Stick in the Fan

[Marks481]

I've considered soldering all the wires to improve the connection, but I haven't done it.

I wouldn't. Soldering the wires tends to make brittle connections which can break after vibrating for a while. There is a reason why all automotive wiring is crimped.

That being said, all the terminals on my PT are cheap radio-shack variety single crimp connections, which are a disaster waiting to happen. I would recommend getting some marine grade (Ancor) wiring which is completely tinned for corrosion protection, and either using double crimp nylon insulated (designed to crimp on the wire and on the insulation) or heat shrink terminals. Either way gives you bullet proof connections which will last almost forever.

A quality ratcheting crimping tool is a must-have.

The wiring done on my PT is definitely of the haystack design. A little forethought, a common fuse block, and bundled wiring with protective sheath is on my project list for someday. Probably for the day after I get an electrical fault that disables my PT.

I like JJ's idea of the pushbutton start switch, but that would mean my 6yo would go joyriding on my PT, which would be a disaster.

 

[Charlie_Iliff]

Dear Charlie,

Alternators have this funny need of having a defined + & -, or they happily invert, and when they do, it tends to fry the regulator, since most alternators use a half wave rectifer instead of a full bridge.

I would definitely pull it and get it to a test bench to ensure nothing else fried.

I thought that you had installed multiple grounds. Did I miss something?
Peter

The defined + to the alternator seems to be the line from the "accessory" lug on the key switch. It also powers the fan and the flashing light. It seems continuous, with no shorts. I opened it and jumpered from the front pole to the back box and got the same problem, so the problem isn't a short in the tunnel. The back of the alternator has two 3-diode packs. The offending wire is on the opposite end of one pack from the main output (battery + lug on starter). When I disconnect that auxiliary wire, the engine runs fine, but doesn't charge. (I could probably have damaged something by doing that, but the symptoms are the same as before I started diagnostics.) The other diode pack has one wire tabbed to it. I didn't find what that was attached to, since I stopped looking once I was able to identify that the "auxiliary" wire was the problem.

Yes, I did run redundant grounds from front to back of the frame, and from the negative terminal to starter solenoid, but I didn't know about the one at the bottom of the junction box. It was a #8 machine screw with a locknut. To hold the roll, I had to use a roofing nail head held in the screw slot under the box. I didn't have many fond thoughts for the designer during that process.
I'm assuming it's internally regulated, although there was discussion on the board of a separate regulator on AV's 1850. I'll confirm with Terry.
Sedgewood: By mentioning the ground problem, I hoped to divert everyone's attention from my use of the 50 amp fuse. I'll probably never know the exact sequense of failure. Unfortunately, I'm leaving friday, so may not even get the altenator off until a week or so into August. Grass will be tall when I next attack it.

 

[woodlandfarms]

Kinda unrelated, but I was looking at my alternator on my 1850 yesterday and it has a big stamp on the side of it that says 14 volt - 60AMP. I thought for sure the PT was only a 30 AMP system. Man, if this is true my concerns about my light and other gadgets may be unfounded..

Oh and yeah, I cannot believe that the way PT has some of its stuff engineered. Connectors are crap, and the way the electric lays out is like the hydraulics. A real mystery...

Carl

 

[cqaigy2]

Oh and yeah, I cannot believe that the way PT has some of its stuff engineered. Connectors are crap, and the way the electric lays out is like the hydraulics. A real mystery...
Carl

Kinda reminds me of my old VW dasher.

All the great German engineering! Engine ran great, handle fantastic, but the electrical system was stupid.

Imagine having multiple loads with each being fed by their own + wire and having the whole works return on a single ground to a tiny little connector. Gold plated...but not big enough for the load. I ended up having to rewire the connection to the fuel pump ...etc.

 

[Carpenter]

This discussion is starting to bring back memories of my old MG and Lucas "home before dark" Electrics.

 

[KentT]

This discussion is starting to bring back memories of my old MG and Lucas "home before dark" Electrics.

LOL, home before dark, and pray it never rains...

I had a 74 MGB, and sometimes you'd turn on the headlights and the wipers would also come on. Sometimes you'd turn on the wipers and nothing would happen...

The mechanic I used specialized in British cars, and his only explanation was "Remember, the Brits have a strange sense of humor..."

We never found that "gremlin" the 3+ years I owned the car...

 

[Sedgewood]

Sedgewick, do you know the ampere rating on the PT switch?

Nope, haven't a clue but knowing PT's tendency to cut some quality corners I'd think a better switch is in order. For some reason I haven't had any trouble with mine from water or otherwise. Knock on wood.

When I rewired I went with a separate pushbutton start switch witch now has a high resistance gremlin somewhere and occasionally the starter solenoid won't pull in. Instead of diagnosing it I keep a short jumper handy and jump the solenoid to get going )

Sedgewood

 

[ponytug]

LOL funny on the british made cars with the quirky wiring. It brings back memories.

It also was my introduction to getting wiring right. Dielectric grease, good grounds, redundant grounds to panels, limiting the number of connectors...

I remember a friends MG that the wipers would come on when you turned on the headlights- sound familiar?- traced to a bad ground on the dash as I recall. When the lights were on, it raised the faulty ground enough to trigger the wipers.

Never thought I'd be using the same knowledge on a tractor...

Given the power layout, I have thought about pulling a larger guage power wire forward to minimize the voltage drop.

All the best,

Peter

 

[Charlie_Iliff]

Dielectric grease, good grounds, redundant grounds to panels, limiting the number of connectors...
Peter

And there was the time I completely rewired a boat trailer, that I had wired in the first place, mostly properly, because the trailer electrics acted strange on three different tow vehicles.
No change in symptoms until I fixed the bad grounds on a 1989 Chevy Truck, a 1986 Ford Van and a 1994 Toyota 4-runner.
You seldom go wrong looking for bad grounds. On my current problem, I'll bet the bad ground in the engine harness fried the regulator, diodes or both. I won't know for a couple of weeks, though. I'm riding a train to Montana, a rental car to Jackson Wyoming, and then return with a couple of days in Minneapolis. Maybe the PT will heal while I'm gone.

 

[BobRip]

LOL, home before dark, and pray it never rains...

I had a 74 MGB, and sometimes you'd turn on the headlights and the wipers would also come on. Sometimes you'd turn on the wipers and nothing would happen...

The mechanic I used specialized in British cars, and his only explanation was "Remember, the Brits have a strange sense of humor..."

We never found that "gremlin" the 3+ years I owned the car...

I bet that was a bad ground(s). The automotive rule of thumb is if the symptons are weird check your grounds. With the loads running I check the voltage drop between the battery and the ground on the device. Then move down the wire chain of the ground. A high voltage across a point (more than 0.25 volts) indicates something is wrong.