Strange alternator/charging problem, help needed!

[Swampy442]

Car is a Toyota Crown 1JZ GTE VVTI. And please excuse the long post! I need answers sharpish because if it is the alternator Ive got to sort another car ready for monday :/

 

Driving home tonight from Surrey to Lincoln (about 160 miles) when short distance into the journey the ABS VSC etc lights came on. No big deal I thought, they come on for pretty much any minor fault, so carried on. A while into the journey I noticed the radio kept cutting out, assumed it was the DAB unit I had, carried on.

Got to around Oxford and the radio dies, the clock was looking a bit dim, put 2 and 2 together, alternator failure, shit. Parked up, checked the aux belt, battery connections etc. all normal so assumed it was the alternator. Got back in the car et viola, all was back to normal!

Carried on, bit later the ABS lights etc came on again briefly, then went off. Turned off the stereo and climate/fan for good measure.

Then finally, by Leicester, wipers started to slow, I was out of volts. Parked up and waited for AA. By this time Id covered over 100 miles.

 

AA man puts a new battery in, car fires up, checks the alternator output, 14.7v, all good. Drove the remaining 40 miles without issue, got home, checked the charge rate again, 14.7v, cracking! Put the old battery back on the car (after being on charge in the back of the AA van) attempted to get some food but had to turn back, same issues.

Came home, put a known good battery from my brother's car in, all was good, I assumed the battery, sorted.

 

Now heres the killer, trip to McDonalds is about 2 miles maybe? It killed that second battery in that journey but, just when everything was about to die, suddenly *click* alternator kicked in again and all was good.

 

So what could it be? Im assuming its the alternator, but if it was toast, wouldn't it stay toast? Not be intermittent? Is there a charging relay? The fuse looks good. Ideas please people

[Mk4Gaz]

Check the wiring on the 3 pin plug to the alternator.

 

I had a bad connection on mine, which gave intermittent alternator failure symptoms.

 

I forget which pin it was, but I ordered a replacement plug, brand new off ebay, that came with new pins. 10 minutes with some wire cutters and a soldering iron, and all was good again

[Swampy442]

God call, i checked one plug and it pulled out easily, so I assumed that was the problem, but I put it back in and made sure it was secure. Ill do more digging tomorrow and see what I can find

[Swampy442]

Bumping this up.

 

Had the alternator repaired (regulator/rectifier) stuck it on, fired up on a spare battery, kicking out 14.5 volts. Winner I thought, put the original battery back on. 15 minutes of running time, minimal load (side lights) alternator stops charging and battery light comes on. Shit.

 

Put a known good battery in it literally 5 minutes later, fired it up and again, 14.5 volts. And again after 15 minutes it stops charging. All fuses good.

 

Urgent help needed as if its not don't by Sunday, Im not getting to work!

[Stephendjb]

Have you checked all the earth straps?

[TRD-1]

Sounds like it could be linked to the wiring Craig or a connector/terminal, fit in a temporary volt gauge so u can monitor the voltage as your driving to see if it stays around 14V or drops suddenly. Could be a break in the wiring somewhere or a weak connection to the battery.

 

If you have any heavy duty stereo wiring fit extra earth connections one for the battery and one for the alternator if that doesn't cure it then attempt to replicate the positive side wiring from the alternator to the battery and see if its that side.

Edited December 5, 2015 by TRD-1 (see edit history)