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Wedge TR8 Charging Voltage at 15.9

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The sense wire might be intact at the terminal and everything looks to be working correcting correctly. Before you do anything else, go check the main leads behind the down pipe on the oil pressure sender side of the engine, the wires usually burn and fuse together along that run.

Once they start doing that they will burn in two.

DSC_0003.jpg


No connection, over charge!

There is a service bulletin advising that you reroute the sense wire to the starter connection instead of to the battery line connector.

You can read what I have done here:
https://www.overhaulinforums.com/viewtopic.php?id=1533

Note that I replaced all the wires that go to the starter with heat resistant oven wire.
 
I, too, had to replace the wires on the passenger side between the starter and the oil pressure switch. The TR8 electrics were doing all sorts of strange things. I didn't use heat resistant oven wire, but I wrapped the new wiring with insulating tape and an insulated heat sleeve and covered the starter with an heat shield blanket. It would probably be worth your while to check out those wires.
 
OK, Ignition switch. Two things to check.

First, It is held in position by two tiny little screws. If they become loose, then the whole unit will turn when you turn the key.

Second, they have a plastic ring that carries the brass connectors. If that ring wears or breaks, then the switch will not align properly.

Also, there are four little plastic prongs that carry a brass rod that illuminates the "Brake" and "Handbrake" lights when the switch is in the start position. Those tabs are extremely easy to break off.

<span style="font-style: italic">(Now if you take the switch apart and everything works find, but once installed again, the switch refuses to turn to the "Start" position, then you have tighten the tiny screws to far and they are stopping the plastic ring from turning. Guess how long it took me to figure that one out!!)</span>

Next thing, if your car is a carbureted TR8, make sure that you have the oil pressure switch wired correctly. It sends power to the fuel bump. If you get the white/Orange and the White/Brown in the wrong place, it can send power to the starter when there is oil pressure.

When there is no oil pressure, the oil pressure switch is in the normally closed position. This completes a circuit from the White/Orange wire from the starter to the White/Brown wire to the fuel pump. When you turn the ignition switch, power goes to the starter through the White/Orange wire and then through the White/Orange wire to the oil pressure switch to the fuel pump.

When the oil pressure goes up, the switch closes to the normally open circuit. This sends power from the White wire from the ignition switch through the oil pressure switch to the inertia switch to the fuel pump.

There have been reports of the oil pressure switch turning on the starter when wired improperly. Also, remember that when the wiring harness burns through behind the exhaust manifold, that ALL those wire can fuse together, causing all kinds of havoc in several systems.

This one ill designed harness is the main cause of uninformed owners trashing the wiring in TR8s! When things go awry there, it causes several systems to go hay wire. This is why so many inertia switches and fuel pump circuits are improperly rewired.
 
If you split the wiring harness that goes to the starter, oil pressure switch and the alternator and send the oil pressure switch wiring and the alternator wiring along the body, then you will protect those wires.

DSC_0006%201.jpg


Here is the wires to the alternator and the oil pressure switch. There is only a single wire to the oil pressure switch because this is a FI car.

DSC_0003%201.jpg
 
Great feedback guys. I was going to crawl under there on Sunday once I have a couple of hours to devote to this.

I did the easy check on the ignition switch. I unplugged it form the harness. Radio still fires up without the keys in the car so the issue resides elsewhere. Could be in the radio after running it briefly at 16 volts.....

Clay....that is the cleanest alternator wiring job I have ever seen. Hope mine looks that good once I am complete.

Waiting on Sunday
 
Your wires have already been burnt through and someone has redone that wiring harness.

Your black wire is the sensor wire (originally small brown wire). I believe it connects to the small nut on the back of the alternator.

Your white wire connect to the small Brown/Yellow wire and goes to the ignition light at the top of the dash. It should plugs into the recessed lug on the back of the new alternator.

Obviously, the main charge wire goes from the big nut on the alternator to the large nut on the starter.

Your Blue wire on the oil pressure switch should be a White/Brown wire.

You can read the whole installation here:
https://www.overhaulinforums.com/viewtopic.php?id=1533

You can download the upgraded wiring diagram here:
Wiring Diagram
 
I read that entire write up and it is excellent.....

The DPO (me) re-did that wire harness many years ago and I am questioning exactly how well I did the job. I did re-route the wire behind the exhaust manifold.

