SPEEDO

I don't know if this has been covered becuase I haven't found anything about it. OK, MY speedometer does not read anything above 55MPH:sad: .. Has ANYONE had this similar problem and, any possible solutions would be GREATLY appreciated!

The instrument cluster used to be mechanical gadgets and analog gauges. Now (at least for speedo and odo) it is a device calculating speeds and mileage based on VSS input coming through the PCM.

You MIGHT have a problem with the wiring, or the VSS that is outside the transmission. How to tell: are your shift points wack? If so, most likely VSS possibly with wiring issues. If not, likely is wiring or gauge. RockAuto, they are closing out Delphi sensors for less than $10 each.

Time for you to find/buy a factory (NOT third-party like Chilton or Haynes or even Alldata) service manual... and do some old-school troubleshooting. There's no inherent frequent flaw here.

Maybe need to increase your supercharger boost! (Sorry, I needed a laugh)

First thing I'd try is to have the car scanned through the OBD plug on a drive (assuming you have a 96 or later car. There's no description in your sig, and you didn't mention the year). A scan tool can read MPH and that will tell if the gauge is broken, or if the PCM actually thinks the speed is low, indicating a bad speed sensor. If the scan tool reads higher speeds, the problem is in the gauge cluster. Hope this helps, and good luck.

albertj wrote:

The instrument cluster used to be mechanical gadgets and analog gauges.  Now (at least for speedo and odo) it is a device calculating speeds and mileage based on VSS input coming through the PCM.

You MIGHT have a problem with the wiring, or the VSS that is outside the transmission.  How to tell: are your shift points wack? If so, most likely VSS possibly with wiring issues.   If not, likely is wiring or gauge.   RockAuto, they are closing out Delphi sensors for less than $10 each.  

Time for you to find/buy a factory (NOT third-party like Chilton or Haynes or even Alldata) service manual...  and do some old-school troubleshooting.  There's no inherent frequent flaw here.

Thanks a lot for the thorough input! Now that you mention it my shift points have been out of wack for awhile now, I was just thinking it was the TC was showing its age..Would that be the GIANT plug hanging out of the side? I do need too find me a manual as I plan on doing the majority of my work like I've been doing(just been reading on this site using the very informative info)because things are needing too be changed.

AA wrote:

Maybe need to increase your supercharger boost! (Sorry, I needed a laugh)

First thing I'd try is to have the car scanned through the OBD plug on a drive (assuming you have a 96 or later car. There's no description in your sig, and you didn't mention the year). A scan tool can read MPH and that will tell if the gauge is broken, or if the PCM actually thinks the speed is low, indicating a bad speed sensor. If the scan tool reads higher speeds, the problem is in the gauge cluster. Hope this helps, and good luck.

LOL. I would LOVE to increase BOOST I was want too take care of these other issues before I really mod. Would a shop usually be willing to do that? I don't have my own scan tool. I'll have to add that too the list...

Depends on the shop. Something so simple like that, they might do it for free. It would only take 5 mins to plug in and read the speed while driving.

AA wrote:

Depends on the shop. Something so simple like that, they might do it for free. It would only take 5 mins to plug in and read the speed while driving.

Come to think of it you could get a scan dongle off eBay and download scanner software. If you don't have a scanner to read codes etc., might be time to get one.

You can get one for wifi, bluetoothor wired.   They either come with software or instruction s on how to get it for free/cheap.  The $$ software is a bit more capable but not as good as a genuine Tech II.

AA wrote:

Depends on the shop. Something so simple like that, they might do it for free. It would only take 5 mins to plug in and read the speed while driving.

I will have to look more into the shops here. I don't have any shops as, I don't really have trust in most mechanics.

9ty7rivi wrote:

AA wrote:

Depends on the shop. Something so simple like that, they might do it for free. It would only take 5 mins to plug in and read the speed while driving.

I will have to look more into the shops here. I don't have any shops as, I don't really have trust in most mechanics.

you might wanna try these guys on the south side of San Antonio: https://www.spitfireautoelectric.com/

albertj wrote:

9ty7rivi wrote:

AA wrote:

Depends on the shop. Something so simple like that, they might do it for free. It would only take 5 mins to plug in and read the speed while driving.

