Most troublesome car ever!!

[greyskull2]

Hi everyone, the alternator is the latest in a list of problems with my 2010 Avensis Estate T27 1AD-FTV. I think it's going to have to be a replacement unit but before that, is there a way to check that the fuse is intact before I have it changed. I believe there is a 100+ amp fuse on these or am I confusing with the earlier model?

These T27's apparently have a few alternator variants fitted so is there a definitive way to check which type I have without removing it? I can't see any marking on it when I look with a torch.

Many thanks and well done to those who are so helpful on here. I recently had sound advice from a couple of users even though I ended up having to take the car to Toyota MD's in the end.

[Mooly]

You should have direct connectivity (essentially zero ohms) between the Battery positive terminal and the main output terminal at the alternator. Typical DVM's will have a relatively high lead resistance so that will show in the reading, typically adding about 0.2 ohms to the reading.  

[greyskull2]

That will be the first check I carry out in the morning. Many thanks

[2009joe]

2 hours ago, greyskull2 said:

Hi everyone, the alternator is the latest in a list of problems with my 2010 Avensis Estate T27 1AD-FTV. I think it's going to have to be a replacement unit but before that, is there a way to check that the fuse is intact before I have it changed. I believe there is a 100+ amp fuse on these or am I confusing with the earlier model?

These T27's apparently have a few alternator variants fitted so is there a definitive way to check which type I have without removing it? I can't see any marking on it when I look with a torch.

Many thanks and well done to those who are so helpful on here. I recently had sound advice from a couple of users even though I ended up having to take the car to Toyota MD's in the end.

interested what other bother this car give you tbh dont think the 2010 2.0 d4d should give much bother at all plus with only about 100k miles on it. 

[greyskull2]

145k on the clock now and it has given all kinds of bother in recent weeks mainly with a combination of suction valve and injector issues. 

[2009joe]

1 minute ago, greyskull2 said:

145k on the clock now and it has given all kinds of bother in recent weeks mainly with a combination of suction valve and injector issues. 

would directly running into pump liqui moly diesel purge clear up the injectors wuld it i used to run that stuff into my vw 1.9tdi car was good stuff 

[Red_Corolla]

Test at the alternator post using a simple bulb to prove the circuit to the Battery is ok (engine off, obviously). Earth the test bulb on the alternator casing rather than at the Battery - that way, you're checking the earth strap as well as the positive lead. A continuity test won't always reveal a bad connection.

Keep in mind that modern charging systems are usually ECU regulated using a signal wire connected to the alternator. The fact that it isn't charging doesn't always prove the alternator itself is to blame.

[2009joe]

1 hour ago, Red_Corolla said:

Test at the alternator post using a simple bulb to prove the circuit to the battery is ok (engine off, obviously). Earth the test bulb on the alternator casing rather than at the battery - that way, you're checking the earth strap as well as the positive lead. A continuity test won't always reveal a bad connection.

Keep in mind that modern charging systems are usually ECU regulated using a signal wire connected to the alternator. The fact that it isn't charging doesn't always prove the alternator itself is to blame.

on my 1.9tdi one time i got a rectifier (brushes) on eBay for my alternator and put them in i think should be a easy job but not sure if toyota alternators go out at that many miles could be wrong thought they should last longer before problems start 

[greyskull2]

Update

Hi, I have proved continuity of the heavy charging lead - not even 0.1 of an ohm resistance.

I have 12v between the charging post and alternator body.

The 4 pin connector on the alternator looks clean and is seating well and has been doused in electrical cleaner before re-fitting the plug. Testing from ground to the 4 pin plug I have 11.4v on one terminal and full 12.7 on another. The other 2 terminals are zero - assume ground and possibly an ecu signal wire???

I still have the red warning light on the dash and no charging of the Battery.

Conclusions - dead alternator or a complex earthing issue.

The problem is when I've spoken to alternator suppliers they all say the same thing - THEY NEVER GO. This causes me concern.

Any observations from the good people of this forum please?

[Mooly]

The main grounding is via the alternator metalwork being bolted to the engine and then from there back to the Battery. So the alternator body should have a similar 'zero ohms' connection back to the Battery negative.

With the engine running there should be no volt drop between the Battery negative and the alternator metalwork.

9 hours ago, greyskull2 said:

THEY NEVER GO. This causes me concern

I'd take statements like that with a pinch of salt. Never is quite a sweeping statement.

10 hours ago, greyskull2 said:

Testing from ground to the 4 pin plug I have 11.4v on one terminal and full 12.7 on another.

Have you actually measured the voltage across the battery terminals with the engine running? 12.7v suggests a fully charged battery. What voltage do you see with the engine running, and what do you see with engine running and headlights on?

The output may be low but it may still be generating some power.

 

[Parts-King]

If you PM the registration of the car, I can tell you what alternator it should be. You need to do it before midday today as I am outta here after that

It depends on a few factors as to the amps of the alternator, most are 100 amp, some 150 amp

 

[greyskull2]

Hi guys, further update after carrying out the above recommended tests;

engine off - 12.6v, engine running - 12v, engine running, loads applied - 11.5v and the Battery will drain completely if left in that state.

Earthing straps removed, cleaned, re-attached. 

Alternator is Denso 104210-4521 or Toyota 27060-0g011

[Mooly]

That's conclusive that it is not charging. I think a suspect alternator has got to be favourite. Ideally you would need to identify what all the leads do electrically and then determine if the correct conditions are in fact present. By that I mean if the alternator is a type capable of being controlled by an external signal then determining that the alternator is not in fact being told to produce no output would be the next step but ask yourself how often that kind of in depth fault finding is needed... the majority of issues will be just a duff alternator.

The only other practical advice I could give is that given other problems you have mentioned, is it possible something has been cut/crushed/damaged etc in the wiring loom to the alternator while other work has been carried out.

 

[Red_Corolla]

If it's got 4 wires then I would bet one of them is a PWM signal from the ECU. Other 3 will likely be (1) the field supply (ignition switched and separately fused), (2) the voltage sensing wire from the Battery (separately fused and permanently live) and (3) the charging indicator lamp (should be fine as long as it's working on the panel).

Remember to check that the main connections are in fact good. Continuity tests are no good on power distribution circuits, use a test bulb or do a voltage drop test with the car running. Battery positive to alternator post and then Battery negative to the casing. Both should be 0.2v or less.

[greyskull2]

Thanks guys, great input, new unit required by the look of it. Ive seen a great priced new copy unit for sale from a company in Huddersfield so go for that I think.

My only concern now is the drive shaft removal - has the procedure been discussed on here previously, can't see it when I search. I would like to keep the gearbox end in place while changing units if possible - any thoughts please?

I hope everyone had a good day yesterday, all the best to you.

[Red_Corolla]

On 12/26/2021 at 1:07 PM, greyskull2 said:

Thanks guys, great input, new unit required by the look of it. Ive seen a great priced new copy unit for sale from a company in Huddersfield so go for that I think.

My only concern now is the drive shaft removal - has the procedure been discussed on here previously, can't see it when I search. I would like to keep the gearbox end in place while changing units if possible - any thoughts please?

I hope everyone had a good day yesterday, all the best to you.

I don't know the Avensis, but I'm guessing that if the driveshaft obstructs removal of the alternator, it's probably the inboard section between the gearbox and inner CV that's in the way, in which case you would be looking to remove the whole thing. Best to have a look underneath and see what space you have to play with before starting.

Sounds like a pain of a job just to change an alternator - I haven't done one myself since the good ol' days when they mostly came out from under the bonnet! 😊