MD Juan Tub Kit 1969 CJ5 4CLY (7/2016)

This is about to look very familiar... I got a 3rd (!!!) replacement gage from Oconee off road, a sales outlet for Omix-Ada and Crown. After Omix-Ada fell down 2x times, Oconee went to crown to get me a working speedo mounted fuel gage.

Those with experience here saw this coming, but I did not... Omix-Ada and Crown fuel gages are made by the same manufacturer. So, no surprise then that example #4 is every bit as bad as its three predecessors.



I've gotten 4 of the identical same gages from two aftermarket suppliers who sold these under two different company names and every one of them has been defective in the same identical way. They may be serviceable... don't know yet. Will let you know.

 

Fuel gage update. Oconeeoffroad.com gave up... their 2 suppliers for jeep cj speedometer mount fuel gages, Omix-Ada and Crown, we're unable to deliver any functioning fuel gages in 4 attempts... wow! They just sent me a refund (so I would go away, I think). They said to not return the gages, "just throw them away".

I'm going to try and fix them and share the attempt here.

 

I don't know how useful the following is, but for the record, I compared the behavior of 5 jc5 speedometer mount fuel gage, one(1) was NOS and four(4) were after market all likely made by one company (name unknown) but sold under the brand names Omix-Ada and Crown. I bought one(1) from Quadratec, and three(3) from OconeeOffRoad.com.

The NOS gage (Stewart Warner) seemed to operate properly. I have yet to test it with the float level sender.



The four(4) aftermarket gages appeared identical to each other in every respect. I opened one each of the Crown and Omix-Ada to compare their internals... they were identical internally also. But they differ significantly from the NOS gage in several ways. (Note, do not attempt to ground the gage case via the adjustment screw access hole in the gage side... If your ground clip touches the screw, it will short out the internals.)

The first of the four aftermarket gages initially would not produce a reduced (average) voltage at terminal post "A" ("A" feeds a reduced average voltage to the speedometer mounted oil coolant temp gage). An internal examination revealed unwanted contact between two internal current carrying parts (i.e., a short). By mechanically deforming some internal parts I was able to eliminate the short, which repaired the voltage reduction function, but I could not calibrate it (an oscilloscope or high quality voltmeter might be best for this).

All four aftermarket pointers were displaced rotationally from their correct alignment, ("correct" probability means parallel with their visible white pivot lever). The displacement was well past the metal "stop" built into the gage face, and seemed to me sufficient to deform the internal bi-metal driving lever. The one gage I tested was displaced so much that a "Full" tank signal was not enough to move the pointer away from the metal pointer's "EMPTY" "stop" tab.

They were deformed so much, that none properly read "Empty" when the pointer was realigned on the pivot pin back in line with the white plastic pivot bar. They may work fine with some initial rotation (say, to "zero" the pointer on the dial) but not with as much pointer rotation as they had.



I tested the remaining three(3) aftermarket gages. All three of them cycled internally to produce a reduced voltage on terminal post "A", but my equipment was not good enough to report the average voltage produced.

I'll provide an update when I attach the float lever and cycle all the gages between full and empty level signals.

 

Howard;

Thanks for mentioning that. I do appreciate these aftermarket (and NOS) gauges provide holes for internal adjustments. From an examination of the internal parts, I could see two places to make adjustments via holes in the back of the gauge case, and a third to change the voltage reduction via a screw. The holes in the case allow for changes to both "Zero" and "range" or "span". I see that one rotates the mechanism which also rotates the pointer towards the "Zero" stop. And the other displaces the mechanism so the bi-metal drive arm pin engages the slot in the pivot lever either closer to, or further away from, the pivot. Closer to the pointer pivot increases the multiplication of the bi-metal drive arm movement (larger span), further away decreases the movement multiplier (smaller span).

It has been my experience (in other calibration work) that I if you adjust one, you nearly always have to adjust the other. Since I didn't have the float level sender set up at the time, I didn't attempt to make the Zero and span adjustments. I relied on pictures from only a few available sources which suggested to me that the aftermarket fuel gauge pointer most likely was intended to be in line with the white pivot arm... but that is only a guess.

