THE PROBLEM:
I put on an MPV Alternator on my S5, and now when I turn off the ignition and take out the key the car stays on for a second before shutting off instead of shutting off immediately as it has always done.

THE STORY:
I was in need of an alternator today and this shop I went to showed me a few alternators to choose from (cool place... CHEAP prices). So this guy said he could rebuild mine, or get another one. He showed me this Alternator that looked exactly like the one on my S5. The only difference is that the 2 prong wire plug is located on the back side (rear) of the Alt. So it almost touches the throttle body.
The guy said that this is Alt. is from a Mazda MPV (don't know the year), but that it is better because it pumps somethings like 90/95 Amps (unlike my 80 amps... i think). So I put it on ran it rof a while, and had no problems. But later when I turned it off, I noticed the problem. It shut of like one o those cars you hear in the parking lot when the guy is outside locking his door, and the car is still shutting off. Although my car did not stay on that long. Hmmmm. Any help?


I can take it back, no prob, but I like the fact that this Alt does pumps out more amps... maybe he can upgrade my old one.

 

I can't understand why that would be related to a constant running. Check ALL your Grounds.

 

I'm consulting more people.

 

You have the voltage input wire on the alt wired wrong.

 

would that make it back feed to the spark plugs, thus keep it running.

 

spark plugs would have nothing to do with it. They are not even in the same area- well alone on the same circuit.

The input for the alt regulator is hooked to 12V+ battery, instead of ignition.

 

Thanks for the info/help. I don't know much about electrical, so I need some help here. So Icemark how can I fix this? I know there are two wires that connect to my Alternator. One is a 12v+ that attaches (is held) with a nut. The other is a 2 wire "cord?" that plugs and snaps on to the top (rear in my case though).

Are you saying that the 2 on the "snap plug" may have to be reversed? Or is it something to do with the 12v+ nut held plug? (Don't think it's the 12v nut thing right?)

Thanks for the help.

 

the main single 12v wire with the nut will be right. only one place to put that.

the other 2 might need to be reversed. but I don't know.

Icemark check your PMs!

 

Sounds like the other two are reversed

 

Disconnect the two wires at the back, start the car, then shut it off. If the problem is solved, then that's where the problem is...

BTW, does anyone actually know what those two wires DO? I've forgotten (or perhaps, I just never knew).

 

I think you need to take it back to the company and get your money back. This is why:

I looked up 100 amp MPV units and they came out in 2000. They are all listed as "ED/IF". All others before this were 70 amp units. The "ED/IF" will not work on your car. "ED/IF" stands for "External Driver/Internal Fan". Your car came with a "IR/IF" - "Internal Regulator / Internal Fan".

The External driver style regulators use a field input Like the old external regulators. Basically, the MPV unit has a built in regulator BUT it uses a lead from the computer to control voltage output.

You are probably not charging your battery or putting 16+ volts to it ! Neither is good.

You need to take it back - They do not know what they are doing.

BTW, Aaron - The two leads are "S" and "L". The "S" is the battery voltage sense wire and the "L" turns out the light on the dash.


-billy

 

Thanks Bwaits. Your post has lead me to do a bit of research myself. I believe that that the alternator that I have come from an older MPV and is running at 70amps (yikes!) as you stated the the older one runs at. It is IR/IF though.

I'm going back to see if they can just rebuild my old one.. which I believe they have already done.

So to clarify, do you think that that switching the wires will do anything? Also, what happens if I'm running my S5 at 70 amps instead of the required 80 amps? How do you test how many amps an alternator is pumping?

Thanks for all you help.


Below are links to excellent pictures of the above mentioned Alternators -- the one I have, and the one I had.

(89-92 RX7 Alternator)
http://verizonsupersite.com/4alterst...7&catuid=12942

(89-98 MPV 2.6L & 91-94 MPV 3.0L Alternator)
http://verizonsupersite.com/4alterst...v&catuid=12942

 

It would have to be a 70 amp to work. The later ones would not. Here are the two regulators for the units.
You can see they label both the same with the "L" on top and the clip on the left. Check to see if you need to swap the wires. But, there is no reason to go through the trouble if they have built your unit. I would not leave it on there - it is lower amp. If it put out more than I could see a swap.

-billy


MPV - http://www.transpo.de/Catalog/Images/IM280.jpg
RX7 - http://www.transpo.de/Catalog/Images/IM277.jpg

 

https://www.rx7club.com/forum/attach...postid=1389325
One supplies a ground to a relay, which in turn makes the idiot lights come on. The other is from the battery.

 

alternator explained