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Creighton
02-26-2017, 01:40 AM
A near mint 141k cluster has both needles at near 12:00 o'clock.
Cluster showing 89k doubt that, is resting at 11:00.
My working 122k has the needles at 1:00. Low fuel light comes on when gauge shows 1/4 tank.

Any way to test what is correct?
Bench set up to work on gauge clusters :-)
Thanks.
Creighton

KMT
02-26-2017, 02:54 AM
Since the boost gauge is mechanical, a basic vacuum/pressure hand-pump w/gauge should help check/calibrate it. I've had some sit wonky and heard they act out if they get moisture/rust/gunk inside - old age doesn't help. Best to simply replace at that point...maybe donate it to target practice ;)

I'd be more concerned how it reads in operation than where it sits when off. Might re-center the needle so it sits @ 12:00, only to find it's faking a reading when the engine is running. The SC's gauges aren't Rolex grade, so don't put too much trust in it :)

Fuel gauge is electric, of course, and as I recall, they don't zero when off.

I'd find a known good one first, to confirm that either the sender or the anti-slosh board on the cluster aren't root cause (be aware those daughter boards may look similar, but vary by year and need to match the cluster). The sender could be rusted and/or wiring at the connection (pump and sender are one unit) could be damaged, corroded, melted - may have hurt the gauge?. Does it read correct when full? How many gallons did it take when the gauge said 1/2? Might want to confirm no damage to the tank floor. Be sure no one tried to lift the car by it at some point in the past. Bench testing a fuel gauge might be covered in the factory manual, but you'd need a way to supply a calibrated load/resistance, including grounds to even get close, I think. If you can get your hands on a new pump/sender, you might be able to use the EVTM to help mock up a reliable jig on the bench... Just keep in mind it's very easy to wreck it when testing, so...

Is this the same car w/the questionable wiring in the engine bay? If that mess is any indication, there's no telling what's been done to the cluster - good luck.

fstcoup
02-26-2017, 07:14 AM
I never run my cars past 1/8 on the fuel gauge, at that point they're empty . The gauges on these cars are not really accurate and all seem to vary somewhat as to what the real reading is.

potshotscott
02-26-2017, 05:12 PM
Dude's got all the cool stuff in his photo... Test equipment, multimeters, a pistol and what might be a power supply. Love it!

RalphP
02-26-2017, 09:03 PM
A few additions I'd recommend are:

a) A frequency generator; you can fake a 60MPH signal with a 133.3 Hz signal (and other speeds with the proper signals!); square wave, 5V to 12V, about 50% duty works fine.

That also helps to calibrate one safely *grins*

(8,000 pulses per mile, divide by how many seconds you want to traverse that mile in, and that's the frequency; almost any frequency can be used to spot check other speeds, up to about 300Hz or so depending on the speedo.)

b) Some dummy load resistors; the later EVTMs (and quite possibly the ones for the SC, don't know, haven't looked yet) show what value should be "FULL" and "EMPTY" on a fuel gauge, what should be "COLD" and "HOT" on a temp gauge, etc.

Otherwise, I fully approve *grins*

(I'd need a speed controlled motor with a flex shaft and a speedo needle for my Dakota; otherwise, all the same stuff works on it.)

RwP

Creighton
02-26-2017, 09:29 PM
Not much in either manual. Agree moving needles not a good plan. All gauges work on the 89. No sign of mickey mouse work other than DIS harness. Plan is clean up the unit with 12:00 F/B and put the 145 on it. Replace all bulbs and just swap out the one in the car. Sort no workies later. Happy the needle came of with no drama on the 145. Reset ODO up next. Don't see any common parts between the 120 and 145.

Yep, Dual DC Power Supply. Darn handy thing to have. The 20' basement pellet gun "range" is a good threat for misbehaving bits and stress relief :-).

Thanks all,
Creighton

KMT
02-26-2017, 09:48 PM
BTW, unless you know it's been done, I'd suggest replacing the small gear set in the 145 speedo head that quite commonly fails due to age so you don't have to go back in soon.

Creighton
02-26-2017, 10:21 PM
RwP, A and B on the list. C is a scope haven't needed one in 55 yrs but just want one :-).
KMT, Plan on it. Just need to sort what kit to get.
Creighton

KMT
02-26-2017, 11:24 PM
Just need to sort what kit to get.

See https://www.supercoupeperformance.com/odometer-repair-kit-493

Price has gone up a tad since I did mine in 2013.

RalphP
02-26-2017, 11:38 PM
RwP, A and B on the list. C is a scope haven't needed one in 55 yrs but just want one :-).
KMT, Plan on it. Just need to sort what kit to get.
Creighton

Heh.

There's some decent inexpensive DSO kits out now for if you don't want or need much; I built one, then found a list of voltage vis speed for the VSS sensor so didn't need to worry about it (and scope traces of the waveform).

As to kit - there's one supplier in Blanchard LA that seems to be the least expensive in the USA; http://www.laspeedometergear.com/Odometer%20gear%20Ford%20Dodge.htm .

RwP

potshotscott
02-27-2017, 12:28 AM
I've had great luck with this gear from Hungary. Don't know if he prints them on a 3D printer or if they're legit but 10000 miles later on my LX and all is well.

http://www.ebay.com/itm/20-tooth-odometer-gear-speedometer-cog-for-Volvo-Porsche-Chrysler-Ford-etc-/271645832525?hash=item3f3f5a754d:g:zp4AAOSweW5VeYN L&vxp=mtr

Creighton
02-27-2017, 03:19 AM
Great links! Thanks.

So with 145 speedo awaiting parts. Poked about with the two clusters. The green one is F0SF-10C956-A. Blue is the 12:00 E9SF-10C956-C. Tore the A down to see what kinda room is in the housing. All screws are same length but self-threading so less chance of breaking the posts if put back in same hole. I only see one minor diff. between the A and C. So far...

Good progress restoring the lens on the C with Novus #1. Fun times.
Creighton

Creighton
03-01-2017, 01:38 AM
Got a laugh. All 18 bulbs/sockets tested good on the 89 141k cluster. Wish the spendy bits would hold up as well :-)
Creighton