Mr_Rx7_Au

Hey Kent check out my pics.

I wired up the S term last night via a 20amp wire going straight to the positive post of my battery.

What is weird is I'm still only getting 13.2v.... where as before when my wires were the "wrong way" around, I was getting a constant 14v! (because it was always charging??)

Anyway, I'm testing tonight via a multimeter to see just how accurate my dash gauge is.

http://www.geocities.com/intercepter_05/alt1.jpg
http://www.geocities.com/intercepter_05/alt2.jpg

I also gotta put in a 30amp fuse tonight for the wire.

gsl-se addict

iTrader: (3)

Looks good. I am willing to bet the dash gauge is off just like mine is. Your voltage was probably too high before because the alt was putting out its full capacity at all times. Let us know what you find out.

Kent

Mr_Rx7_Au

Hey Kent, just another quick question to get my head around the system. What exactly does the B terminal do... isn't that the power for the alternator?

gsl-se addict

iTrader: (3)

The B terminal is the alternator output to the battery. The L terminal is for the alt indicator light in the dash and the S terminal is used to control the alternator output. I posted a pretty good link sometime ago about the operation of alternators, but I can't seem to find it at the moment.

H4Inf

I found my dash gauge under-reads by 1 volt, its been reading about 12.7, put the multimeter on and its 13.8 :-)

Mr_Rx7_Au

Hey Kent,

Here is my final setup

http://www.geocities.com/intercepter_05/final1.jpg
http://www.geocities.com/intercepter_05/final2.jpg

You can see my fuse holder with my 20amp fuse on it. Works a treat.

With the final 2 pic... my old s3 plug is just taped there with the splice to the L terminal. Because I'm still only getting 13.2volts, I was thinking of cutting off the old terminal and making it the one wire with the female blade to the L terminal instead of a messy splice.

The standard B terminal cable, should they be running to the battery positive as well? when I get home I'm going to trace that wire back and see where it goes. Where should it end up?

I tested with a multimeter and the dash reading is correct. Weird.

gsl-se addict

iTrader: (3)

The setup looks good. That voltage does sound low, though. It could be a bad connection. Hopefully the alt wasn't damaged running the wires backwards (I did see a guy on teamfc3s that killed his new FD alt running similar to the way you had it wired before). Here is the section on the engine electrical system for S5 cars. This should help track down the problem.

http://oregonstate.edu/~abelk/Manual...cal_System.pdf

It basically says if the load and unloaded currents are okay and the voltage is below 14.1 or above 14.7 (at 20 *C), then there is a problem with the wiring or a bad stator coil or diodes in the alt. You should be able to run most of the tests yourself. The only problem is that most people don't have an ammeter that can read 60 amps or more to perform the load test. If you have a local autoparts store or alt/starter shop nearby, you could bring the alt in and they will put it on their tester. I like to go to the alt/starter shops as they know what they are doing and can better tell you what's wrong with the alt instead of trying to sell you a new one like they do in the autoparts stores.

The alt output wire goes to the fusible links. You could measure the voltage at the alt output terminal and compare it to the voltage at the battery. If there is significant difference , there may be a bad connection in the alt output wire.

Good luck with it. I hope you get the problem solved.

Kent

Mr_Rx7_Au

Would it be possible to run a new wire from the fusible link to the b terminal.... like a whole new wire (like I did for the S terminal). Would it need to be a certain capacity cable?

The only thing I can think of now is that the B terminal wire is playing up. I'm pretty confident that it isnt the alternator because previously it was reading 14v fine, and when I did swap pins around without rewiring, it still was only at 13.2

gsl-se addict

iTrader: (3)

Sure, you could run new wire. The alt output wire splits at some point with one part that goes to the ignition switch and the other side goes to the fusible links (center link, [main], WR wire). I just put a 2nd gen fuse box in mine and did away with the old alt wire. I used 8 awg wire (not sure what that is in mm). You want a heavy wire, probably thicker than what is on there now. I am not sure what the easiest way to go about it with the fusible links in place.

You could trace the wire to where it splits and cutoff the part that goes to the alt. You could then run a new wire from the output post to the battery + terminal with an inline fuse. The fuse should be at least 80 amp. You may be able to find what you need (fuse/holder and wire too) in a car audio shop.

