Alternator Output Drops Above 45 C After 75 km

Because he just may have that sort of mechanic. I had one tell me that all my spark plug wires must be bad since the plugs were badly carboned up. "You have to have FIRE to burn gas," was his summation.

Symptoms I brought it in with, were soot in the tail pipe, a different exhaust odor, and very bad gas mileage. Now, any bozo who's ever worked on engines would know to suspect the automatic choke from opening - but this being a fuel injected engine, it has no choke.

The real problem was the O2 sensor (part of the mixture feedback loop) If the O2 sensor fails, the computer modulates the injectors based on throttle opening and makes the engine run rich until it can be repaired. (the check engine light didn't come on, but the error codes, once I figured out how to access them, told me what was wrong) I took it to my regular garage and told them to just change the sensor, which fixed it.

You can stick the rotor shaft in a chuck and smooth down arc damage with a strip of fine abrasive paper - rebuilding a ripped up commutator is rather more expensive.

default wrote on 7/23/2017 5:01 AM:

You mean the brushes were actually "brushes"? Who would have suspected?

--

Rick C

If you bothered to read the thread you would have known the problem he has (unless he is totally misreporting the symptoms) is definitely *not* the alternator or any other part of the electrical system.

I think you jumped in over your head on this one.

--

Rick C

rickman wrote on 7/24/2017 2:01 AM:

I should have said "the charging system". It's late...

--

Rick C

What kind of vehicle is it, and what year?

On a '96 Toyota Camry I would stall when at a stop sign or red light, usually in 30+C weather. I finally figured out it was a bad coolant temperature sensor. I replaced that, and had no more stalls. The car had better fuel economy afterwards too.

Michael

That's how they got the name I suppose. Toy motors (when I was growing up) used a single piece of what looked like phosphor-bronze leaf springs resting on the commutators.

The East Orange Edison thingies where a jumbled mass of fine wires held in a clamp. I would have expected to see them all dressed in the same direction - but no, they went every which way. I don't know if that was how it operated or maybe the curators didn't have a clue as to how it was supposed to go.

The generator was just sitting on the floor, there was nothing like a steam engine to turn it nearby; it was just a display item.

Took a long hot ride w/ a good multimeter and the voltage of the lighter with lights, etc. off is 13.5 v and any misfiring was very hard to detect.

With everything on the engine is misfiring so bad it will hardly run but the voltage never drops below 12.5 v.

I'll try a new ignition control module because,

1. it's small and probably cools down faster than anything else that could be suspect.
2. it's cheap, and,
3. it takes 5 minutes to replace.

I'll report back in a few weeks.

Bret Cahill

Bret Cahill wrote on 8/9/2017 2:41 PM:

Ok, there are two questions answered after some weeks.

1) The voltage is not dropping (but then we knew that as the headlights never dimmed). 2) The engine doesn't have to quit, it first starts to misfire.

Still not enough info to really pinpoint a problem. Is this vehicle old enough to have points? I think you said it has a distributor. It could have points or a "reluctor" which is a hall effect switch and a pointed cam on the rotor. If points, did you check the dwell? If a reluctor, try checking whatever adustment that has.

--

Rick C

Any adjustment of the reluctor is not obvious. The coil in the distributor looks old but it looks old when it's cool out and working as well.

The problem is a 3 legged stool, heat + 75 km + 12.5 volt => bad ignition.

Remove any leg and there is no problem.

Bret Cahill

Bret Cahill wrote on 8/10/2017 12:45 AM:

I would stop focusing on the symptoms. You need more information. I'm not sure what the 12.5 volt thing is about. What does that mean, "12.5 volt"?

I guess you are saying you have a reluctor and no points. I don't really know anything about them except when they first came out I read there was still an adjustment of some sort, likely just timing which doesn't need to be checked more than once when it is installed. I'd say find a book that tells you if that needs an adjustment.

I'd say the misfiring rules out an open in the coil or resistor. That should either work or the engine will just quit, no misfiring.

Did you ever say what vehicle this is? That might help.

--

Rick C

Your troubleshooting approach is called "Easter Egging." It is not logical (or minimally logical) expensive, and time consuming.

Just think about the problem; there are always several things that can cause those symptoms. Find one possible cause that ties ALL the symptoms together.

What do the plugs look like - that will tell you if you have a problem with mixture. An engine needs air/fuel in the right proportions, compression, and a source of ignition at the right time. Any of those things being off will cause problems.

Sooty plugs = too rich, check the choke a stuck choke or partially stuck one will cause those exact symptoms...

Keep an open mind, you are "fixating," and that only hurts you.

Check the vacuum - burnt valve(s) will cause that problem and will cause the vacuum to jump around instead of hold steady.

What happened coincident with the problem? Get a tune-up and the problem started? (for instance) suspect something in the way the tune up was done. Did it gradually occur over time? Is it better or worse with humidity? etc., etc..

Learn to think analytically. It ain't rocket science, it is just auto mechanics and the guys that fix that stuff are called "grease monkeys."

For a long time I would not risk even one cent until I was 100% sure of the issue.

The problem seems to have disappeared with the new $7 ignition module. No problems in the heat, at least not on shorter trips. I might not know about longer trips until next June.

Bret Cahill

Bret Cahill wrote on 8/30/2017 1:18 PM:

I'm impressed that you could fix an alternator problem with an ignition module.

--

Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

Without taking it to Russia where they have an autoclave track there is no way to know for sure until next June.

Bret Cahill wrote on 8/31/2017 2:13 PM:

Maybe I should have included the smiley ;)

--

Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

Find out tomorrow.

Never got to drive in 45 C heat. Instead I cycled 60 km in 46 C heat today and nothing really went wrong except the water in the Camelbak tasted like dirty laundry water. Fortunately the water fountain was running at Sonny Bono.