you talking about the big ol' black plug looking thing that has like 8+ wires going into it? I took that apart and cleaned it, but it didn't seem to have any effect. Of course, I probably misunderstood what you meant. I see the two black things (not sure if they're wires or hoses, they're pretty big) coming out from the box on the left of the battery, a bunch of those plug things (are those relays?) and some black hoses. Would this be under the air intake hose coming from the ECU? That's where the thing I was messing with was.

Are you talking about the big ol' black plug looking thing that has like 8+ wires going into it? I took that apart and cleaned it, but it didn't seem to have any effect. Of course, I probably misunderstood what you meant. I see the two black things (not sure if they're wires or hoses, they're pretty big) coming out from the box on the left of the battery, a bunch of those plug things (are those relays?) and some black hoses. Would this be under the air intake hose coming from the ECU? That's where the thing I was messing with was.

Ok, I will check under my hood when I have a chance to and tell you how better to located it. But it does sound like what you are talking about.

here is what happened to me and why you must check this wire first.

My car seemed to run fine, but when the AC and the cooling fan was on I would watch my volt meter drop to 10 volts when the engine was idling. While driving down the road the car was ok. After some time it got worse and worse until finally just turning on the lights at night would make the car hickup and stall. I also noticed at Idle the car didn't have a lot of power according to the volt meter, just under 12 volts. When I press the gas though, it would go up to 13 volts. I kept thinking it was the voltage regulator, which is in the computer, so I replaced it the computer ($200)

No change, then i replaced the alternator still no change. Finally, when it got so bad that sometimes I couldn't start the car I read in my shop manual about checking for a good ground if the alternator doesn't seem to charge. It uses this good ground to determine what the current voltage is and thus determines the amount of current that needs to go through the field coil so the alternator can generate more current when necessary. Basically, without a good ground no charge.

That ended up being this black wire that I spoke of. Once I cleaned it off, had to take some plyers and pinch it a bit because it had a male and female connector. The female part was spread too far open so I pinched it with some pliers for better contact. Now when my AC turns on the Voltage stays at at least 12, instead of going to 10 as before. Also, at idle I see 13 volts, not the old 11.9 I did before.

So after changing all those components it was just a faulty connecter, therefore, before you spend any money, make sure your alternator has a good ground because this could be causing the fault.

If this doesn't fix it then I would figure test your battery and alternator at a shop. They should be able to hook up a restistor to the battery and see if they get the current off of it that it specifies.

Also, the alternator is easy to remove and test as well. Takes about 5 minutes to remove.. I can help you with this if you have questions. Just remember to use a 1/2" breaker bar to remove the serpintine belt and disconnect the battery before you attempt to remove it, then take it in and have them test it. If those components are working then it is probably the SBEC, which is the voltage regulator. If you want one, I have an extra one left over from my swap that didn't originally change anything.

The black wire I am talking about is a large, looks like 7 gauge wire, and runs into a triangular wire connector with about 8 other wires coming off of it.. That is what I remember from memory. Tomorrow before I drive the car to work I will look at it and give you a better description.

Good luck.

Are you talking about the big ol' black plug looking thing that has like 8+ wires going into it? I took that apart and cleaned it, but it didn't seem to have any effect. Of course, I probably misunderstood what you meant. I see the two black things (not sure if they're wires or hoses, they're pretty big) coming out from the box on the left of the battery, a bunch of those plug things (are those relays?) and some black hoses. Would this be under the air intake hose coming from the ECU? That's where the thing I was messing with was.

The three black things that I think you are talking about are relays. They are held in place by the side of the engine compartment.

starting from the front, the first relay is your Auto/shutdown Relay. this Relay shuts down the fuel pump, power to the alternator field coils, etc and ignition coil when it determines that the engine is not running.

next to it, as we move towards the back of the car, is the AC/clutch relay and then finally the third one, firthest back is the cooling fan relay.

The metal box, shiny metal that is on the strut tower is your starter relay. Hope that helps describe some of the stuff you are looking at. All these things will not affect your charging, but you asked about them so I responded.

The box that you are talking about is the criuse control module. It connects. I would have to look at in the daytime, but it may have a vacuum hose hooked to it. Underneath you will see a black vacuum hose that goes straight down to a vacuum accuater for the throttle cable, I believe, like I said, all from memory right now.

None of these things have anything to do with your charging system though. Look for a large wire, I think you found it, It looks like a fuse connector but has no fuse in it.

Thanks for the help, Tamerlane. I found the connection you were talking about. (Black, take it apart and there's a plug side and a socket side.) However, when I took it apart, there didn't appear to be anything wrong with it. No corrosion, dirt, grease, nothing. I tried using needle nose pliers to close up the socket side a bit, but that wasn't very effective, and I'm not even sure that was necessary, seeing as it wasn't spread out very wide. In my experience, sometimes just taking something apart and putting it back together will fix an electrical problem. The real test will be tomorrow morning when I start it completely cold, and see if this did anything.

