Skip to main content

I've had an intermittent starting problem for a couple of months. You'd turn the key and it behaved like a flat battery. It only happened every 2-3 weeks and had me flummoxed. Later on it starts just fine.

I began data logging every time I drove until I finally caught it happening. The battery voltage had dropped to 8 volts while cranking despite being well over 12 before I hit the starter. I truly doubted that it was the battery and knew the alternator was charging.

I checked the tightness of all the connections and bought a spare starter switch to carry. It happened again on Friday after a 20 mile drive and I had a brainstorm. The previous failure had happened after a 45 minute drive.

It might be a failing connection that heated up while driving. The only other thing I had inline with the battery was a cutoff switch. Before we headed out yesterday for a staycation on the other side of the island, I bypassed the switch. No problems so far. I might have found the culprit!

IMG_20190903_191805

Attachments

Images (1)
  • IMG_20190903_191805
Original Post

Replies sorted oldest to newest

.

Probably not related, but this sticks in my head.

Many, many years ago, vacationing on your island, we had to call the rental car company the second morning there to come start our almost new Nissan Sentra.

They knew what it was as soon as we called and said it happens there 'all the time'.

Turned out to be condensation inside the distributor cap (I told you it was many, many years ago).

I'd grown up in east coast winters and in humid summers, but something about the combination of climate factors there seems to somehow make condensation in auto electrics more an issue than in most places.

I just chalked it up to part of the daily hell of living on Maui.

.

.

.

...We've got 3 huge green sea turtles working the reef in front of the condo...

Dammit, Michael, now that's what I'm talkin' about.

Who cares if the car breaks down someplace, anyway?

Wherever it happens - at the hardware store, laundromat, or gas station - just leave it for a few hours, put on some flip-flops (okay, okay - slippers, then) and it's 50 yards to the nearest beach.

.

Solution found on the starting problem. I've got a 90 amp alternator because of the external oil cooler fan and the fans on the air conditioning condenser and evaporator. I logged voltages on my trips around the island and found that when the engine was hot and I had the AC on, the battery voltage dropped well under 12 volts at 2200 RPM. So, long trips and the car wouldn't start the next time. 

I measured the DC amps on the alternator at full draw and it only hit 52 amps output. Checking the output for alternating current showed over 8 VAC. My thoughts were that a diode or two had failed.

I ordered a 90 amp Compufire alternator as a replacement. It was heavier and had extra vent fans compared to the EMPI one I bought a couple of years ago. They claim to use USA parts for the Compufires. Stuck it in and instantly charged over 13V at idle.

I'll take apart the EMPI and rebuild the diode pack and call it a spare. It was clearly 2nd class quality.

So, I'll reconnect the battery cutoff switch and see if it introduces any problems, but otherwise, I think the partial failure of the alternator was the culprit.

Add Reply

Post Content
×
×
×
×
Link copied to your clipboard.
×
×