Permanent fix (in progress): Fuel/temp gauge spiking (pics, not dialup friendly)

[Spook50]

Have my dash apart this weekend fixing some wiring issues (that I'm sure I was the cause of. Woopsy), so I did the chess board arm sweep across my work bench (alcohol may have been involved) and finally opened up my package of new PCBs for the project. The fit is still not PERFECT, but better than the last revision (which I'm running in my truck right now). I think I've finally reached a final design for the thru-hole regulators, and will be shifting two holes only about 0.005" just for the sake of getting a little more accurate, but I can consider the design officially finalized now, and will be assembling a handful of units to mail out for testing. You can see from the pics that the holes aren't 100% perfectly centered over the posts, but I can't imagine everyone's fuel gauge posts will be identical to the thousandth of an inch.

If tests come back good I'll be sending complimentary units to those who backed my GoFundMe when I first started this project. It's been a long time coming, but it's finally at the completion point. If the test units all come back with good reports I'll get the final revision of PCBs ordered and work on assembling units. I haven't settled on a final price yet, but at this point I can say they will NOT be expensive.

 

[Spook50]

Fancy new T12 style soldering station just got delivered today, which will help speed up the assembly process and reduce the chances of overheating components as I solder, compared to my ~20 y/o digital Radio Shack soldering iron. Need to make a couple modifications to ensure long term reliability and make it fully ESD safe, but once that's done it should be almost as good as a several hundred dollar HAKKO soldering station. Soldering iron stand and some no-clean flux are also on their way from Amazon.

 

[Spike Strip]

My $20 soldering iron just blushed.

 

[Spook50]

My $20 soldering iron just blushed.

This was actually less than my Radio Shack iron was when I first bought it, and a considerable upgrade, too.

 

[Spook50]

Okay my regulators with the larger diode (upgraded the diode from my previous design to allow for reverse voltage protection in 24V trucks) for some reason don't allow enough current output to move the gauges more than a quarter of the way up, so I need to take a closer look at the datasheets for the new and old diodes and see what the problem is.

This has also made me aware that I need a more in depth test bed for bench testing the regulators. With everyone's wiring being in various conditions the regulators still need to be adjustable, but as long as I can test the current output capability of any regulators that would tell me for sure if it'll work properly before installing in a vehicle. As it was, I set the output voltage on the new regulator, but with no indication (or suspicion really) of its poor current output, I couldn't see that it wasn't working until I had installed it in my truck. So I need to set up a bench test station that'll show me current output too. Meantime, back to the datasheets....

Edit: Found it so quick it's embarrassing that I didn't notice it before ordering the new diodes. The larger diodes have a forward voltage that's considerably less than the previous diodes, in combination with needing much higher forward current to reach that forward voltage. So while the Vout terminal of the regulator would show the 7.75V that I tune it to with my multimeter, it wouldn't even allow enough current into the switcher for it to move the gauge needles. Time to find a better solution.....

 

[poptart]

@Spook50 did you just come up the 7.5v for trail and error? I've been messing with my spare cluster and fuel level sender for the pass couple days on my test bench. Running my DC power supply through the integral voltage regulator I can't get the gauge to go above 1/2 a tank. My spare sender is the one I pulled from the tank (looked new) when I replaced it with a new OEM one from city racer. I measured and compared them and the ohms on both with the float all the way up and all the way down and they were within 1 or 2 ohms of each other.

Now I know I had some wiring issues on my FJ62 that could lead to some poor grounding for my fuel level sender dropping to empty with 1/2 a tank still left. And I won't know if I still have that issue until I get it all back together, but I'm waiting on parts for that.

With that said I still don't see why on test bench I'm only getting 1/2 a tank reading while using the regulator. I tried tuning the voltage regulator with no luck with the screw, but because of that now I can't say for sure what the output should be. I have a analog multimeter and a new oem fuel gauge on order. With an analog meter I should....hopefully, get some idea of the output volt of the regulator on a brand new gauge, versus a digital one that will just so the 12-14v spikes as the contacts close. I think I'm also going to try to grab some used gauges from my buddy that has a bunch from parts rigs.