I read in another post about how your Daytona runs rough when cold. I too changed my throttle body to a bigger one. (52 mm, I think, has vacuum connections on the top.) Weird thing is, it ran fine cold with the new TB for a long while (I plugged those vacuum points with two rubber things that my dad got from work. They seem almost made for the purpose.) This rough idling problem I've been having just kind of came by on its own.

So uh, any other ideas? :biggrin:

Thanks for the help, Tamerlane. I found the connection you were talking about. (Black, take it apart and there's a plug side and a socket side.) However, when I took it apart, there didn't appear to be anything wrong with it. No corrosion, dirt, grease, nothing. I tried using needle nose pliers to close up the socket side a bit, but that wasn't very effective, and I'm not even sure that was necessary, seeing as it wasn't spread out very wide. In my experience, sometimes just taking something apart and putting it back together will fix an electrical problem. The real test will be tomorrow morning when I start it completely cold, and see if this did anything.

I read in another post about how your Daytona runs rough when cold. I too changed my throttle body to a bigger one. (52 mm, I think, has vacuum connections on the top.) Weird thing is, it ran fine cold with the new TB for a long while (I plugged those vacuum points with two rubber things that my dad got from work. They seem almost made for the purpose.) This rough idling problem I've been having just kind of came by on its own.

So uh, any other ideas? :biggrin:

I would start with the easy things first. If you know for a fact that the voltmeter is dropping to low voltage during idle you might want to have your battery and/or alternator checked.

But before you remove the alternator take the battery out first and check the SBEC. It is the black box that is on the driver's side fender, it has the air intake connected to it to keep the computer cool. Since the SBEC is the voltage regulator you might try and remove the 60 pin connector and clean it off and put it back on, perhaps there is a short here. That would cause your charging system to not work.

There is one bolt screw in the center of the connector. If you losen it it will automatically separate from the computer.

After you have hooked up the SBEC again, hook up your tested battery and see if it works. If not, move on to the alternator.

You should be able to take them into auto parts store and have them checked for no charge.

I won't bore you with how to remove the battery because I am sure you have done that.

Here is how you remove the alternator.

1. Disconnect the positive battery lead.
2. Use a 1/2" breaker bar to fit into the square hole in the ilder that holds the serpentine belt on. The idler pulley is just above the power steering pully and below the alternator. You can't really see it from the top, but you will find it right in the middle of the idler arm towards the pulley. You don't have to take anything apart to get to it with a half inch breaker bar.

Once you have inserted a half inch breaker bar in the square hole you can lift up on it and the belt can be removed.

3. Use a 15mm socket wrench along with a 15mm box wrench to remove the nut and bolt that hold the upper part of the alternator.

4. Use the 15mm socket to remove the bottom bolt.

5. Now remove the alternator and then you can gain access to the wires on the back for removal. have it tested at the shop.

After this is done then you know you will have a good alternator and battery. From what it sounds like, I am going to bet that the alternator might be bad, that is, if it is not the SBEC.

Let me know how it goes.

All,
Someone has missed the boat!
The reason the volts are dropping and the lights are flashing is because the motor is idling to low and the alternator cannot work below 750 RPMs and the oil pump cannot maintain pressure at those low RPMs.
The description is typical of a vacuum leak. The choke is coming on for cold start which enriches fuel mixture. Once the choke adjust, the idle drops. Once the vehicle is warmed up it can run on a leaner mixture. Find your vacuum leak.
Dave
My Way is the Highway

All,
Someone has missed the boat!
The reason the volts are dropping and the lights are flashing is because the motor is idling to low and the alternator cannot work below 750 RPMs and the oil pump cannot maintain pressure at those low RPMs.
The description is typical of a vacuum leak. The choke is coming on for cold start which enriches fuel mixture. Once the choke adjust, the idle drops. Once the vehicle is warmed up it can run on a leaner mixture. Find your vacuum leak.
Dave
My Way is the Highway

Dave,

I would agree with you except for the fact that the car is supposed to idle at 700rpm. This is the idle for the 3.0 litre v6 , which is lower then the 2.2 liter motors. Mine will generate 13.9 volts at 700rpm

Hence, it is a problem with the voltage regulation and/or alternator it you do not see it charging at 700 rpm. Now, if it goes lower then that, then a vacuum leak could be the cause.

Ok,
Here is the easiest trial to prove your point.
If the charging system is the culprit, then hook up a battery charger to the car and start it. The charger should stabilize the electrical system and, if your right, the car should run normally.
What do you think?
Dave

Ok,
Here is the easiest trial to prove your point.
If the charging system is the culprit, then hook up a battery charger to the car and start it. The charger should stabilize the electrical system and, if your right, the car should run normally.
What do you think?
Dave

Yes, assuming that the alternator has a good ground and the connections are good to the SBEC. In my 3.0 Liter the SBEC controls the amount of voltage going to the field coil. This is what ultimately sets the current that is generated by the alternator. If there is a bad ground then this system will not work properly even with a good alternator and battery.

I had recently discovered on my car, after changing the alternator, which had no effect, that there was a short in my ground wiring. Once I repaired the short my system charged fine.