Alternators and ecu/pcm help please

[james7]

I have a 2007 ford with an ecu/pcm controlled alternator which has failed a couple of times now. The most recent one has lasted a couple of weeks and maybe 250 miles at the most. The one before that lasted a bit longer but i was running the engine in so it did not get revved as much.
Both failed mechanically, the fans inside shattered and destroyed themselves.
The car is modified and now the alternator turns anticlockwise, rather than the original clockwise setup.

I can get a regular, ie non ecu controlled, alternator which should hold together and is designed to turn anticlockwise but was wondering if anyone had any ideas on how the ecu would feel about that ie eml light, limp mode etc

Thanks

[stevieturbo]

Why have you decided to install the alternator wrongly in the first place ?

Has any unit ever lasted ?

Lots of stuff currently available that is cheap.....are usually crap to start with. Presumably it was not an OEM unit that failed so soon ?

As for the ecu, you may get a check engine light if the alternator it expects is not present...but presumably you've already unplugged the control wires to check this and see if it poses any issues ?

[tapkaJohnD]

Many alternators today are fitted with "overrunning" pulleys, supposed to protect the alternator from crankshaft vibration via the drive belt. If you have set up the alt. to run in the opposite direction, presumably you have fitted a solid pulley, else there would be no drive to it at all. (I suppose you could reverse the overriding pulley!) So the alt. is exposed to crank vibrations, for which it is not designed, and they break the internals.

Pure guess!
John

[james7]

stevieturbo said:

Why have you decided to install the alternator wrongly in the first place ?

Has any unit ever lasted ?

Lots of stuff currently available that is cheap.....are usually crap to start with. Presumably it was not an OEM unit that failed so soon ?

As for the ecu, you may get a check engine light if the alternator it expects is not present...but presumably you've already unplugged the control wires to check this and see if it poses any issues ?

The alternator has to be fitted back to front after i added a supercharger. Theres not room to fit it correctly. It is a kit which is quite common, but i am overdriving the pulleys and revving it higher. With the standard crank pulley and low rev limit the previous alternator lasted a couple of years, but it was noisy and on its way out so not an ideal thing but nothing i couldnt live with.
Both failed ones are oe new units, rather than recon etc

With a failed alternator it has not put the engine light on but i have not revved it much either.
I was wondering what the ecu did with the alternator when it controlled it. All i can seem to find seems to be around smoother idling, starting and it seems to turn it off at full throttle for less engine load however im not sure if thats all it does as it seems like a lot of effort to go to for very little benefit.
I was worried i was missing something obvious, or not so obvious if that makes sense.

[james7]

tapkaJohnD said:

Many alternators today are fitted with "overrunning" pulleys, supposed to protect the alternator from crankshaft vibration via the drive belt. If you have set up the alt. to run in the opposite direction, presumably you have fitted a solid pulley, else there would be no drive to it at all. (I suppose you could reverse the overriding pulley!) So the alt. is exposed to crank vibrations, for which it is not designed, and they break the internals.

Pure guess!
John

I think you are correct! This is what i think is happening too.
It did have the overrunning pulley but the kit changes it for a regular solid one. Theres no way of fitting the overrun pulley with it the wrong way round.
The first one broke at santa pod when i changed gear quickly which imo points to what you have said above.

[james7]

Forgot to add....

Thanks for the replies

[stevieturbo]

Surely whoever tuned whatever ecu you are using could tell you whether it will be unhappy or not with a "faulty" alternator. ?

Although the fact so many are breaking....what exactly is the mode of failure ?

Electrical, mechanical ? Could be just a very bad installation, too much tension, poor alignment, other ?

OEM alternators should last a very long time. If the rotation affects cooling....try directing cool air to it. But surely everyone else with this "kit" isnt having the same trouble, otherwise it'd be a pretty pointless kit ?

[james7]

stevieturbo said:

Surely whoever tuned whatever ecu you are using could tell you whether it will be unhappy or not with a "faulty" alternator. ?

Although the fact so many are breaking....what exactly is the mode of failure ?

Electrical, mechanical ? Could be just a very bad installation, too much tension, poor alignment, other ?

OEM alternators should last a very long time. If the rotation affects cooling....try directing cool air to it. But surely everyone else with this "kit" isnt having the same trouble, otherwise it'd be a pretty pointless kit ?

When i spoke to them last time they were not sure what the ecu would think of a different one as they hadnt come across it before.

The mode of failure is the internal fan blades breaking off and coming through the case. I agree with what tapkaJohnD has said in his post as to the cause.

