OK, tired of searching for this one. I have an RPM problem. I have 3.42 gears/700R4 tranny in my 1990 RS. Problem is that I am turning 3000 RPM when I am going 55mph. I can manually shift through all gears and I can see that the torque converter is locking up. The calculators say I should be running 2450 at 80mph. I know the speed is right. I have the correct spedo gears in the tranny. I have put in a second new transmission with a new torque converter. The problem still exist after the second new tranny. The only thing I can think of that might be the problem is the VSS. I don't know much about the VSS though. Please someone tell me (and mean it too )that the VSS could be my problem. Does this sound right? Thanks

 

The VSS just sends a signal to the computer to let it know how fast your going.

 

Nope. Sorry man, you've got problems elsewhere.

 

What else could it be? Bad Tach or maybe bad distributor?

 

Are you using a factory tach? They're not especially known for their accuracy.

 

It is the factory tach and stock distributor. Do you have any idea how I could test the tach? Maybe have another tach hooked up at the same time or can a shop do that?

 

A shop could definitely do that for you.

But, if you want to do it yourself, the easiest thing to do would be to find someone local with a scan tool, hook it up to your car, and see what RPMs the computer is reading. If you want to drive to Greenville, SC, I'll be more than glad to hook up my scan tool to your car . You could also hook up a cheap Sunpro or Autogage aftermarket tach from an auto parts store and compare the RPMs between the 2.

 

That's a good idea. I think I will go to a hobby shop on Pope AFB and see if they can do it for me. Rule out some stuff!

 

the vehicle speed sensor has alot more to do with how the car run than you think.
Without a VSS, the Chevrolet Fuel Injected engines will not run correctly, and they will not pass a smog test.

Basically, the VSS tells the ECM how fast the vehicle is going. Most people think the VSS is only used for the lock-up torque converter. The VSS is also used to control the EGR valve, the charcoal canister purge valve, the electric cooling fans, idle speed, and air/fuel ratio. This is all explained in the Chevrolet shop manuals.

It must be emphasized that the VSS is used to control the idle speed when the vehicle is moving. Without the VSS, a vehicle may have stalling problems under certain conditions. Needless to say, this is dangerous. Raising the minimum idle speed with the adjusting screw can eliminate stalling, but the engine will still not run optimally without a VSS.

read the link i have posted below, alot of information on the vss

VSS ARTICLE

 

Now THAT is exactly what I was hoping to hear. Thanks Quickstyle you have given me hope. I think I will replace this thing now and see if that fixes my problem.

 

OK, I went to buy a VSS and came across this problem: Does my car come with the option D8F or D8I?????
Well if it did then the VSS is $29.99 if not then it is $53.99. Any ideas?

 

Look at you RPO codes in the rear locking storage compartment. See which one out of the 2 you have.

 

Well, I finally bought the VSS and installed it and it did not fix the problem. I am running exactly 54mph at 3000 rpm. This is definately not right. Could the distributor be doing this? Or, could this simply be my shift points are out of whack and if so can they be adjusted? Thanks

 

i believe that 90 rs camaros came with 2.73 gears in the v8 and 3.23 in the v6. so i assume you change the rear to the 3.42.... if you did, you had to change the speedometer gears also... not just the gear on the end of the vss (driven gear), but the drive gear inside the tranny too. the drive gear should be 15 tooth and the driven gear should be 40 tooth if you have the 3.42 rear end. the original speedo gears should have been 17/36 tooth. let me know if you change both of these or not, and what tooth you put in, you might actually be driving slower than your speedometer reads. i know when i went from 2.73 to 3.42 i was reading 100 mph at around 60 actual mph.

 

You are correct about the original gears, and I did swap the gears to 3.42. I also swapped out both gears for the speedo but the problem is the rpm. My speed is dead on but my rpm's are high. I am beginning to think that maybe it is the torque converter. I may have to switch back to my original torque converter.

 

Is your TCC locking up?

 

https://www.thirdgen.org/newdesign/t...ueswitch.shtml
go to that link and see if that changes the way the rpms are effected.... if the rpms comes down to where you think they should be, then your torque converter is not locking up. if it does not change at all then the torque converter is ok.

 

when you manually shift down into d(from od), does anything change? you may be in 3rd gear not 4th.

 

My torque converter is locking up I can see the 200-300rpm drop in OD. It does drop into 3rd too. I have talked to some transmission shops lately and they think my torque converter is doing it. They both suggested going back to a stock converter. I hate to think that B&M has such sh1tty converters that two in a row will not work for me but, I don't have much else that I haven't tried so I am going to go buy a stock converter and put it in to see if it fixes it. I don't want to use my old one because it may contaminate my new tranny.

 

did we ever verify engine rpm?

 

Nope, good point. I completely forgot about doing that. That shouldn't take long to do either. I'll have to go to my hobby shop to do that though. Thanks

However, for what it's worth, it feels like the rpm's are right.

 

you should probably do the test i mentioned above before changeing your converter, its a simple test that only takes 5 mins. alot easier than changeing the converter before you know for a fact that it is the problem.