plat

The old condenser tested good, 0.46 micro farads and the new one is 0.47, so I guess that couldn't have been it.

I do know there is on open diode in the alternator but it has never caused any problems. Could that electrically damage anything or the coils?

JvG

Hmm..... don't know about that diode, but I'm curious about the regulator. Have you taken voltage readings between the battery posts? Is the voltage higher than 14 volts?

Are you headlights brighter than normal?

plat

At idle I get 13.2 volts at the battery, and this rises towards 14 when I rev the engine. I will check for sure where it tops out at. Haven't noticed any light brightness changes or other electrical effects. My understanding of it is that an open diode will cause part of the alternating voltage from the alternating to be lost on each cycle and so less power will be produced and it may be very 'noisy' electrically, like produces pulsing dc instead of steady dc.

Yesterday the last original coil failed so I got another autozone one, which melted down in 3 miles and caused greater damage.

So now there are no brands with a clean track record. Maybe this autozone was just a fluke, all I can do is swap it under warranty and try another.

Has anyone ever seen something like this happen before?






Do you guys think a shop would have any chance of solving this? Would it be worth the diagnostic fee to have someone look at it?

JvG

You already know that you need to replace the alternator.

We also know that your coils are not happy about the amount , quality, or voltage of the current they get. This is quite likely due to the alternator. They probably can't cope with irregular DC current.

The shop fee would probably disclose what we already know. Bad alt.

So why not spend the money on something useful.
Such as an alt it needs anyway. It just might fix your coils issue a's a result.

plat

Honestly I don't think I would spend that much without being sure that it would fix it. Because if it didn't, then it must be the ECU and that would be a bunch more.


And there is some bearing noise in the transmission, so that will have to be rebuilt at some point as well.

I have over $5000 in the car now and it will be thousands more to get it right so I have a tough decision to make.

sb001

I have no idea how you figured out you have a bad diode in your alternator- but if you're sure about that, then IMO it's worth grabbing a good OEM (O E M!!!!!!!!) alternator from the salvage yard, Shouldn't be more than $30-$40 and would tell you whether that's the issue.
You're sure that bearing noise is coming from the transmission?

JvG

You havever an alternator which is producing dirty power. Dirty power can blow out electrical devices. You coils blow constantly.
See a cause and effect yet?
​​​

JvG

Please look at today's repost about a 7.5 amp alternator fuse.

Supposedlya blown on leads to 15 volts from the alt.

That in turn could cause coil issues.

plat

I had no idea about that fuse, I will check that and the voltage again.

AAA tested my alternator when they jumped me after I left my lights on. His machine showed an open diode and he said the alternator would fail shortly, but that was months ago.

I'm all for putting in a used alternator if I can do it myself. It looks feasible.


I'm pretty sure about the bearing noise. The input shaft bearing I think it would be. It's a rattly, gravely noise with a little whine as well, heard at lower revs in 1st, 2nd, and some in 3rd when accelerating. I have changed the gear lube out for MT90 and it has turned grey, I assume because of holding tiny metal debris.

The transmission doesn't leak or have any shifting problems however. It probably had this noise when I bought the car over 20k miles ago but its has slowly gotten worse to where I'm aware of it more.


If just those bad bearing(s) could be replaced for much less than a full rebuild, I would go for that.

plat

I just checked everything out.

After cold start, I have high 13s volts at battery, which shoots well over 14 with a little rev. Once warm, there is 13.2 volts at idle and this never rises over 13.5 no matter how high you rev. Seems strange?

When warm, there is just over 13 volts feeding the coils.

No fuses blown under the hood.


I scoped the coils and battery voltage.

Coil trigger signals all looked like this. 0 on the scale is the first line up from the bottom, and scale is 0.2 volts. Peak voltage is 1.2 v and minimum is 0.6 v. So, the trigger signal NEVER turns off completely. Is this normal?






The battery voltage looks like this. Now the scale is 5 volts and 0 is the middle line up. So this is read around 13 volts as expected, and with just the slightest hint of a ripple, which is barely visible.. Is this fluctuation enough to cause problems?

sb001

Trust me, if I and my buddy can install one (which is what I did on my 99) you can do it. There are YouTube videos to guide you as well.

The reason I asked about the bearing noise is because... you're sure that's not coming from your alternator pulley? Check the belt while you're down there-- you could potentially solve two problems at once.

sb001

JVG I just read that thread--

Plat, here is the relevant post from that thread:

So be sure to get under the hood and check that 7.5 amp fuse!!! This could also explain bad bearings in the alternator/ pulley if that indeed is where the noise is coming from! Good luck

EDIT: Just saw your post saying you checked the fuse. Never mind...