Problematic Questions

Rosco · 03-17-2002, 11:09 AM

I was wondering, actually I have a couple questions. First off, my speedometer is off about 5 mph high, It's not really a problem, but the real problem is that my speedo likes to skip, alot. After I hit about 30 mph the thing just starts jumping like crazy until i hit around 60. While it's at like...58-59 though it'll stay at 60 and kinda jump around 3-4 mph either way. I'm not really sure how the cable works and all so I have no idea what to start with. Also another thing is, my gas gauge. With like 1/4 tank left it'll just drop down to empty. The gas tank was replaced before and the fuel pump as well.

Unit 5302 · 03-17-2002, 03:05 PM

The speedometer cable is a thin, wirelike cable that runs through an external housing. When the housing rusts, or gets debris inside, or the cable itself is damaged, it can wind up a little. What that does is increase the stress and make the cable constantly play catch up and slow down as the turning pressure on it is not constant. Kind of like a teeter totter.

Replacement of the cable is required. A lot of times both internal and external housings must be replaced.

Your fuel gauge sending unit is burned out. Count yourself lucky that it's failing at 1/4 tank and not like most people's at full tank. Mine stays at full tank until I have less than a 1/4 of a tank left and then it drops. I checked several parts stores and all of them had discontinued the part that I need. The fuel level sending unit is a seperate unit on 87-88 cars anyway, located in the fuel tank next to the fuel pump itself.

Somebody gave me a part number a while back, but I'm gonna wait until spring and warm weather before I undertake working on mine.

FMS-M10871A962 I think that is the part number.

Rosco · 03-17-2002, 11:31 PM

Alright, now, do you know where that fuel gauge sending unit is located on my '91? I would assume it would be the same for the '89-93 cars, but I have no real idea.

Also, for my speedo cable, do you know how much something like that would cost to fix? and would i be able to do it myself or should I leave it up to a real mechanic?

Unit 5302 · 03-18-2002, 01:43 AM

I would assume it's in the same location.

The speedo cable is a very easy, but a little time consuming process. You have to take the instrament cluster off.

zepherman · 03-18-2002, 01:50 AM

The speedo cable isnt really all that hard, but its kind of a pain in the *****. If you have the time and want to save some money you could do it yourself. The speedo plugs into the back of your gauge cluster so you have to remove the part of the dash around the gauge cluster to get to it. the cable runs from the back of the gauge cluster, through the firewall, through the engine compartment, under the car, to the transmission. when you disconnect the cable from the gauge cluster you can pull it through the firewall. disconnect it from the speed sensor, under the car, which is on the drivers side of the transmission and then remove it from the car. My speedo cable is grey. yours is probably the same. Remeber to note the way that the cable is run and install the new cable the same way. when you install the new one make shure that it doesnt run to close to the exhaust or the heat will melt it. Good luck

zepherman · 03-18-2002, 01:56 AM

BTW, disconnect the cable from the speed sensor first so that you will have some slack when you go to disconnect it from the gauge cluster. otherwise its hard to pull he cluster out to disconnect te cable. Or at least thats how i remember it

Rosco · 03-18-2002, 02:28 AM

Heh, yeah I've already taken apart the whole front dash. Including the cluster to see if anything was melted during something else (stupid kid that owned it before me had the fog lamps rigged to the running lamps). So basically, the cable will run from the back of cluster, through the firewall, to the tranny? It's as simple as that? Well at least how it runs? Oh yeah, If i get 3.55 gears what would I hafto change in the cable so my speedo wouldn't be off? Also, do you know where I could pick up a new cable?

zepherman · 03-18-2002, 02:52 AM

if you change gears you need to get the speedo gear that matches yor rear gear ratio. The speedo plugs into the speed sensor, the speed sensor plugs into the tranny, on the end of the speed sensor is the speedo gear which is held on by a little clip. all you have to do is pull the speed sensor and switch the little plastic speedo gear. Whoever does your gears should be able to get you a speedo gear and will probably install it for you as partof the gear swap. you should be able to get a speedo cable from a local parts store. when you get the new cable be sure you are getting the metal cable itself and the housing that it goes in which is a long flexable tube. I refer to both of these together as "the cable"

Rosco · 03-18-2002, 08:02 AM

Alright thanks alot, So i'm getting both the "cable" itself and the housing. Alright, I'm no super mechanic, and actually I haven't ever torn my car apart a 'whole' lot. You think this cable is gonna be hard for me to change? Oh you know the where about's of where it plugs into the tranny? heh, Maybe I should check my shop manual. Yeah, I'll take a look at that and see what that says about it.