The alternator is now revolving much faster than it should due to pulley sizes plus increased engine revs revs.

Personally i think the reason others are not having an issue is the tuned cars in the us are mainly used for drag racing therefore are automatic so dont have the sudden rev drop which i think may be causing it with my manual car.

[GreenV8S]

I guess the pulley has a sprag clutch bearing in it. If you can dismantle the pulley far enough to get to that, you may find you can flip it.

I don't know how likely it is you'll find a standard pulley with identical dimensions and the reverse orientation. If you can't, these bearings are available off the shelf and perhaps you can find a local machine shop able to turn up a new pulley around one for you.

[stevieturbo]

I would highly doubt whatever users there might be for whatever engine this is....most likely a small 4cyl from your posts, and fwd...would be attached to automatic cars in the US for drag racing as the most common application.

Although as details are so vague overall...we're still guessing.

And what actual rpm's is the alternator seeing ?

[james7]

GreenV8S said:

I guess the pulley has a sprag clutch bearing in it. If you can dismantle the pulley far enough to get to that, you may find you can flip it.

I don't know how likely it is you'll find a standard pulley with identical dimensions and the reverse orientation. If you can't, these bearings are available off the shelf and perhaps you can find a local machine shop able to turn up a new pulley around one for you.

I cant flip it round as the new mounting position also requires an offset unfortunately.

I hadnt thought of getting a bearing i will look into that. Thanks

[james7]

stevieturbo said:

I would highly doubt whatever users there might be for whatever engine this is....most likely a small 4cyl from your posts, and fwd...would be attached to automatic cars in the US for drag racing as the most common application.

Although as details are so vague overall...we're still guessing.

And what actual rpm's is the alternator seeing ?

Close :-) Its a mustang v8, rear wheel drive. Most seem to be automatic for drag racing when they start to get a bit extreme which mine probably is classed as i guess.

What details would you like?

I had a brief work out at around 25000rpm alternator speed.
Also its quite a large diameter so things are probably moving quite fast in there. Also the fan is tin spot welded on so not exactly the most robust thing to begin with.

[anonymous-user]

james7 said:

I had a brief work out at around 25000rpm alternator speed.
Also its quite a large diameter so things are probably moving quite fast in there. Also the fan is tin spot welded on so not exactly the most robust thing to begin with.

er, the vast majority of alternators are rated at 18k max! So no wonder it's shedding bits! Lucky the rotor hasn't burst, and the field brushes are probably going to last about 10 min even if you swap out the fan for a billet one!

[tapkaJohnD]

So much for 'crank vibration'! 25K in an alt. designed for 18K max would seem quite enough to break them - that's a 30% excess on design criteria!

Many drag designs go thoru a COMPLETE rebuild after every run. If yours is that extreme, you may need to do the same.
John

[james7]

tapkaJohnD said:

So much for 'crank vibration'! 25K in an alt. designed for 18K max would seem quite enough to break them - that's a 30% excess on design criteria!

Many drag designs go thoru a COMPLETE rebuild after every run. If yours is that extreme, you may need to do the same.
John

Maybe crank fluctuation/drive belt fluctuation is a better way of describing it, which is when the overrun pulleys come into effect.
Which is why i think the autos dont have an issue as the revs are more constant compared to a manual.

Its a road car so nothing too extreme like that
However it seems to want an alternator rebuild after every run

[stevieturbo]

25k is far too high. Not a bit of wonder they're falling apart.

When Mustangs can be bought with a supercharger that has worked for years...without having to mount the alternator incorrectly....why does yours ?

[james7]

stevieturbo said:

25k is far too high. Not a bit of wonder they're falling apart.

When Mustangs can be bought with a supercharger that has worked for years...without having to mount the alternator incorrectly....why does yours ?

Theres 2 or 3 kits which mount them back to front, mine is obviously one of them.
Its a space thing basically, not enough room for everything. I guess its either compromise the supercharger or the alternator, something has to give.
The later models use electric pas so the alternator can live where the pas pump would have gone.

[Novexx]

Larger alt pulley to reduce rpm?

[james7]

Novexx said:

Larger alt pulley to reduce rpm?

Thats what it needs, but it wont fit with the standard alternator.
That was part of the thinking in going for a regular small alternator, i will have more room to move it around to fit a larger pulley in the space available.

[stevieturbo]

It seems hard to believe any kit for such a common vehicle in the US, would be so poor as to leave this very obvious problem.

Was it some ebay/china special or something ? Or something someone threw together themselves ?