My 427 SOHC Build..... Finally the time has come!

[jayb]

Just coming up for air after being immersed in my Drag Week project for the last couple weeks, and glad to see you have the engine running and the car driving.  You can expect some little gremlins like the fuse along the way, based on all the changes you have made to the car.  You just have to work through them one at a time, and eventually you will get all the little problems solved and the car will be a reliable driver.  Must have felt good to be back on the road!

[cobracammer]

Yes sir  lol  Feel better finding it was just a fuse.  I think where most of my issues are going to pop up is the fact that the saleens engine management system ( computer) controls many small "items" throughout.  Although the FAST ecu will keep the engine running, J will need to work around items I find not working because the OEM computer fritzes out not having many of the required sensors attached.  What has me thinking is why the FAST ecu was showing 7 volts after a good 20-30 minutes of driving.  The alternator should be recharging the battery, but it does not seem to be.  This may be something controlled by the OEM ecu?  I will do a few tests on therecharging jn the driveway, and maybe see if there is a way to wire the 3G alternator up so it directly charges the batterywithout relying on the ECU?  Definately great to be driving it!  Thanks again to everyone for the support throughout!!

[cobracammer]

Ok did some reading, and I think my 2 gremlins are connected.  Blown fuse and the alternator not charging the battery.  I have a 3 G alternator with regulator on the back.  From the ford wiring diagram, there seems to be an input from the OEM computer that connects to the regulator.  I believe this connection gives the alternator a signal to charge the battery.  Since my ECU is on the fritz given all the missing sensor inputs, i was curious how I can bypass any signal from tge OEM ecu so that the alternator will charge the battery without input from the computer. 


http://iihs.net/fsm/?dir=40&viewfile=Charging%20System.pdf

Above is a link to the charging systems diagram.  From what it seems, my 3G has a built in voltage regulator.  The original 6G relied on a voltage regulator inside the ecu.  I guess I really just need to know how to wire the 3 g on the cammer engine correctly.  Any thoughts?  This is what the seller said that I purchased from.

"this alternator has two wires, thin wire goes to the dash battery light.
or you need ignition power.
You need to run second wire from battery positive to alternator post 4 gauge wire"

What I had purchased was a wiring harness that makes a 3G Alternator connect in a car that originally had a 6G alternator (Like the Saleen).  This now seems like I have a 3G alternator with an external voltage regulator(on the back of the alternator) being fed through a wiring harness coming from the OEM ECU that has another voltage regulator(since the 6G alternators do not have a regulator- They are regulated from within the ECU......   Basically I just want to bypass the OEM ecu .  Any thoughts?

[cobracammer]

Found this diagram on the Factory five website.  What I can say is that I do not have a ground wire attached to the back of the alternator.  Would it have been possible that the original 6G alternator wouldn't have had a ground wire, but the 3G alternators need one?  I cant seem to find a clear answer to that online (and oddly, some of the wiring diagrams for 3G alternators don't show a ground wire either.

Thoughts?

[jayb]

That diagram looks like how I've got mine wired.  I don't use the ground wire since the engine is grounded, and the stud for the ground wire just goes right to the case of the alternator.  As long as the engine is well grounded, you shouldn't need to hook that wire up.  I hooked the yellow wire right to the big stud on the back of the alternator that the large cable also has to go to.  Then, ignition switch power to the green wire, which energizes the voltage regulator.

[cobracammer]

Thanks Jay.  I will just disconnect the pigtail from the OEM harness.  I will then loop the yellow power wire up to the power stud ( thick red power cable), and the run a fresh 12V signal wire ( hot in run).  Hopefully this will work and then 2 little gremlins handled.  Lol 

[cobracammer]

Ok.  Crawled under the car tonight.  In checking out the alternator, it was basically wired correctly..... "Basically".  The yellow wire was already looped back up to the power stud.  The white wire was plugged in correctly ( as shown in the picture above).  Finally, the pigtail connected the green "trigger" wire plugged into the oem harness which is linked to the computer.  I disconnected the pigtail, and ran a new wire from the infamous mini buss bar on the passenger side kick panel.

I then replaced the blown 10 amp fuse that feeds that same mini buss bar with "hot in run" voltage with a 15 amp fuse.  I now have all 5 spots on the buss bar occupied, but am nervous about guessing what amp fuse is large enough, but not too big to fry the wire or worse all the items connected.  Does 12v signal wires pull much?

Battery charger is on.  Will start her up on Saturday, check voltage at the battery while the engine is running. And then some more deiving!

[jayb]

That green wire should take very little current, probably less than an amp.

[cobracammer]

Thank Jay.  What I was trying to research online is this:  I have 5 accessories connected to the mini buss bar supplying power when the key is in the run position.  These are items like the FAST ECU, Fuel Pumps, Oil Pressure Gauge, Transmission Lock out Module, and now the Alternator.

I was wondering what would have caused the fuse to pop if these "signal" wires pull such a small amount of amps.  I saw that sometimes a drained battery will cause items in a car to pull extra amperage, but I don't know how reliable that source was...  and even if that was the case, with only 4 wires at the time connected, that's would have been somewhere around 2 amps?  I had a 10 amp fuse in there.  Any thoughts?  I replaced the 10 amp fuse that feeds the mini buss bar with a 15 amp fuse, but since I am not totally confident on electrical, was that the right move?

[jayb]

You said "fuel pumps".  Do you have more than one, and are these the power wires to the fuel pumps?  If so they will draw a lot of current, and that could be why the fuse popped.

If they are signal wires, so that they turn the pump on or off but the pump is normally connected to the battery via a large wire to get its power, then the current requirement would be low, and I would say you probably have an intermittent short somewhere, and that's why the fuse popped.

[cobracammer]

Hi Jay,

No you are correct.  There are Dual fuel pumps, however the power wires run directly to the battery.  The wire on the mini bus is just a signal wire to activate the pumps when the key is turned on. 

[cobracammer]

Ok, so I wanted to test the charge of the alternator.  Started the car.  Multimeter says the battery was 12.45 volts.  The FAST handheld says battery is at 12 volts.  Took the car for a drive around the block at which point the handheld says the battery was 11.8 volts.  Quickly pulled over and checked the battery which still showed 12.45 volts.  Unsure why thehandheld said that.  All in all, car was driving and at idle gor about 40 minutes and tye multimeter always read 12.45volts so I guess its charging

I did notice that pulling back into the driveway, the belt squeeled a little.  I think Ill tighten the alternator belt a little more before the next spin.  I took a video, but still awaiting its download onto photobucket!

[Barry_R]

Running voltage should be higher than that - more like 13.2-13.7ish.
You're not charging.

[jayb]

Barry is correct, Jason, you should have around 13.4V at the battery if the alternator is charging the battery. 

[cobracammer]

Hi Guys,

Alternator is wired correctly and with the 3G, the regulator is right on the back (built on to the alternator).  Should I run a new Power cable from the alternator to the battery?  I think in the Saleen, the OEM wiring runs the power cable over to where the starter is and then branches off to go back to the battery.  Starter works fine.....  not sure why the alternator is not charging the battery (since there are not that many wires).  Any suggestions?


Here is a video of the car running yesterday evening as well as each screen on the EFI handheld......

https://www.youtube.com/watch?v=X_VcqA0nFdM