dreroc-z

Alrighty so I have an 89 IROC and my gauges are all incorrect but they work. My speedometer is about 10 miles too high until about 50 mph then I couldn't even tell you where it goes after that. The oil guage either doesn't move or just bounces up and down. The total miles driven on that car move wayyy too fast (lets say I take a one mile drive...it shows that I just put ten miles on the car). My gas is off also I'm not really sure how it reads on a full tank it looks like it goes past the full mark then it reads whatever it wants to. Anyone have this problem? What is the repair for it? A new cluster?

I heading over to a junkyard sometime this week and they have 3 different 3rd gens there, hopefully one from which I can find a different seat belt because my passenger belt has seen its final days. Would it be worth to try out a cluster from one of these cars if I can find a decent looking one or is there a few things I should try on my own cluster? I would mainly like to just know the correct speed I'm going.

Someone point me in the right direction.

system155

U got to replace the whole cluster and the speedometer is off b/c u have way big tire and or the speedo gear

navy02ws6

Yep, sounds like you've either got the wrong size tires mounted, or someone has changed the rear-end gear ratio. Either way, you'll need a new transmission speedometer gear to match your tires and/or rear-end ratio.

dreroc-z

Hmm I will look into that. I have just the stock 16 inch rims...and the tires look pretty standard. I will go check the sizes and ratios in a little while and post them here because I'm not all that familiar with this stuff. As for the other gauges the whole cluster needs to be replaced then.

navy02ws6

Check the white RPO label in your center console (assuming that it hasn't been removed by someone). If you see the code "QDZ" or "QLC", then your car should have size 245/50/16 tires to have the speedometer read correctly. If you see "QPH" or "QYZ", then your car originally had size 215/65/15 tires, and that's likely what speedometer gear is still in the car, giving you an inaccurate reading. This is of course all assuming that a 215/65/15 tire is overall a different size than a 245/50/16...I suck at math, or I'd try and figure out that one for you.

See here for checking rear-end gear ratio http://www.ehow.com/how_7588196_calc...ear-ratio.html

I'm afraid I know stock 4th gen gear ratios a lot better than stock 3rd gen ratios. Your original ratio will depend on your transmission and options. Could be 2.73, 3.08, 3.23, possibly others. I think they had already stopped offering 3.73s by '89, I want to say those were only available in the earlier 5 speed cars.

scottmoyer

Being off by 10mph is not attributed to the tire size Navy02ws6 mentioned. The 16" tire has an overall size of 25.6" while the 15" tire is 26". The less than 1/2" difference may change the speedo by 2mph at most.

kennyjames

I have had the same issue with my fuel gauge. Oddly enough it only happens at random and is not a frequent issue. Occurred maybe 3 days out of the 6 months I've owned my S. It would read empty often during those days, when I clearly had plenty of fuel. I'm curious if yours is as random as mine. I find it also is affected by how I'm driving, if I run it hard the gauge reading will vary by a quarter tank or more until I mellow out. Hopefully this is common to more than just yours and mine, especially since you already replaced sensors.

l_dis_travlr

Update your profile, so we know where you are.

In most major cities, you can find a speedo/instrument repair shop
that can test/service the inst. cluster. You may have to go find some
used clusters for replacement parts, but then you can be confident that
the cluster works properly. (As opposed to the array of sender's, etc.)

Good luck, & keep us posted.