Also, when connecting the DC power supply to the common post for the fuel and water temp gauge. I have to turn the voltage to ~10.5 to get a the peg to land near the full reading on gauge. Which had me confused, since you guys are using a lot less voltage than that.

Sender Spec were the following on my spare:
Full: 14.8ohms
Empty: 63.6ohms

I think my plan now is to wait for the new gauge to come in. I suppose be able to bypass the sender and run it to ground and vary the voltage in order to find out how many amps it takes to get it read full and empty. With that plus figuring out what the output on the integral regulator I should be able to calculate what the ohms actually should be for the sender at either reading.

 

[Spook50]

@Spook50 did you just come up the 7.5v for trail and error? I've been messing with my spare cluster and fuel level sender for the pass couple days on my test bench. Running my DC power supply through the integral voltage regulator I can't get the gauge to go above 1/2 a tank. My spare sender is the one I pulled from the tank (looked new) when I replaced it with a new OEM one from city racer. I measured and compared them and the ohms on both with the float all the way up and all the way down and they were within 1 or 2 ohms of each other.

Now I know I had some wiring issues on my FJ62 that could lead to some poor grounding for my fuel level sender dropping to empty with 1/2 a tank still left. And I won't know if I still have that issue until I get it all back together, but I'm waiting on parts for that.

With that said I still don't see why on test bench I'm only getting 1/2 a tank reading while using the regulator. I tried tuning the voltage regulator with no luck with the screw, but because of that now I can't say for sure what the output should be. I have a analog multimeter and a new oem fuel gauge on order. With an analog meter I should....hopefully, get some idea of the output volt of the regulator on a brand new gauge, versus a digital one that will just so the 12-14v spikes as the contacts close. I think I'm also going to try to grab some used gauges from my buddy that has a bunch from parts rigs.

Also, when connecting the DC power supply to the common post for the fuel and water temp gauge. I have to turn the voltage to ~10.5 to get a the peg to land near the full reading on gauge. Which had me confused, since you guys are using a lot less voltage than that.

Sender Spec were the following on my spare:
Full: 14.8ohms
Empty: 63.6ohms

I think my plan now is to wait for the new gauge to come in. I suppose be able to bypass the sender and run it to ground and vary the voltage in order to find out how many amps it takes to get it read full and empty. With that plus figuring out what the output on the integral regulator I should be able to calculate what the ohms actually should be for the sender at either reading.

Really it came from trial and error when dialing in the regulator once I started using an adjustable design. Once I had an accurate needle reading (calibrated based on what the fuel gauge showed with a completely full tank and checked against the temp gauge for redundancy) I measured the output of the regulator.

Given your wiring issues there could be a multitude of problems causing your gauge to be inaccurate. Bad wires, connectors, terminals, grounds, the gauges themselves (not as likely but it does happen with 30+ year old gauges) and/or the sender itself.

 

[Spook50]

I finally have space again! My family has finally moved into their new house and though we're still in the process of getting ALL the rest of their stuff moved, I've begun reclaiming what will be my work room downstairs. First task is improving the lighting with nice 48" LED "daylight" shop lights, then finish repairing the desk I bought to use as my permanent electronics station (some of you may have seen my thread about the desk lock in Chat). While I work on that during my off time, I've been better organizing my parts and supplies and am designing a test bed for both the regulators (that I described needing a few posts back) and another for the FJ62 driver's door relay boxes that I can now refurbish as well. Coupled with a new job that has me back in the electronics industry (telecom power management specifically), I feel like I'm back on track finally after a near 7 year roller coaster of more downs than ups.

As far as the regulator project goes, I'm looking for a US based PCB prototyping service since the one I used before had relocated their production from Germany to China (no thanks). Once I find one I'll get my next batch of PCBs ordered and tested. No big changes; just relocating the mounting holes for more accurate fit and enlarging all solder pads and the diode holes to accommodate the new diodes I intend to use.

