Speedometer issues. Need Help.
02-13-2019, 06:09 AM
#22
At this point, we don't know if the problem lies in the car's modules/sensors or in the actual cluster. You could go spend several hundred dollars to program and certify a new cluster or re-build the one you have only to install it and have the same problem.
Using a live scanner will tell you what the car is reading for speed, which you can compare to the scanner to reliably isolate the problem. The scanner (if you buy it) is also an investment that you will continually use. (It isn't throw-away.)
02-13-2019, 12:31 PM
#23
TECH Resident
02-13-2019, 12:41 PM
#24
TECH Resident
Easiest solution is to just grab another cluster from a junkyard and slap it in. If the problem is still there return the cluster or sell it. If the problem isn't in the cluster then it's either in the programming or the gear ratio in the car was probably changed.
02-13-2019, 10:18 PM
#25
02-14-2019, 06:50 AM
#26
GM doesn't tell us what is on the chips, but I recall seeing information (on another site) eons ago, showing that the VIN was encoded in the cluster like it is on the newer ones. (Presumably this is done for tamper tracking.)
The OP should consult local state laws before doing a swap to make sure no special certifications need to be filed. The GM Service Manual directs that the Odometer must be zeroed out or set to the same mileage as the old one. I don't know where this direction comes from, but I presume it covers the bases/requirements for all the US States and Canada and that doing a straight swap is problematic for some State. (somewhere)
The thread above lands on direction similar to the Service Manual, but it doesn't provide insight as to if the clusters are matched to the car through the Tech2 programming process. This would be interesting to know, if the VIN is indeed there in the EEPROM coding, if the Tech2 allows the user to see it, or if the Tech2 allows the user to re-program it with the mileage.
Last edited by wssix99; 02-14-2019 at 06:57 AM.
02-14-2019, 07:16 AM
#27
The plot thickens... I just looked up the instrument panel cluster replacement procedure in the factory service manual. The good news - for the 1998 model that the OP has, it's just a simple physical replacement (remove the old and install the new). For 1999-2002 models an extra step of synchronizing the instrument panel to the SIR (airbag) system is required. They give detailed instructions on how to do this with the scan tool. There is no mention of VIN matching - just this synchronization - but who knows what is going on in the background during that process.
02-14-2019, 09:50 AM
#28
I swapped them already , they worked fine without doing anything. Everything worked. I also know for a fact you can just swap the old mileage display into the new cluster and the mileage will follow the display. So its safe to ASSUME THE MILEAGE IS STORED IN THE MILEAGE DISPLAY. I'd buy the cheapest cluster you can find and just use it to test ................
02-14-2019, 10:44 AM
#29
For 1999-2002 models an extra step of synchronizing the instrument panel to the SIR (airbag) system is required. They give detailed instructions on how to do this with the scan tool. There is no mention of VIN matching - just this synchronization - but who knows what is going on in the background during that process.
02-14-2019, 11:23 AM
#30
TECH Resident
I'm convinced this is how the engineers work at GM. "The boss wants to know what we did this month. Just tell him we optimized the digital integration of the driver readout interface. What's that mean? I spliced the ground from the oil pressure gauge into the airbag warning light"
02-15-2019, 06:53 AM
#31
I'm convinced this is how the engineers work at GM. "The boss wants to know what we did this month. Just tell him we optimized the digital integration of the driver readout interface. What's that mean? I spliced the ground from the oil pressure gauge into the airbag warning light"
As the years go by, we have to stretch ourselves more and more to think about "the way it was" when these cars are designed. Even for the late models, a lot of the electronics and features were carry-over from the Third Gen and designed to the state-of-the-art in 1979. In the case of the gauge cluster, I expect that was a new design for the fourth gen, but was on the engineer's drafting table (they still used pencils and paper back then) in 1989. Windows was still a new thing and electronics weren't very advanced:
Turning back odometers has always been a big issue for the industry, but in the early 90's, spoofing air bag systems and installing faulty/bad/scam airbags was a new "bad thing." I suspect this is what someone was trying to stop. At the time, air bags were just becoming mandated and were outrageously expensive. Having air bags go off in a crash was often a certain way to get a car totaled because they added so much to the cost of a repair.
02-15-2019, 10:59 AM
#32
TECH Resident
Spend a decade in the b-body world and you'll quickly realize the engineers weren't all that great.
The bubble body was too long for the old chassis so the rear axle is pushed to the front of the wheel well. The fix is longer rear control arms.
The rear windows don't go down all the way because the wheel well (that was too far back for the chassis) is too far forward on the door.
