Fuel sending unit

[Patrick]

Just an update.

Turns out my fuel gauge is out of tolerance which I suspected all along because all the sending units I used gave the same erroneous reading. These are the readings taken with resistive loads:

Full-6 ohms
Half-18 ohms
Empty-30 ohms

Tanksinc doesn’t sell sending units with these values, or anyone else. Only the common ohm ranges are out there. With a simple calibration, I can have my ECM drive my out-of-tolerance gauge accurately. My measurements indicate that I can use a 13 inch unit from Tanksinc.

I thought about retrofitting to an in-tank fuel pump but decided to keep my external one from MSD. I don’t want another reason to drop the tank if it goes bad. I can replace my pump in a matter of minutes at the Walmart parking lot, lol.

In the future I probably will consider the Speedhut gauges. But the gps based speedometer is something I don’t like.

 

[Project86]

I have been using the Spectra unit without issue for 2-3 years. I also use the MSD 2225 external fuel pump with Dakota Digital gauges. DD has an option for a custom setting on the fuel tank unit. So you set it according to the sending unit. Mine was so close I didn't bother for the custom setting.

 

[Patrick]

Thanks for that information, @Project86. I’d never heard of DD and will surely see what they have to offer.

 

[Project86]

https://jeep-cj.com/community/threads/3rd-time-down-the-rabbit-hole.61116/

Some picts of my dash. I used a DD package made for a 40's Ford pickup. Enjoy.

 

[Patrick]

@Project86, you have resolved the oddity of the original “rear passenger facing” instrument panel on your rig. Very nice. Can you post a picture of the dashboard end result for me, sir?

The Speedhuts are a mere modernized replicas of the originals, while the DDs came up with their own arrangement. Both have their merits. If it was me, I would have placed them behind the steering wheel. Once there, the dials can be reduced in size with the traditional display oOOo.

I like the DD arrangement better, but I need to come up with a speed sensor somewhere. My Dana 44 axle has a provision for this, but I deleted the reluctor ring and threw it into the recycle bin a while back. Damn!

 

[Project86]

Here is a couple of teasers. I'll get a good picture tomorrow. Check with DD tech guys on your application for a speed sensor. I'm sure by now they have heard it all or most of it.

 

[Patrick]

Looks quite utilitarian and practical. You ain’t no purist! Kudos to you, dude.

Sure enough, their kit does include an adapter as shown on your image. I emailed them and they responded. Thanks again for the images.

 

[TSB8C]

If you're looking for something a bit more "purist", DD also offers a gauge set that mimics ths stock CJ style and fits the stock openings, but with all their fancy digital flair and some additional options. I opted for this package that looked more stock but includes a built-in tach. All their systems use the same digital control module behind the scenes. The kit also included all the sensors needed (oil, temp, etc) as well as the speed sensor in "project86's" pic. And their service is excellent. After about a year or so, the speedo quit working. Turned out it was the sensor. They sent a new one for free and a prepaid shipping envelope to return the old one so they could "autopsy" it and see what happened. Bright LEDs, white faces, all indicators (4WD, brights, turn, brake, etc), clock, tach, trip odometers, programmable speed (for custom tire size and gearing), and interfaces with a CAN bus if you have an ECU for the engine and/or trans. Mine's interfaced with the Edelbrock Pro-Flo 4 system for additional readouts in the LCD displays at the lower part of the main gauge.

 

[Patrick]

That’s some great info, @TSB8C. I do, however, would like to state my own product review on both brands. Of course, I haven’t bought them just yet, but this is based on their respective website description. I think they are too universal.

Let’s start with their tach. At 8k rpm, that gives my engine an extra 1.5k rpm’s. What a joke! The tach must be matched to the engine’s exact rpm range, or fall slightly short of that range. The tach should be marked with a red line, and it’d be nice if a bright red light comes on at red line. So, you really can’t “redline” your engine with their tach. The tach should also be marked with single digits and have a very wide needle sweep.

The voltmeter

It shouldn’t be a voltmeter, but a “charge” gauge. The gauge should be marked with a narrow “normal” area right in the middle of the needle sweep. Any other area in the gauge is a “warning” zone. A gauge marked with numbers (volts) gives the impression that any area is normal.

The oil pressure gauge

The same as the voltmeter applies here. It should be marked with a “normal” zone, no complicated psi numbers.

Temperature gauge

Pretty much the same applies here. No numbers, please. Only a “normal” and a “warning” zone. The calibration is key.

The speedometer

Keep it big, same proportion as the tachometer. Keep the numbers vertical (please lol) and do not skip from 20 to 40. Mark the 30 and so on. Limit the range to 100 mph or less, so as to amplify the needle sweep. We don’t go faster than 75 on our CJ’s. Ahem!

The whole idea here is that gauges should be more like warning indicators, not “current status” indicators. It should be very simple to incorporate a warning light and make it come on when the vital statistics fall to a marginal level. You just can never have it your way.

 

[TSB8C]

Well Patrick - to each his own I suppose. A few quick comments. I do like the "current status" type readouts myself. I prefer the volt meter, oil pressure, etc to show actual numbers. But that's a personal preference. On the tach topic and a "red line", these gauges do have programmable warnings you can set. And of course your engine type will determine where you need that red line warning. A stock 258 inline 6 would be different from a custom built Chevy V8 for example. So you can determine at what RPM a warning light and readout show up if you prefer. Programmable fuel readings for different tank sizes or sending units. You can also program a "shift light" that comes on to tell you where to shift gears and some other options. They are quite flexible actually in terms of options you can program. And remember they have a CAN interface if you want to include a BIM module to talk to other systems as well. So this further increases their flexibility. By interfacing into my engine's ECM, I get additional readouts and warnings in the main gauge display's LCD panel. Sort of like hooking a code reader to a modern car's OBD port, except this is built right into the gauge display and I can scroll through the various readings with a push button. And for warnings (high RPM, brake, volts, etc) those will automatically show up in the display without having to scroll through looking for them. Hate to sound like a DD salesman, but I do love these gauges, both in terms of functionality and also appearance over the old stock gauges. Nice and bright day or night. No more mechanical issues to deal with. Accurate readings. Programmable speedo for tire and gear changes. No extra gauges hanging under the dash to get additional features (tach, etc). All LED lighting. Sorry, rambling on again...

 

[Patrick]

I know, man. To each their own and I fully agree. To me this is a great exchange of information and you’ve gone to great detail. Thank you, sir. For now I have to fix my fuel gauge and the addition of a tach would be a great plus, not to mention one with a red line warning. I will take my time deciding. I do have an engine controller with a CAN bus, so that should make for a seamless instrument cluster integration. We’ll see.

 

[Patrick]

Guess what! These folks at DD can work with me with the cluster display style. Of course, for a fee. If the price is right, DD here I come. The child support is history and the rent is paid, but the CJ keeps on putting dents on the budget. Lol

 

[TSB8C]

Just
Empty
Every
Pocket

 

[Patrick]

Let alone the time spent on these things. Lol

 

[TSB8C]

Just
Expect
Every
Problem

Just
Eats
Every
Part

Jumps
Excitedly in
Every
Pothole