 

[RenB]

I finally have space again! My family has finally moved into their new house and though we're still in the process of getting ALL the rest of their stuff moved, I've begun reclaiming what will be my work room downstairs. First task is improving the lighting with nice 48" LED "daylight" shop lights, then finish repairing the desk I bought to use as my permanent electronics station (some of you may have seen my thread about the desk lock in Chat). While I work on that during my off time, I've been better organizing my parts and supplies and am designing a test bed for both the regulators (that I described needing a few posts back) and another for the FJ62 driver's door relay boxes that I can now refurbish as well. Coupled with a new job that has me back in the electronics industry (telecom power management specifically), I feel like I'm back on track finally after a near 7 year roller coaster of more downs than ups.

As far as the regulator project goes, I'm looking for a US based PCB prototyping service since the one I used before had relocated their production from Germany to China (no thanks). Once I find one I'll get my next batch of PCBs ordered and tested. No big changes; just relocating the mounting holes for more accurate fit and enlarging all solder pads and the diode holes to accommodate the new diodes I intend to use.

Long time coming keep up the good work ! Do you have any idea when this will be in full production?

 

[Spook50]

Long time coming keep up the good work ! Do you have any idea when this will be in full production?

I'd hate to say, because I started this in 2013 and was planning on having it ready to go within a year at that point (reading through the thread explains the Cliff's Notes of why that didn't happen). Seems with every project if I utter anything like "I'm going to have this done by...." that just asks for delays. I'm in the process of converting the "craft room" here (just a non egress downstairs bedroom) into my work center for all my electronics projects, so once that's set up and ready I'll be able to get ramped up on supplies and production once I get a set of prototypes that are good to go.

I'm also trying to find a PCB protoyping house that ISN'T located in China.

 

[RenB]

I'd hate to say, because I started this in 2013 and was planning on having it ready to go within a year at that point (reading through the thread explains the Cliff's Notes of why that didn't happen). Seems with every project if I utter anything like "I'm going to have this done by...." that just asks for delays. I'm in the process of converting the "craft room" here (just a non egress downstairs bedroom) into my work center for all my electronics projects, so once that's set up and ready I'll be able to get ramped up on supplies and production once I get a set of prototypes that are good to go.

I'm also trying to find a PCB protoyping house that ISN'T located in China.

Patiently waiting for then! Got my gauge and a spare I’d love to do this to. God speed brüther

 

[CruiserTrash]

@Spook50

Some US-based PCB proto houses:
OshPark
Sunstone
Twisted Traces

I might be interested in an unpopulated board if you end up selling them. Heck, I'd be happy to test one for you.

 

[Spook50]

@Spook50

Some US-based PCB proto houses:
OshPark
Sunstone
Twisted Traces

I might be interested in an unpopulated board if you end up selling them. Heck, I'd be happy to test one for you.

I had a guy at my work recommend OshPark and Sunstone. Hadn't heard of Twisted Traces so I'll check them out too.

 

[CruiserTrash]

@Spook50 Amongst other things, OshPark is pretty popular in the DIY music community - people who are making small amplifiers and guitar pedals use them for proto work or small runs. Sunstone to some extent as well. Twisted Traces came up on a Google search and looked good.

 

[CruiserTrash]

@Spook50

Of course these places are going to cost more than a Chinese PCB fab house. I appreciate your effort to keep the supplier in the US though. FWIW I had boards made through JLC a while back - $10 for 30 small 2-layer proto boards shipped to my house from Asia. They came in 4 days. It was amazing - but they had several errors from the Gerber files I sent and I would likely go OshPark next time.

 

[ChaserFJ60]

I wish I had this before I bought my speedhut gauges! I miss my OEM style but with the speedometer and the fuel/temp gauge kicking the dirt I had to have some sort of monitoring.

I'm not sure if its been mentioned yet but why not make a PCB machine? Buy a cheap 3D printer and print a few already available parts from thingiverse and you can have your very own sweatshop in the comfort of your own home! The initial setup might be a a few hundo but once its setup you can keep production costs at a minimum. Not to mention you would have rapid prototyping capability which is a huge game changer for creating new products at a quick turnaround.

Theres a few different types of conversions that ive seen and this is only one of them.


If your interested in this route I would love to help out with the conversion if I could!

