Lots of work to do on the 720.

[None_zero]

So I started this as an attempt to smooth out the idle of the 720 which had begun to die at stops and seemed to be starved for air (Choke relay) I thought. I got the new relay for the choke and figured winter is coming it would be nice to have my heater blowing hot air again so i got a relay for that as well. Unfortunately last spring the old girl sat down on the side of the road and decided it was time for a break and in the ensuing madness of trying to coax her back on the road i ended up trying a big chunk of the wiring harness. I got most of it working again but have these issues remaining. No blower motor function wires not connected correctly, headlights are either bright or off no dim setting, windshield wipers only functional when lights are on...but we have degraded to wipers not functional on that one. 12v cigarette lighter is no go. I've got gas tank reading always full or always empty depending on the if it's odd or even how many times I've fucked with it. No speedometer (been that way since I bought it) the steering lock and ignition lock have been removed and there are a lot of deletions before she came into my care. She's not running her original engine. Came off the line as a z24 4×4 now she is sporting a z20 with a 4 spd trans 2 wheel drive. Never had a speedometer cable and I'm starting to wonder if this transmission takes one... anyways I've got a fuel tank float assembly on the way and a new speedometer cable which seems not to be OEM based on it doesn't have the right connection for the gauge got a couple new relays and a fresh desire to return as much of her functionality to her as I can with a very limited budget so anyone that just love solving puzzles jump in there and ask some questions I'll do my best to give you the clues. I cant even find a damn picture of the speedometer cable attached to the tranny that is helpful in locating it ....oh forgot to mention during all this I degraded to a no start condition which turned out to be the wire from one of the ignition coils was fried that's the second time that one has crapped out on me I replaced the coil the first time not sure why its doing that

[wayno]

One of the quirks of the 720 is the relay or some other devise behind the dash, in the rest position(no power to it) it is in the brights position, one of my trucks takes several minutes before will drop down to the normal head light mode, sometimes when I get tired of waiting I hit the steering wheel which shakes everything in the truck and it switches to normal mode, but that is after I am tired of waiting, you will find if you hit the brights it will not drop down again for a while, very annoying.

Not sure what is up with the headlights have to be on for the wiper to work, maybe it has something to do with the column key assembly missing.

4wd transmissions do not have a speedo drive in them, you will need to find a 2wd transmission  for the speedo drive to work as it is way too hard to explain how to change out the tail shaft of the transmission.

Do you have the fusible links anymore, they are right at the positive battery post?

[datzenmike]

The headlight relay is on the top of the fuse box on far right. It only has TWO choices on or off. In the off position the high beams are selected. To energize the relay the parking lights must be working. If parking lights are not on there is nothing to power the relay and it remains in high beam position.

 

wayno I doubt it's the relay and more likely the hi/low switch on the steering column. The lubricating grease gets dirty and thick with age. Try electrical contact cleaner and spray the internal parts.

 

4x4s drove the speedometer cable from the transfer case.  If you have the transfer case the cable is attached to it.

 

The engine or 'car number' on a 4x4 always begins with a Y just before the 720...

 

 

Does it still have the front differential in it???

 

[datzenmike]

8 hours ago, None_zero said:

So I started this as an attempt to smooth out the idle of the 720 which had begun to die at stops and seemed to be starved for air (Choke relay) I thought. I got the new relay for the choke and figured winter is coming it would be nice to have my heater blowing hot air again so i got a relay for that as well. Unfortunately last spring the old girl sat down on the side of the road and decided it was time for a break and in the ensuing madness of trying to coax her back on the road i ended up trying a big chunk of the wiring harness. I got most of it working again but have these issues remaining. No blower motor function wires not connected correctly, headlights are either bright or off no dim setting, windshield wipers only functional when lights are on...but we have degraded to wipers not functional on that one. 12v cigarette lighter is no go. I've got gas tank reading always full or always empty depending on the if it's odd or even how many times I've fucked with it. No speedometer (been that way since I bought it) the steering lock and ignition lock have been removed and there are a lot of deletions before she came into my care. She's not running her original engine. Came off the line as a z24 4×4 now she is sporting a z20 with a 4 spd trans 2 wheel drive. Never had a speedometer cable and I'm starting to wonder if this transmission takes one... anyways I've got a fuel tank float assembly on the way and a new speedometer cable which seems not to be OEM based on it doesn't have the right connection for the gauge got a couple new relays and a fresh desire to return as much of her functionality to her as I can with a very limited budget so anyone that just love solving puzzles jump in there and ask some questions I'll do my best to give you the clues. I cant even find a damn picture of the speedometer cable attached to the tranny that is helpful in locating it ....oh forgot to mention during all this I degraded to a no start condition which turned out to be the wire from one of the ignition coils was fried that's the second time that one has crapped out on me I replaced the coil the first time not sure why its doing that