The other option is to get a 2nd gen fuse box. It will bolt right in (just need to bend the bracket a bit). You will also need female spade connectors (3/8", I believe) and a couple 5/16" ring terminals. You will have to cut the wires from the fusible links and add the needed connectors. You will still want to remove the old alt wire (where it splits) so that it doesn't short out with the frame. These fuse boxes are nice becuase they use common fuses and will have a couple unused slots for future upgrades.

When you checked the voltage, did you check it at the alt output, battery +, or both?

Kent

Mr_Rx7_Au

Thans in advance for all your input/help Kent.

I'm starting to think this could be a bigger job that I suspected to sort it out!

Ok, onto the post.

I traced my B terminal wire... it goes to the edge of the fender then it seems to go UNDER my batter tray into a hole somewhere. Is that where the fusable links are?

So the wire does come around and back to the alternator somewhere? I didn't see it do that!

I'm really starting to like the idea of a 2nd gen fusebox installed. Would the fuses inside replace the check relays as well as the fusable links?? what else would they replace? (would I have to chop and change the 1st gen fuse box under the dash at all?)

I just checked the volts at the battery +, not at the alt output

gsl-se addict

iTrader: (3)

I still need to trace that old output wire too and remove it. I don't have it connected to anything right now, but it is a hot wire and I don't want it shorting out.

On LHD cars at least, the fusible links are on the drivers (your passsenger) side strut tower. From what I can see on my car, the output wire goes over to the fender area, goes down (where it splts somewhere) and comes back up to the fusible links.

The 2nd gen fuse box will just replace the fusible links and make it easier to run a new alt output wire (still should remove the old one though). It won't change anything under the dash or anything.

This thread will show some examples of 2nd gen fuse box installations. The first pic Max7 shows is what the fusible links look like.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/fuseable-link-conversion-403676/



Check the volts at the alt output too if you get a chance. If the alt output wire is in bad shape, that may account for the voltage drop that you are seeing.

Kent

Mr_Rx7_Au

Once again Kent you are a star!

I'll go acquire a FC fuse box tonight. Should I just get the box, and no wires or anything?

I'll run some more tests over the weekend and then look into converting over my fusible links to the FC box with the fuses. Thanks for all your help again, I will probably need to post here again over the weekend!

Until then!

Cheers

Oh and GO SPURS! (yeah I'm a Spurs fan from Australia).

gsl-se addict

iTrader: (3)

No problem. Always happy to help. Go ahead and grab the fuse box, mounting bracket, the bolts that hold it in place, and the fuses. The S4 boxes use a 80 amp main like John64 is using. I went with a 100 amp main because that is what the S5 cars use. Either one will be fine. Your car is 12A, so you will have lots of empty spots open on the fuse box. In my -SE, I used 5 out of the 7 positions. You will only need 3 (headlights, retractors, main).

For the connectors I used five 10-12 ga. 3/8" female spades for the output wires (you can see them in Max7's pics), an 8 ga. 5/16" ring terminal for my 8ga. alt output wire, and a 10-12 ga. 5/16" ring terminal for the main output. I'm not sure what you will need in terms of a metric equvilent. Your best bet is to get the fuse box first and then determine what size connectors you will need. I will see if I can borrow a friend camera and take some pics of my setup this weekend.

Kent

Mr_Rx7_Au

Thanks kent. I've grabbed a fuse box for $30, with the bracket and bolts. I've got tons of fuses with all different ratings, now I'm just about ready to take apart my fusible link, label the wires, and proceed with the install.

BTW, the fusible links were on my left side inner guard.

Some pics of your setup would be appreciated. I'll keep you posted on what I'm doing.

gsl-se addict

iTrader: (3)

Sorry, but I don't have any pics of my setup. Mine is setup just like John64 (used thge 2nd gen bracket). In the link that I posted where I showed you the fusible links, there are some good pics of Max7's and John64's setup. Max7's pics will show you how the wiring should be. His is EFI, so his is using more spots then you will be. You will just have main (80-100 amp), headlight (30 amp), retractors (30 amp). The battery will connect in the center on the side where it is a solid bar underneath. Directly across (where you install the main fuse), you will have your main (heavy RW wire) and the new alt wire (both are bolted down with ring terminals). You will then need to cut and add terminals to your headlight and retractor wires. It is up to you where to install them in the fuse box, but I kept the same location as marked on the top of the fuse box (makes it easy to remember later).