 

[CruiserTrash]

@ChaserFJ60 Is on the money. That's also prevalent in the small-scale, DIY guitar pedal world. The common complaint is that it's finicky to dial in. cutting depth doesn't have a lot of room for error, and they apparently track better when cutting at a 90* angle than around a smooth bend or a 45* (which is preferred in the PCB world).

 

[Spook50]

I wish I had this before I bought my speedhut gauges! I miss my OEM style but with the speedometer and the fuel/temp gauge kicking the dirt I had to have some sort of monitoring.

I'm not sure if its been mentioned yet but why not make a PCB machine? Buy a cheap 3D printer and print a few already available parts from thingiverse and you can have your very own sweatshop in the comfort of your own home! The initial setup might be a a few hundo but once its setup you can keep production costs at a minimum. Not to mention you would have rapid prototyping capability which is a huge game changer for creating new products at a quick turnaround.

Theres a few different types of conversions that ive seen and this is only one of them.


If your interested in this route I would love to help out with the conversion if I could!

I love the idea of machined/home printed PCBs, but I see those much the way @NLXTACY sees 3D printing: invaluable for in-house protoyping and DIY, but not something I would want to use for production of something I'm selling to the Land Cruiser community in support of my own Cruiser habit. I'll be checking out OshPark based on @CruiserTrash's recommendation and that of a couple guys at my work. I have a feeling, similar to your experience, I'll be going full SpeedHut within the next year. On the upside I'll still be able to retain my quad gauge to build into a test bed for the regulators during production, so that might actually make it a bit more convenient in the long run.

 

[ChaserFJ60]

I love the idea of machined/home printed PCBs, but I see those much the way @NLXTACY sees 3D printing: invaluable for in-house protoyping and DIY, but not something I would want to use for production of something I'm selling to the Land Cruiser community in support of my own Cruiser habit. I'll be checking out OshPark based on @CruiserTrash's recommendation and that of a couple guys at my work. I have a feeling, similar to your experience, I'll be going full SpeedHut within the next year. On the upside I'll still be able to retain my quad gauge to build into a test bed for the regulators during production, so that might actually make it a bit more convenient in the long run.

I wouldn't knock the idea too hard. The idea of something being 3D printed or made in house shouldn't diminish its value as long as the product does as advertised. 3D printing is a fantastic way to recreate/create new products that would otherwise be impossible for a low profile manufacturer like myself to bring items to market as I couldn't dream of starting my business with the high costs of CNC or injection molding.

I feel like 3D printers and all other machines that usually operate in the civilian world get a bad rap as they're mostly seen being used by those who enjoy making plastic toys and they get the same reputation as that of a toy, which for some they can be. But for myself a 3D printer gives me control over every point of production, which gives me the ability to use a material that is 10x more UV resistant than ABS and will probably outlast OEM plastic hardware. If one of my products fails I have the ability to make the adjustments needed to fix said failure and I can do so quickly without having to wait on a supplier. It gives me to opportunity to stock everything at once but to have it all contained within the space of a few High temp/UV resistant spools.

I would have the same views towards a diy circuit board, as a buyer I don't really care how the thing im buying is made as long as it works and looks good doing what it does. It's really freeing to know that I have nobody else to blame but myself when it comes to selling my designs.

I digress, I am looking forward to the circuit board and Im seriously considering reinstalling my old gauges given the opportunity!

 

[CruiserTrash]

@ChaserFJ60 I know your response is directed towards spook, but since I've got some experience with PCB prototyping, I want to jump in here.

You have great points - this stuff is easily possible to achieve on a DIY scale, and I firmly believe putting the power of production into people's hands at home is a good thing. The biggest difference that I see is that to go to a "pro" level in plastics is very expensive. Injection molding houses won't even have a conversation with you unless you're waving $15k at them. PCB manufacturing houses, by comparison have a much lower cost of entry. See above where I got a run of 30 small proto PCBs (of "pro" quality) for $10.

That being said ... my motto in life usually ends up being "DIY till I die". With that in mind, why don't we help spook etch blank boards with ferric chloride for a TRULY DIY approach haha!