I will have to look more into the shops here. I don't have any shops as, I don't really have trust in most mechanics.

you might wanna try these guys on the south side of San Antonio:  https://www.spitfireautoelectric.com/

You SIR, ROCKS! I'll definitely give those guys a try!

albertj wrote:

AA wrote:

Depends on the shop. Something so simple like that, they might do it for free. It would only take 5 mins to plug in and read the speed while driving.

Come to think of it you could get a scan dongle off eBay and download scanner software. If you don't have a scanner to read codes etc., might be time to get one.

You can get one for wifi, bluetoothor wired.   They either come with software or instruction s on how to get it for free/cheap.  The $$ software is a bit more capable but not as good as a genuine Tech II.

I will have to look further into getting a scanner. I have a hard time trusting those guess on EBAY. What are the chances of getting screwed over or getting something that looks nothing like the pic?

Best bang-for-buck scanner, imo, is Aeroforce Interceptor: http://www.aeroforcetech.com/products_order_gm.html

Keep in mind, a "code reader" is not the same as a scan tool. A code reader only displays and clears trouble codes - pick for $15-20 at Walmart (or visit AutoZone for free). For $50-up you can get something that shows real time parameters, and for $200-up, you can data log and playback parameters. For $350 you can log and download data with HPTuners scanner. For $500 you can have a complete scanner/tuner package to actually modify settings in the car's PCM.

More scanner information can be found here: https://rivperformance.editboard.com/t2100-faq-good-scanner-tuner-software-to-use

9ty7rivi wrote:

albertj wrote:

AA wrote:

Depends on the shop. Something so simple like that, they might do it for free. It would only take 5 mins to plug in and read the speed while driving.

Come to think of it you could get a scan dongle off eBay and download scanner software. If you don't have a scanner to read codes etc., might be time to get one.

You can get one for wifi, bluetoothor wired.   They either come with software or instruction s on how to get it for free/cheap.  The $$ software is a bit more capable but not as good as a genuine Tech II.

I will have to look further into getting a scanner. I have a hard time trusting those guess on EBAY. What are the chances of getting screwed over or getting something that looks nothing like the pic?

About zero. I posted ones I or my friends had bought over the years to do basic code pulling and drive-time logging. OBDII scanners are not expensive. The money comes in scanners that correctly interpret the OBDII codes that manufacturers have specifically used for one thing or another instead of their generic purpose. Not an issue for this. As for getting screwed that 's why I did not post a cloned Tech II.

AA wrote:

Best bang-for-buck scanner, imo, is Aeroforce Interceptor: http://www.aeroforcetech.com/products_order_gm.html

Keep in mind, a "code reader" is not the same as a scan tool. A code reader only displays and clears trouble codes - pick for $15-20 at Walmart (or visit AutoZone for free). For $50-up you can get something that shows real time parameters, and for $200-up, you can data log and playback parameters. For $350 you can log and download data with HPTuners scanner. For $500 you can have a complete scanner/tuner package to actually modify settings in the car's PCM.

More scanner information can be found here: https://rivperformance.editboard.com/t2100-faq-good-scanner-tuner-software-to-use

+1 this.

Our recently purchased '98 has this same issue where the speedo only reads up to 55, but our tach is also affected. The tach is sluggish and only reads up to 1100. The car seems to drive well with appropriate shifting. Our windshield washer fluid low light is on as well, with a good supply in the reservoir. This might be a separate repair, but could it be related? Lovin' this site and all the great info!

Bfid wrote:

Our recently purchased '98 has this same issue where the speedo only reads up to 55, but our tach is also affected. The tach is sluggish and only reads up to 1100. The car seems to drive well with appropriate shifting.  Our windshield washer fluid low light is on as well, with a good supply in the reservoir. This might be a separate repair, but could it be related? Lovin' this site and all the great info!

First thing to do is to try the approach outlined in this thread.  This problem is identified in this thread, but is not common at all. I'd appreciate/recommend that you do the troubleshooting and then report back.