 

The engine temperature and the gas gauge work off the same voltage regulator supply. Does the engine temp work normally????

[datzenmike]

drtfgyhjioku;[lp']

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[Charlie69]

English please!  LOL

[datzenmike]

oops trying to fix theee  e key. eeeeeeeeeeeeeeee every now and then ee instead of e 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[None_zero]

11 hours ago, datzenmike said:

 

The engine temperature and the gas gauge work off the same voltage regulator supply. Does the engine temp work normally????

Yes temp gauge works all the time. It usually warms to just below half. Gas gauge works but doesn't read correctly. The first time I removed the float (had to drop gas tank and clean it out. I was having to replace fuel filter monthly due to rust debris clogging it.) Part of the little coil assembly at the top where the wires connect to the float disintegrated and it hasn't worked right since. That's why I finally just broke down and bought one. I've tried to fix it umpteen times and it never works just goes from always empty to always full and back

Edited October 4, 2020 by None_zero

[None_zero]

Also I stripped out the flooring today. Anyone know where I can find that rubber matting that is laminated directly to the metal floor of the cab?

[None_zero]

I'm assuming the only option for the floor rusting out is weld sheetmetal over areas that need patching... anyone done this before or have any advice about it

[Draker]

2 hours ago, None_zero said:

Also I stripped out the flooring today. Anyone know where I can find that rubber matting that is laminated directly to the metal floor of the cab?

Lots of options. Fatmat, dynamat, generic eBay stuff. Some use window flashing but it’s asphalt based and may smell. The sound deadener material is butyl based and does not have an odor. You can buy it in different thicknesses.

[Draker]

2 hours ago, None_zero said:

I'm assuming the only option for the floor rusting out is weld sheetmetal over areas that need patching... anyone done this before or have any advice about it

cut it out and weld new metal in. I’m going through this process right now. To remove the sound deadening material use dry ice and isopropyl alcohol. Lots of examples of this on YouTube.

 

cut out the bad metal, weld in new. Here was my progress from today. Still have a ways to go until it’s done.

 

 

[None_zero]

Wayno and datzenmike im 100% sure the headlight issue and the wiper issue are wiring related both of them worked fine until i melted a bunch of the wiring harness together jacking around trying to bypass relays. I had to chase down and  cut out sections of the harness that were compromised and tie it back together. After that problems abound I'm certain I fucked it up during that whole process. I believe if i can get the right wires going to all the right places i can solve that stuff. As for motor and transmission the tag on the truck says it's a z24 4or with a fs5w71b. The plate on the block says z20 478808 and I know from driving it that it's a 4 spd... unless something is holding it out of 5th gear... so none of the info on the tag is right and cant find where a speedo cable would go on this thing. The speedometer didn't work when I bought it. The cable was never there for me to reference its location. 

[None_zero]

26 minutes ago, Draker said:

cut it out and weld new metal in. I’m going through this process right now. To remove the sound deadening material use dry ice and isopropyl alcohol. Lots of examples of this on YouTube.

 

cut out the bad metal, weld in new. Here was my progress from today. Still have a ways to go until it’s done.

 

 

Drake thanks for the tips I have very very limited experience welding and I'll need all the help I can get to get that done I'm sure.

