Alright. I drive a '91 z/28, 305 TPI. 700r4 automatic. Car will shift into all the gears normally, but at 60 mph I'm at 25-2700 RPM. That seems excessively high, considering my old v6 700r4 cruised at sub 2000 at 60mph. Running 2.73 gears currently. Is this a normal RPM for highway speeds with a 305 TPI, or is something going wrong here?

Anybody?

running stock tire size? Gotta check, but are you sure about gear ratio?? and is it shifting into 4th (overdrive) gear?? If so you convertor might not be locking.

Stock tire size, yes it shifts into all gears.

maybe the convertor is not locking.....you can check by putting a switch connected with wires to both upper outside pins on your computer connector....when driving steady speed on interstate, flip switch to on position, if convertor locks then, it might be something wrong with computer....you should see a 200-400 rpm drop when covertor locks...

You can test converter lock-up at freeway crusing speeds by touching the brake pedal enough to turn on the brake lights but not enough to apply the brakes. As long as you are still on the throttle at a steady speed the converter will unlock when the brake lights come on and the RPM's should jump by about 300. Release the brake pedal and the converter should lock back up.

Guess not...

On second thought...maybe it's not. I was cruising about 55, steady throttle, tapped the brakes to turn the lights on and the RPM's jumped about 250.

Is it possible my tach is off? I doubt it, though...There's a definite difference in sound between 16-1700 and almost 3000.

my 350 cruises about 2300 to 2500 at 60mph but i only have a 3spd with 205/60/15 tires and 3.27 axel ratio

Um.

Ok.

Well. Pulled engine codes and got a low vacuum reading at the MAP sensor.

Might have something to do with it. Just maybe, though

Guess I'll be replacing that tomorrow.

I have read many articles about how bad our tachs are off.....you might check in to that too...might not be a bad idea...

I hooked up a standalone tach. Surprisingly mine is only off by 20 or 30 RPM.

Oh well, I work at a GM dealership, a new solenoid is only $14 with my discount, and I can get free shop time. Might as well replace it, because the MAP didn't fix it.

some of the tachs work okay....mine does too....try the solenoid and see what that does....maybe the speedo is off??

My TC isn't locking and at 60mph my RPM's is around 2,000 (3.27 gears). If my TC were locking like it's supposed to the RPM should be around 1800.

2500 seems very high, even with the TC unlocked.

My speedo is off, but I run a GPS all the time, so I know how fast I'm going. The speedo being off wouldn't cause it to run so high, would it? It reads ~13% higher than it should (reads about 60 when I'm going 50ish). I'd think all that would do would make my converter lock sooner.

True.....If your convertor is actually locking...then you shouldn't have any slippage....unless trans. is slipping badly.

Sounds like the trans is still in 3rd gear. The converter locks in 3rd gear too and that can be what you feel as the 3rd to 4th shift. Have you tried adjusting your TV cable? The valve in the trans that controls the 4th to 3rd kickdown may be stuck which wouldn't allow the shift to 4th.

I agree....I never thought of that....you might be in third....that would be a logical conclusion....

And I'm guessing that you installed the 2.73 gears yourself? These are definately not the stock ratio for a G92/1LE with a 305. IIRC the stock ratio should be a 3.42 with the 5 speed. Your RPM's sound about right if you had 3.73 gears, though.

I agree. Get it on the highway and drop it into 3rd, if it doesn't do anything you'll know.

This isn't my 1LE, that's running perfectly lol.

edit - I completely forgot, no, it does shift into 4th, I checked that last night. At 55mph, if I shift from o/d D (4) to regular D (3), the RPM's jump to about 4k. I'm thinking the solenoid just isn't working.

I would bet strong money that your tach is off. I've owned 3 91 Camaros and every single one had a tach that read high.

If you search for 91-92 tach fix you will find a thread on how to fix it.

I said in a previous post that I hooked up a stand-alone tach.

However, I have made in interesting discovery. I have a feeling my TV cable is not the right size.

Piece of evidence one: Previous owner tied a knot at the end of it, to shorten it. Not sure how I missed that earlier, but I took the knot out...which made it waaaaay too long and I was getting red-line shifts out of first gear at light throttle.

I've tried 4 different lengths, I'm not really sure how to determine if I have the right length or not, though. Right now it's set to shift to second at 5k RPM's under WOT conditions. Have to admit, it makes the amount of rubber a stock 305 can lay a lot more impressive

Would an incorrect length TV cable keep it from locking up? It still shifts into 4th gear, I dropped it into third going about 50 and the RPM's jumped considerably, so I know 4th is working correctly.

Well, I just adjusted it properly (fully extended at WOT) and it still won't lock.

I ordered a TC lockup solenoid at work and a new gasket ($20 total, employee discount is pretty awesome haha) so I guess I'll replace that when it comes in.

Well, the solenoid did not fix it.

Suppose that means the clutch in the converter is dead?

Alright.

So...the previous owner installed a stand-alone fan controller, which works correctly (I'm assuming, turns the fans on/off dependent on how hot the engine is) but, and yes I know this makes me stupid for not checking, disconnected the coolant temperature sensor. Reconnected it, temp. gauge works now (2 of my others had bad gauges, I assumed this was bad as well) temp gauge is working correctly.

Now when I hit 50 mph, I'm still turning just shy of 2500 RPM's, which is exactly what I was before. However, since I've replaced the solenoid, the converter now locks up (steady throttle, tap the brakes enough to turn the lights on, the RPM's will jump about 200).

Car is entering 4th gear.

Here's where it gets interesting haha. My tach is very, very slightly off. less than 100 at 5k RPM's. Converter is locking up correctly, but my tach is still reading high, and the engine sounds like it's spinning higher than the 1500 or so RPM's I should be at.

What's going on here? Because honestly...I am completely stuck. I suppose I'm going to pull the negative cable and reset the ECM, because that's about the last idea I've got.

Could, possibly, the stand-alone fan controller be affecting it at all?