I also have seen on a few occasions other gauges allowing you to rotate the needle on its shaft to set the Zero. I couldn't see any obvious reason not to make a Zero adjustment via the pointer position on the shaft, except either to avoid making it loose (by moving it too many times), or to avoid stressing the internal mechanism by torquing the shaft when rotating the pointer. Actually, I was surprised to see an internal zero adjustment on these gauges... Perhaps they borrow components from another gauge, or perhaps they have so much manufacturing slop that they require more internal adjustment to make them usable. I can only guess.

I have not been able to determine if they all suffered identically the same shipping damage or if they all suffer from the same manufacturing errors, or both... If their terminal's nuts had been run up to sandwich the cardboard packing support they would have been "fixed" in their shipping container and the needle would have been protected (by a second cardboard insert) from impact with the shipping box sides. But that didn't happen. The gauges were all loose and free to slam into the shipping box which likely displaced the pointer and bent the "stop" tabs (in addition to any manufacturing defects masked by the shipping damage). Bottom line is that no one on that end seems to give a hoot about it. ("Hoot" pun not intended, Howard.)

But for our purposes, if the internals have not been damaged (and shorted), these aftermarket fuel gauges appear to be easily fixable if you have a gentile touch, just a bit of knowledge and some patience.

The shorted gauges are also repairable, but maybe not without then adjusting the average reduced voltage at terminal "A". Adjusting that voltage screw properly likely takes some good electrical measuring meters which the average guy might not possess.

 

I have been following your thread with interest, especially your work on the fuel and temp gauges. I have a 1964 CJ3B and the cluster mounted fuel and temp gauges do not work. Previous owner installed a manual water temp gauge and aftermarket fuel gauge. Unfortunately, he cut holes in the dash to mount the aftermarket gauges. I would like to restore the original cluster gauges and repair the holes in the dash. I have done nothing to the old gauges at this time, but did purchased an old, used cluster that I took apart to try to understand how the gauges work. I was tempted to order the reproduction Omix-Ada gauges, but after reading your posts, I understand that would be a waste of money. (thanks!) I do have a couple of questions. Since the voltage regulator is in the fuel gauge, when it fails, do you find that the water temp gauge is also damaged? Have you considered using an external IC voltage regulator to supply the 5 VDC to the gauges? Thanks.

 

{editorial note: 2021/11/2 I did end up getting an external electronic voltage regulator, removing the 12 VDC supply, and wiring it to the shared (low voltage) center post on the back of the fuel gage.}


Hey, Chuck, thanks so much for your note.

Yeah, Joe and I decided to close the extra gage holes in our dash, too, and to put some time into making the speedometer cluster work properly... so I think we get where you are coming from!

I'm a retired mechanical engineer with some electrical savvy, but I'm not an expert. I've picked up some good stuff from Howard in this post and searching EarlyCJ5.com. Unfortunately a lot of the older posts have broken links and missing photos, so the older stuff while still good, isn't maybe as good as it once was.

I eagerly invite challenges since I'm making up the following based only on what I've read, but these speedometer mounted gages seem to fail mostly due to bad grounding.



This is the (dead) gage that came with my Jeep a year ago. Both heating coils were burned up... I haven't noodled out why the voltage regulator heater wire would burn up... it is designed for 12VDC... hmmmm... I need to sketch this entire fuel gage circuit so I can "see" it more logically. Maybe I'm missing something. I'll share it when I do.

Edit: I sketched out the speedometer gage circuits here:



Fuel gage left, temp gage right. Float sensor lower left, coolant temp thermister (I guess) lower right. Voltage regulator center top. Regulated voltage bridge between the two gages is the A-A jumper. The fuel gage case ground is in the upper center.

Edit: When I sketched out the voltage regulator circuit I realized its heating wire sees regulated voltage only (duh..., sorry) and NOT a constant 12 VDC. But I still don't get why/how losing fuel gage case ground would contribute to burning up the heating wire. With the regulator heating wire, no ground = no current = no heat. Hmmmmm... still stumped on its failure mode. The regulators contact points would have to stick closed or the voltage output be adjusted too high... or ... I don't know what, to burn out that regulator heater wire.

