98' speedometer question. - Lone Star Stangs

Sven · 06-30-2009, 06:07 PM

My speedometer only works intermittently... sometimes it reads correct, sometimes not at all, and sometimes it wraps around and pegs against the pin as-if Im going 200mph.

When I bought the car it had 3.73s and the speedo read correct.
I later switched to 4.10s and added a speed-cal, but had to mess with the dip switches to get it to calibrate correctly... (purchased used)

It seemed to work well, but lately I've been getting a check engine light and (after replacing several sensors and tracking a vacuum leak) the guy working on it says its now showing a speedometer-related code (cant remember his exact term for it), but he thinks the speed-cal is bad.

Im not sure what to do at this point... Regardless of wether the speedo is working correctly, the odometer works. Should I just take the s-c out alltogether and get a new one? Is there a replacement gear or would I need a tuner to recalibrate the speedo without the s-c. Are the '98 speedos gear-driven or electronic?

2k4mk1 · 07-01-2009, 06:44 AM

Elevtronic however there is a gear that drives teh signal unit. It sounds like your gear is bad or the sending unit is bad.
Pull the unit off and ck the teeth on the gear. I cant recall but I beleive the gears are different colors for different sizes (ratios) get the same color you have if yours is bad.

Not familiar with speed cal so I guess that could be an issue as well. Try removing it and see if it at least works consistantly.

Sven · 07-02-2009, 08:14 PM

So if I order one of these I should be able to do-away with the speed-cal?
Speedometer Recalibration Gears - '79-'98 Ford Mustang

2k4mk1 · 07-03-2009, 08:30 AM

I do believe that will work.
Just need to be sure you get the proper one for your rear gear ratio.

Sven · 07-03-2009, 06:19 PM

For my current 4.10 ratio, it looks like the difference is if its a 7-tooth or an 8-tooth.

BlackSunshine01 · 07-06-2009, 01:31 AM

ever get it figured out?

Sven · 07-06-2009, 08:20 AM

Getting it back from the shop today - Im going to work on the speedo issue this week.

Sven · 07-12-2009, 10:38 PM

Shop installed a new sending unit.

I purchased the new calibration gear from the Steeda website Wednesday, it arrived Saturday. 15min install, seems to be working fine. problem resolved.

06-30-2009, 06:07 PM	#1
Sven '98GT-4.10s-Flows Join Date: Jan 2006 Location: SATX Posts: 350 iTrader: (3) Real Name: Ron	98' speedometer question. My speedometer only works intermittently... sometimes it reads correct, sometimes not at all, and sometimes it wraps around and pegs against the pin as-if Im going 200mph. When I bought the car it had 3.73s and the speedo read correct. I later switched to 4.10s and added a speed-cal, but had to mess with the dip switches to get it to calibrate correctly... (purchased used) It seemed to work well, but lately I've been getting a check engine light and (after replacing several sensors and tracking a vacuum leak) the guy working on it says its now showing a speedometer-related code (cant remember his exact term for it), but he thinks the speed-cal is bad. Im not sure what to do at this point... Regardless of wether the speedo is working correctly, the odometer works. Should I just take the s-c out alltogether and get a new one? Is there a replacement gear or would I need a tuner to recalibrate the speedo without the s-c. Are the '98 speedos gear-driven or electronic?

07-01-2009, 06:44 AM	#2
2k4mk1 WHERE'S MY CHECK AT FOOL?????!!!!!!!! Join Date: Dec 2003 Location: SanAntonio Posts: 8,316 iTrader: (4) Real Name: Don	Elevtronic however there is a gear that drives teh signal unit. It sounds like your gear is bad or the sending unit is bad. Pull the unit off and ck the teeth on the gear. I cant recall but I beleive the gears are different colors for different sizes (ratios) get the same color you have if yours is bad. Not familiar with speed cal so I guess that could be an issue as well. Try removing it and see if it at least works consistantly. __________________ 04 Oxford White MACH1,5 SPD with IUP,K&NAircharger Borla Stingers,SLP Catted X pipe,Tri-ax,SCT Flashtune,Max Mtr Spt 4 bolt adj C/C plates, Drilled/Slotted rotors all 4 corners. 17x9 frt 17x10 rear D/D Blk bullitt's 281 rwhp on Mustang Dyno,306 rwhp on a Dynojet 94 Black Lightning Daily Driver&85GT FACH1 Project under construction

07-06-2009, 01:31 AM	#6
BlackSunshine01 BRING ME MY RAPE SHOES! Join Date: Jan 2008 Location: north east s.a. Posts: 1,230 iTrader: (0)	ever get it figured out? __________________ getting there2"drop,borla stingers,sct x-cal

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07-02-2009, 08:14 PM	#3
Sven '98GT-4.10s-Flows Join Date: Jan 2006 Location: SATX Posts: 350 iTrader: (3) Real Name: Ron	So if I order one of these I should be able to do-away with the speed-cal? Speedometer Recalibration Gears - '79-'98 Ford Mustang

07-03-2009, 08:30 AM	#4
2k4mk1 WHERE'S MY CHECK AT FOOL?????!!!!!!!! Join Date: Dec 2003 Location: SanAntonio Posts: 8,316 iTrader: (4) Real Name: Don	I do believe that will work. Just need to be sure you get the proper one for your rear gear ratio.

07-03-2009, 06:19 PM	#5
Sven '98GT-4.10s-Flows Join Date: Jan 2006 Location: SATX Posts: 350 iTrader: (3) Real Name: Ron	For my current 4.10 ratio, it looks like the difference is if its a 7-tooth or an 8-tooth.

07-06-2009, 08:20 AM	#7
Sven '98GT-4.10s-Flows Join Date: Jan 2006 Location: SATX Posts: 350 iTrader: (3) Real Name: Ron	Getting it back from the shop today - Im going to work on the speedo issue this week.

07-12-2009, 10:38 PM	#8
Sven '98GT-4.10s-Flows Join Date: Jan 2006 Location: SATX Posts: 350 iTrader: (3) Real Name: Ron	Shop installed a new sending unit. I purchased the new calibration gear from the Steeda website Wednesday, it arrived Saturday. 15min install, seems to be working fine. problem resolved.