The transmission is too weak to handle the power and weight of the car (similar issue to the weak rear in the f-body)
The power steering will literally boil when driven hard.
The opti was a bad idea and then the problem was compounded by putting it in a horrible place.
The water pump has a weep hole directly over the opti just to make sure that the opti dies.
The digidash alternates between 8, h, H, 9, 6 or strobes or just dies. The short fix is to clean and bend the spring tabs. Eventually you just end up punching the cluster when it stops working.
Another issue is that high electric load situations like driving with the lights and wipers on overheats the aux fuse post and it literally melts. The only fix is to gut the fuse block and replace the post with the updated version from the tsb.
The last screw up is using the wrong gauge wiring for the fuel pump. Over time the thin wiring burns up inside the gas tank, which is a potentially fatal problem, that luckily for most just ends up being a major inconvenience.
The bubble body was too long for the old chassis so the rear axle is pushed to the front of the wheel well. The fix is longer rear control arms.
The rear windows don't go down all the way because the wheel well (that was too far back for the chassis) is too far forward on the door.
The transmission is too weak to handle the power and weight of the car (similar issue to the weak rear in the f-body)
The power steering will literally boil when driven hard.
The opti was a bad idea and then the problem was compounded by putting it in a horrible place.
The water pump has a weep hole directly over the opti just to make sure that the opti dies.
The digidash alternates between 8, h, H, 9, 6 or strobes or just dies. The short fix is to clean and bend the spring tabs. Eventually you just end up punching the cluster when it stops working.
Another issue is that high electric load situations like driving with the lights and wipers on overheats the aux fuse post and it literally melts. The only fix is to gut the fuse block and replace the post with the updated version from the tsb.
The last screw up is using the wrong gauge wiring for the fuel pump. Over time the thin wiring burns up inside the gas tank, which is a potentially fatal problem, that luckily for most just ends up being a major inconvenience.
02-23-2019, 11:36 AM
#33
Teching In
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UPDATE:
After some long hours of testing, i figured out it was a cracked Speedometer head, usually when the speedometer is doubling its usually a cracked head. anyways i replaced the Speedo, and it works quite fine now. it gives me the correct speed, and she is shifting like new! thank you all who helped me to figure this out.
until next time -Ant
After some long hours of testing, i figured out it was a cracked Speedometer head, usually when the speedometer is doubling its usually a cracked head. anyways i replaced the Speedo, and it works quite fine now. it gives me the correct speed, and she is shifting like new! thank you all who helped me to figure this out.
until next time -Ant
07-31-2019, 08:14 AM
#34
I recently bought a 2000 Firebird Trans AM WS6 and i have the same problem. My tires are as they should be and my speedometer is registering steadly. I use my Iphone to get the proper speed and when I'm showing 118KPH on my phone GPS the car shows 100KPH...So I have to drive 118 to get the proper speed of 100. There is only three things that could cause this and that is the VSS, Wrong size tires, or Differintial gear Ratio gears. I know its not the VSS or the Tires so someone changed my diff gears and didn't tell me about. I'm told that you can get a caliberation done on the speedometer to cure the problem and here in Newfoundland where I live the dealer dosent know how to do it.... Terra Nova Motors in St.John's, NL (Idiots) . I'm going to check the gear ratio myself by measuring the rotation of the driveshaft with the rear wheels and if you go to Amazon.ca you can buy a speedometer caliberation tool...The part number is Hypertech 732500. The cost is about $230 , so I'm seriously thinking of ordering one and programing the speedometer myself....Let me know how you make out with it.....
07-31-2019, 09:09 AM
#35
Speedometer Caliberation Programmer Does anyone use a caliberation tool to caliberate there speedometer on a GM vehicle. I have a 2000 Trans AM WS6 with speedodometer issues. I am thinking of buying one from Amazon (Hypertech 732500) I'm hoping that it is the right one . I also have Boue Driver which reads out on my Iphone but not sure if that will actually caliberate the speedometer.......Comments Please????:
08-01-2019, 10:55 PM
#36
So I have to drive 118 to get the proper speed of 100. There is only three things that could cause this and that is the VSS, Wrong size tires, or Differintial gear Ratio gears. I know its not the VSS or the Tires so someone changed my diff gears and didn't tell me about.
08-02-2019, 01:30 PM
#37
It changes with speed, when I'm doing 60 on my GPS the speedometer shows 53 . I'm always showing faster on my speedometer than the GPS shows me. Its a smooth transition , the needle is steady and smooth but just shows me a different reading for every speed.....