In this photo, the "I" post (12VDC power in) is at 4:00, the "A" post (avg 5VDC regulated internal, and external to temp gage) is at 1:00, and the "S" post (to ground via fuel level sender) is at 10:00.

They rely on the back of the gage contacting and grounding to the cluster housing, which has to make good grounding contact with the dash, which has to make good contact with the body, which has to ground to the frame, which has to ground to the engine, which has to ground to the battery... If the fuel gage cup doesn't have a path to ground, then the voltage regulator doesn't cycle and 12VDC (instead of an average 5VDC) is fed to the wrapped wire heating elements on the bi-metalic gage pointer driving mechanism, and is fed through the resistance coil in the fuel level sender. 12VDC quickly burns up the internal pointer heating elements (and the fuel sender coil !, or so I've read). (I added a ground wire direct from the battery to the dash and then to the cluster housing... 'still not perfect.)

It is hard to imagine how the gage cup to speedometer cluster housing grounding contact can survive without corroding over time, so in my view 100% of these will eventually fail without intervention (i.e. intervention like adding a permanent ground wire to the fuel gage cup).

Certainly, a more reliable voltage regulator that didn't depend on the fuel gage cup being grounded is a viable alternative. I'm unable to look at the open gages at the moment, but from memory I'm going to guess you would not power the "I" post at all and just take your regulated 5VDC power to the "A" post. The "A" post internally feeds the fuel gage pointer circuit and externally feeds the temp gage circuit.

It seems to me you would also want to insulate the fuel gage to prevent it from grounding (!), so that your regulated power on the "A" post doesn't feed backwards through the internal voltage regulating circuit to ground. I can't see that it would actually hurt anything to leave it as is, but it would heat up a bit and draw a bit more power than otherwise needed from your regulator circuit.



In this photo, the "I" post is at 11:00, the "A" post is at 9:00, and the "S" post is at 7:00.

After taking a second look at my photos, I have more confidence that my "guess" above is correct.

I think my closing comment should be that I think the aftermarket fuel gages are probably usable (usually with minor adjustment), and maybe not a complete waste of money. I was even able to restore the one with an internal short in about 15 minutes without damaging it, and before it burned up. The formal zero and span adjustment needs to be made with them well grounded, and out of the cluster, and using an uninstalled fuel level sender (or easier, using resisters as Howard suggested). With luck, only the pointer position might need to be rotated, and that is a cinch. Yes I'm deeply disappointed that the manufacturer and suppliers sell defective products which could so easily be delivered in top condition... But at least we have a source (crappy as it is) if we need one.

PS I saved my burned up original fuel gage. Its heating wires are burned up. I hope to revisit re-wrapping the bi-metalic pointer drive and voltage regulator bars using heater wire from one of these aftermarket gages... But then again there are lots of things I'd like to do .

 

I just got a big surprise when I went to my local mall to get some resisters at Radio Shack... no Radio Shack! 'Don't know if they are gone everywhere or just locally. Man... what are we "geeks" going to do without a Radio Shack?

EDIT: Radio Shack just closed about 1/3+ of their stores, about 1000 remain. I think they are doomed. I did find a few left across town.

 

No Radio Shacks left in the county I live in. We had a real good local electrical gadget place (scanner crystals, diodes, etc) in Akron but when I went looking for a diode for my generator they were closed too.

 

On line.... resistor, $0.12 , shipping, $7.00 . (I made that up but i won't be surprised if true.)

 

that looks like fun. The last time I did that much soldering was 1972 when I built a Dynaco amp and receiver!

 

Thanks. At this point, I will probably relocate the two aftermarket gauges to an under-dash mount so I can go ahead and repair the holes in the dash. I'll keep watching the forums and hope that someday someone will produce a better gauge set for these vehicles.

 

Mine had a three (3) gage cluster hung below the dash. I saw so many of these in Jeep photos, at first I thought they might be a stock accessory... nada.