03-17-2002, 11:09 AM	#1
Rosco Registered Member Join Date: Mar 2002 Location: Vestal, NY Posts: 307	Problematic Questions I was wondering, actually I have a couple questions. First off, my speedometer is off about 5 mph high, It's not really a problem, but the real problem is that my speedo likes to skip, alot. After I hit about 30 mph the thing just starts jumping like crazy until i hit around 60. While it's at like...58-59 though it'll stay at 60 and kinda jump around 3-4 mph either way. I'm not really sure how the cable works and all so I have no idea what to start with. Also another thing is, my gas gauge. With like 1/4 tank left it'll just drop down to empty. The gas tank was replaced before and the fuel pump as well. __________________ 1989 Mustang 5.0 Conversion, Full Saleen ground effects and spoiler, '94 saleen decal set, '93 Saleen Seats, Black interior from a '93, Steeda quadrant, smog pump delete, a/c delete, Steeda Tri-Ax shifter, '97 rear differential, aluminum driveshaft, 5 lug conversion, '97 rear disc brakes, southside upper and lower control arms, '99 GT Anniversary wheels, flowtech longtubes, flowtech offroad H-pipe, saleen lowering springs, kyb shocks, caster/camber plates

03-17-2002, 11:31 PM	#3
Rosco Registered Member Join Date: Mar 2002 Location: Vestal, NY Posts: 307	Alright, now, do you know where that fuel gauge sending unit is located on my '91? I would assume it would be the same for the '89-93 cars, but I have no real idea. Also, for my speedo cable, do you know how much something like that would cost to fix? and would i be able to do it myself or should I leave it up to a real mechanic? __________________ 1989 Mustang 5.0 Conversion, Full Saleen ground effects and spoiler, '94 saleen decal set, '93 Saleen Seats, Black interior from a '93, Steeda quadrant, smog pump delete, a/c delete, Steeda Tri-Ax shifter, '97 rear differential, aluminum driveshaft, 5 lug conversion, '97 rear disc brakes, southside upper and lower control arms, '99 GT Anniversary wheels, flowtech longtubes, flowtech offroad H-pipe, saleen lowering springs, kyb shocks, caster/camber plates

03-18-2002, 01:50 AM	#5
zepherman Registered Member Join Date: May 2001 Location: Oklahoma City OK USA Posts: 236	The speedo cable isnt really all that hard, but its kind of a pain in the *****. If you have the time and want to save some money you could do it yourself. The speedo plugs into the back of your gauge cluster so you have to remove the part of the dash around the gauge cluster to get to it. the cable runs from the back of the gauge cluster, through the firewall, through the engine compartment, under the car, to the transmission. when you disconnect the cable from the gauge cluster you can pull it through the firewall. disconnect it from the speed sensor, under the car, which is on the drivers side of the transmission and then remove it from the car. My speedo cable is grey. yours is probably the same. Remeber to note the way that the cable is run and install the new cable the same way. when you install the new one make shure that it doesnt run to close to the exhaust or the heat will melt it. Good luck __________________ 90 GT 25th Anni. Did the AOD to T-5 swap, SPEC clutch, Steeda Tri-Ax shifter, BBK 2½ inch off-road H pipe, Flows, BBK 70mm TB/EGR, Ford Racing aluminim driveshaft, 3.55's, welded subframes, Ram Air, 3 core radiator, NOS dry kit 75 shot, and a K&N filter. 12.9 @ 108

03-18-2002, 01:56 AM	#6
zepherman Registered Member Join Date: May 2001 Location: Oklahoma City OK USA Posts: 236	BTW, disconnect the cable from the speed sensor first so that you will have some slack when you go to disconnect it from the gauge cluster. otherwise its hard to pull he cluster out to disconnect te cable. Or at least thats how i remember it __________________ 90 GT 25th Anni. Did the AOD to T-5 swap, SPEC clutch, Steeda Tri-Ax shifter, BBK 2½ inch off-road H pipe, Flows, BBK 70mm TB/EGR, Ford Racing aluminim driveshaft, 3.55's, welded subframes, Ram Air, 3 core radiator, NOS dry kit 75 shot, and a K&N filter. 12.9 @ 108