I checked the output voltage of my S5 alt at idle to give you a reference point. I measured 14.29 volts at the battery and 14.35 volts at the alt output post. I may switch mine over like you did and run the S terminal wire directly to the battery with an inline fuse.

Kent

Mr_Rx7_Au

Yup, got it Kent. I'll be keeping the fuses inline with the markings on the box, just so I know what is where. I'll only have the 3, obviously. I don't need a pic of your setup, the link with Max7 and the other pics are fine. I'll be working on it tonight so I'll show pics when I'm done.

Thanks for the reference with the volts... after this install I hope to see some progress.

I have heard only good things about running the S straight to the battery +.

Mr_Rx7_Au

Update:

I purchased a new multimeter yesterday. The numbers:

Battery poles with both neg & positive terminals connected (car off)
12.34 - 12.40v

At the Alternator outpost: 12.30v

When the car ignition is on (ready to start): 12.20v

When the car is turned over and idled - reved to 2000rpm: 14.35v !!!! YAY!

When the car is off and alarm is on: 12.37v

My dash still reads at 13.2v....which is a problem, obviously with the wiring to that, but I'm glad to know my battery is getting charged at the proper rate from the alternator! damn dodgy multimeter!

So now I need to figure out, how do I fix my dash reading? how is it wired up? I had a look at the wires today above the pedals and behind the dash, and man, it's really messy under there.....

Oh, and I'm still installing the FC fuse box.

gsl-se addict

iTrader: (3)

I am glad that your alt apprears to be working okay. Was that voltage tested to the alt output or the batt? Either way it sounds about right. With regards to the voltmeter in the dash, it is probably the meter itself more than the wiring. I would just leave it. Mine reads about 1v low as well (shows as 13-13.5 when it is really 14.3 or so). You could always get an aftermarket gauge if you were worried about it, but as long is the gauge is consistantly off there is no need.

Good luck on the fuse box swap. Let me know if you need any help with it. It certainly doesn't hurt to replace these aging electrical components. I replaced my batt cables several months ago (Mazda ones $$). I'm really glad I did. The old cables had those crimp on connectors and the wire for the fusible links was always falling out. Also the cables would get really hot when cranking. Now it cranks much faster and the cables don't get hot like they used to.

Kent

Mr_Rx7_Au

The 14.35 was read on the batt. I'll go test the alt output again later today. But it does sound about right.

Yes, my voltmeter does exactly what yours does. Reads about 13.2 when I'm getting 14.35. And it does stay consistant. I know it's not a big problem but I guess I just want everything to be working the way it should be.

That is one thing I was going to do next as well. Replace both my negative and positive cables running from the starter motor to the battery. They are old. How much did you pay for the new mazda cables?

I also purchased a new set of magnacor ignition leads. http://www.magnecor.com.au/ really good quality.

Once again Kent, cheers for the responses. FC fuse box is starting tonight!

gsl-se addict

iTrader: (3)

The Mazda cables were like $53 for the + and $28 for the -. I know I could have just got some generics at the auto parts store for much less, but it is nice having ones that fit into place like they are supposed to. The cables that originally came with the car are aluminum, but the current ones from Mazda are copper (you can see the copper at the point where the neg cable attaches to the strut tower).

You can just get any quality copper battery cables if you don't want to spend the money for OEM. They will work fine. I just figured that they hadn't been replaced in 20+ years, so it is a small cost compared to everything else.

The voltage at the alt output post should be a bit higher than at the batt +. The difference should be small (mine was 0.06 volts different). A substantial difference between the two would mean a problem with your output wire having too high of a resistance.

Let me know what you think about the Magnacor wires. I have been thinking about getting some of those. If you look at the thread called "transistor trick for 2GCDFIS", you will see that I am building a circuit to interface the 1st gen igniter with the 2nd gen igniter and coil. I would like to replace my wires too and upgrade in the process. I have no idea how old my current wires are.

Kent

Mr_Rx7_Au

The Magnacor leads are fantastic. Them coupled with NGK-R spark plugs make for a great start and the rx def seems to eat it right up, so I'm very happy with them. The price wasn't too bad either, for what you do get. Highly reccomended.

I'm checking out that transistor thread now.

The main reason why I want to replace my battery cables are exactly what you said. No idea how old they are, they could well be 20 years! as far as I am concerned, that is more than past their retirement age.