[None_zero]

A couple photos I think the fusibles you mentioned wayno and the truck tag vs engine tag

 

https://postimg.cc/gallery/M11Gfx0

[None_zero]

While I was crawling around under the truck hunting speed cable connections and transmission leaks and oil leaks. You know your average run of the mill make more work for myself situation... I found a... port?? It's on the block low kind of between the starter and carburetor.. pictures attached..  what is that? Also included pics of o2 sensor dont know where that was ever connected and something under the carb that also had no corresponding connection for its harness

So this top pic is the 02 sensor on the front end of the block passenger side. It's never been connected since I bought the truck dont know where I'd hook it up. But I have a brand new one readybif I can figure its location for connection

 

This poc here is of the wiring harness of the piece that sticks out just below the carburetor. Pictured below looking kinda green.

Edited October 4, 2020 by None_zero

[None_zero]

This uppermost pic is of the unknown port which I'm thinking maybe was once attached to the a/c??? Truck has no a/c now if it ever did before 

 

Edited October 4, 2020 by None_zero

[None_zero]

Damn I'm struggling hard with these photos maybe its bedtime... lol

[None_zero]

Update, on the heater I pulled the switch just because why not everything else in the cab is dismantled... anyway the two black ends to the harness were fused together. I can see where the plastic casing around the red/yellow wire is charred a bit although it doesn't appear to be melted through and making contact with another wire 

 

At the other end everything looks pretty good except maybe the little plastic divider wall between the blue/red wire and the green wire seems a bit thin

 

Inside the switch was a little green with verdigras.. I cleaned it up. Thoughts on the wire? I guess I'll just replace it and see if that solves the issue 

[Lockleaf]

The photos Yolo provided do not show any 02 sensors.  02 sensors only exist in the exhaust manifold.  The sensor you posted slightly to the front of the oil filter is the oil pressure switch.  It turns on the oil light of your pressure gets to low.

 

I believe there should be a coolant line to that port you show behind the oil filter.  It has absolutely nothing to do with AC though.

[None_zero]

Thanks lockleaf that's helpful info where and to what should the oil pressure sensor connect to? Just straight to

the gauge cluster?

[None_zero]

Anyone know what this thing is?

 

Found it while doing some work around the front end... that's not stock is it?

[None_zero]

No one ever accused me of being the organized sort... lol bed is in the back yard got to find some one to help me lift it back on there once I finish with the gas tank.

[None_zero]

The first time I started this truck. In the backyard of some fellows house down in hermitage tn she said BAMBALAM before she started purring so I named her black Betty (because she was black, and that song you know) back then her windshield was held in with gorrila tape and she had a screwdriver jammed in her ignition. These days I call her Betty white. I love this truck. People have offered to buy it for well over what I paid ($300) but i wouldn't sell this truck with a gun to my head. I drove her home that day over a year ago now and I could feel her refusal to die. It resonated deep in the metal. I told her, Betty, as long as I'm alive you wont die, I promise. A lot of these repairs are well overdue but I've got some time on my hands and nothing much else that needs doing in hurry. I appreciate all the tips and info you guys share it makes it a boatload easier to figure which way is up when I get lost. Thanks.

[Lockleaf]

This is a shot of the passenger side of my z24 in my truck.  While the oil pressure sending unit looks different from yours (mine controls light and pressure gauge, not just light), this should give you the basic layout of what is found where.  Hopefully it can help you make sense of what you have going on, but I wonder if I mislabeled things in your original pictures.  

 

Is this a CA emissions truck or anything?  You have a sensor wired in to the coolant union under the intake manifold, which I'm not familiar with.  I have 2 sensors over by my thermostat (top right corner of pic).  One has two wires, one has one wire.  Do you have the same?  or do you have only one at the thermostat and one in the coolant union?

If you can take a photo like this one and post it, I might be able to give you better information about what is going on under there.

As for the wiring, I recommend finding a factory service manual for your year and getting the wiring diagram.  I am happy to help you read/trace wires through it, but that will be your best reference.