03-18-2002, 02:28 AM	#7
Rosco Registered Member Join Date: Mar 2002 Location: Vestal, NY Posts: 307	Heh, yeah I've already taken apart the whole front dash. Including the cluster to see if anything was melted during something else (stupid kid that owned it before me had the fog lamps rigged to the running lamps). So basically, the cable will run from the back of cluster, through the firewall, to the tranny? It's as simple as that? Well at least how it runs? Oh yeah, If i get 3.55 gears what would I hafto change in the cable so my speedo wouldn't be off? Also, do you know where I could pick up a new cable? __________________ 1989 Mustang 5.0 Conversion, Full Saleen ground effects and spoiler, '94 saleen decal set, '93 Saleen Seats, Black interior from a '93, Steeda quadrant, smog pump delete, a/c delete, Steeda Tri-Ax shifter, '97 rear differential, aluminum driveshaft, 5 lug conversion, '97 rear disc brakes, southside upper and lower control arms, '99 GT Anniversary wheels, flowtech longtubes, flowtech offroad H-pipe, saleen lowering springs, kyb shocks, caster/camber plates

03-17-2002, 03:05 PM	#2
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	The speedometer cable is a thin, wirelike cable that runs through an external housing. When the housing rusts, or gets debris inside, or the cable itself is damaged, it can wind up a little. What that does is increase the stress and make the cable constantly play catch up and slow down as the turning pressure on it is not constant. Kind of like a teeter totter. Replacement of the cable is required. A lot of times both internal and external housings must be replaced. Your fuel gauge sending unit is burned out. Count yourself lucky that it's failing at 1/4 tank and not like most people's at full tank. Mine stays at full tank until I have less than a 1/4 of a tank left and then it drops. I checked several parts stores and all of them had discontinued the part that I need. The fuel level sending unit is a seperate unit on 87-88 cars anyway, located in the fuel tank next to the fuel pump itself. Somebody gave me a part number a while back, but I'm gonna wait until spring and warm weather before I undertake working on mine. FMS-M10871A962 I think that is the part number.

03-18-2002, 01:43 AM	#4
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	I would assume it's in the same location. The speedo cable is a very easy, but a little time consuming process. You have to take the instrament cluster off.

03-18-2002, 02:52 AM	#8
zepherman Registered Member Join Date: May 2001 Location: Oklahoma City OK USA Posts: 236	if you change gears you need to get the speedo gear that matches yor rear gear ratio. The speedo plugs into the speed sensor, the speed sensor plugs into the tranny, on the end of the speed sensor is the speedo gear which is held on by a little clip. all you have to do is pull the speed sensor and switch the little plastic speedo gear. Whoever does your gears should be able to get you a speedo gear and will probably install it for you as partof the gear swap. you should be able to get a speedo cable from a local parts store. when you get the new cable be sure you are getting the metal cable itself and the housing that it goes in which is a long flexable tube. I refer to both of these together as "the cable" __________________ 90 GT 25th Anni. Did the AOD to T-5 swap, SPEC clutch, Steeda Tri-Ax shifter, BBK 2½ inch off-road H pipe, Flows, BBK 70mm TB/EGR, Ford Racing aluminim driveshaft, 3.55's, welded subframes, Ram Air, 3 core radiator, NOS dry kit 75 shot, and a K&N filter. 12.9 @ 108

03-18-2002, 08:02 AM	#9
Rosco Registered Member Join Date: Mar 2002 Location: Vestal, NY Posts: 307	Alright thanks alot, So i'm getting both the "cable" itself and the housing. Alright, I'm no super mechanic, and actually I haven't ever torn my car apart a 'whole' lot. You think this cable is gonna be hard for me to change? Oh you know the where about's of where it plugs into the tranny? heh, Maybe I should check my shop manual. Yeah, I'll take a look at that and see what that says about it. __________________ 1989 Mustang 5.0 Conversion, Full Saleen ground effects and spoiler, '94 saleen decal set, '93 Saleen Seats, Black interior from a '93, Steeda quadrant, smog pump delete, a/c delete, Steeda Tri-Ax shifter, '97 rear differential, aluminum driveshaft, 5 lug conversion, '97 rear disc brakes, southside upper and lower control arms, '99 GT Anniversary wheels, flowtech longtubes, flowtech offroad H-pipe, saleen lowering springs, kyb shocks, caster/camber plates

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