My bigger question is whether that alternator I received from TRF is an ACR 25 or ACR 17. Thew back panels are completely different between the two.
 
There are several different configuration for that cover. I used to have several alternators laying around, but I have given them all away now.

I am not sure if the alternators for a TR7 are the same mounting configuration as the TR8. If they are, why not install a Saturn alternator. You will be a lot happier. Woody has sent me a new alternator set-up, but I haven't found it yet. I still have some boxes to open!

Replacing an Alternator
 
Is it possible that your radio power is hooked up to the cigarette lighter? The lighter is always hot, you know.
 
The Saturn alternator is an interesting thought....anyone else do that yet?

As for the radio....I do have the right wires, per the supplied diagram anyway, connected in the car. I checked for current on each before doing anything.

I was going to correct the alternator / battery issue and then trouble shoot the radio part afterwards.
 
i used an alternator off a 94 camaro. same alternator i think. have to change to a v pulley instead of a serpentine pulley. i mounted to the original tr8 alternator bracket with a couple bushings.
 
Went with that too.
My auto elec. bus. close to me did the pulley swap
 
If mounting of the GM alternators isn't a problem, they are good units. These are the alternators that Delco supplied after the SI series had run it's course. After the initial bugs were worked out, they proved to be very reliable, compact units putting out a ton of power. They (CS-130) have a four wire plug, but you only need two for operation, the sense and dash light.
 
F. Smith from So Cal (via the TR8 mailing list) may have made the right call on this I think. My car is a 1980 FI / AC car. These came with a 75 amp, A133 alternator. That's why none of the replacement alternators I have seen look correct.

I still think the Roadster Factory one is either a 20 ACR or a 25 ACR stuffed in a 17 ACR body. In either case it is not correct for my application.

Through all of this I ended up with an application list like this:

TR7 (all) = 17 ACR - 35 amp
TR8 Carb / no AC = 20 ACR - ___amp
TR8 Carb / AC = 25 ACR - 65 Amp
TR8 FI / AC = A133 - 75 amp

I think the direct cross over for mine (A133) is here courtesy of Gene Thompson: https://www.oreillyauto.com/site/c/detail...8&ppt=C0330

I am leaning towards Clay's Delco installation....96 amps is better than 75 and the install looks pretty clean. I stuck with the Delco 96 amp 8215 as it is a very simple, no bracketed change. The 106 amp from Woody is more expensive and more involved.

I'll have my old one rebuilt and put on the shelf should I decide to go concourse someday. I did the same with my starter when I switched to gear reduction.

Stay tuned....if I can get all the part collected after work today I may be able to install this on Sunday.

Thanks for all the feedback...this has been far more involved than I expected.
 
Just returned from the Electronics shop at lunch.

1. The new / fully rebuilt Roadster Factory alternator I received is dead :frown:

2. The 8215 is clocked wrong for a TR8. They moved the back plate and it looks better. Slightly smaller reach, but I think it will work. I'll find out possibly tonight.

3. They swapped out the pulley to a 2.6" v pulley in about 10 seconds...no big deal.

4. They bench tested the 8215 for me and it checked out at 105 amps. :smile:

5. the 8215 has a bat connection & four wires from the back.....they told me the connections are used as follows:
Red = sense
Brown #1 = Ignition
Brown #2 = Idiot light
Grey = tachometer

I assume that the four connections should be wired as follows for the TR8:
Red = Brown sense wire
Brown #1 = nothing
Brown #2 = Brown / Yellow idiot light
Grey = nothing

Does that seem correct? or do I need to swap Brown #1 & #2?

....sigh.... Still 105 amps versus what I think is 75 or less now will be nice once completed.

I'll share some photos & write up some details on this whole thing once completed.
 
That info on the wiring is correct. The order of the wiring is "PLIS"...it should be marked on the regulator if you look closely. It might show P-L-I/F-S. Some regulators were set up with a feedback instead of an ignition, hence the "F". Since they generally use the same casing for all the different regulators (probably 30 variations) in a CS-130, they are often marked that way.
P = Stator (Pulse, or tach)
L = Dash Light
I = Ignition
S = Sense

You need just the light and sense terminals for this alternator to work. The ignition terminal was used on cars that didn't have idiot lights, or they might have been controlled from the car's computer.
 
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