I was going for as authentic a layout as I could afford, so I ripped them out. It has been a struggle getting every thing in the speedometer cluster working... actually we aren't quite there yet... but we think it's worth it for what we are after.

I also thought the below dash gage cluster gages were too small to read... but my eyes seem to get weaker by the week.

 

Has anybody followed up on this on the CJ3B page? Jeep Fuel Gauge Tech Tips on CJ3B.info
"Greg Wilkens in Australia installed VDO instruments inside the original cluster (left) on his 1958 CJ-3B. He also added a protective rear cover (80K JPEG) that helps organize the connections."

 

Fancy!

 

Back in the saddle again but light Jeep day: no Joe, late start.

Well, first off I checked the accuracy of my fuel gage by using my new aftermarket fuel level sender. It worked great. Full and Empty displayed at the two extremes of the float movement... which may only approximate the actual tank Full and Empty positions, but that's close enough for my needs.



Next, I installed the PCV valve.



The hose shown coming off the rocker arm cover vent (2:00 position) gets routed to the left (from this perspective) and down to PCV valve mounted on the right (passenger) side of the engine, above the distributor. (See next photo). The hose barely seen at left center is connected to the oil fill tube (cap just visible) and is routed to a port in the oil bath air cleaner housing. (See next photo).



The PCV valve is just left off center, and the oil bath cleaner port is at about the 7:00 clock position. I had made a piping mistake (before I realized I needed a PCV valve) and I added a "T" to the hose between the oil fill tube and the oil bath air cleaner. That's what all that hardware is in the middle of the photo. Until I get another length of vacuum hose, I capped the "T" as you see here (left center below the PCV valve).



I also installed the fresh air duct hose between the grill side port my heater inlet. It took over an hour. There is barely enough room for the flex tube to make the 90 degree turn between the inner fender wall and the grill side wall. Since the flexible tube fits snuggly over the flanged tube attachment projection on the grill side wall, the tube must approach it squarely to slip over the edge. With it all bunched into the tight corner it is extremely difficult to square it up. On top of that, all the front light wiring attaches to the fender mounted terminal which, naturally, is completely in the way when trying to reach into that corner.

I fought with it for about 45 minutes until I decided throw in the towel.

Plan "B"...I decided to pull the attachment flange off the side of the grill, and remove the wiring terminal and horn relay from the fender. I attached the flex hose to the loose attachment flange with a band clamp and fed it into the space, and bolted it back on, reattached the terminal and horn relay and called it "finished" in about 15 minutes.

The green painters tape is holding a seal I attached over the coolant hose penetrations into my heater box. I may have to rethink the way I finish that, given the proximity to the exhaust manifold.

I reassembled the speedometer cluster assembly, so that's ready to go in. The new oil pump is ready to go in when Joe gets home.

The PO jury rigged a cover over the fuel tank opening for his (wrong resistance values) float level sender attachment. We have to figure that out for our new level sensor. He used a electrical "J box" cover which actually wasn't a bad idea, but it looks a bit kludgey. It is forever hidden under the front seat and it works, but while we are at it maybe we can finish it off a bit better if we can come up with a better idea... if not, "J box" cover it will remain.

And we had a lot of fuel spilling into the carb throat when the engine turned off... 'got to look at that.

Otherwise... we are getting awfully close !!!

'Sure am glad Joe is back on Monday!

 

I'm looking a few days ahead to carburetor work.



Please ignore the paint cap, it is keeping trash out of the throat.

I interpret this to be Solex carburetor. Today's internet search suggests two or three principal reasons for continued fuel flow when the engine shuts off:
(1) excess fuel pressure (> 2 psig)
(2) improper float position (i.e. needing adjustment)
(3) fouled needle valve (leaking)

I just ordered a 1-4 psi Holley fuel pressure regulator ($32.00, Ebay); I'll have it next Monday.

We'll review the FSM and earlycj5.com (and others) for existing advice for checking the float and valve seat. But since I don't have a carb rebuild kit (gaskets) I'm going to try the pressure regulator first.