No power/Bad gas mileage

[95SevilleSLS]

Actually the car does jerk when I stop, it is impossible to make it stop smoothly. It didn't do it when I first bought it. And the reason I found out my rear brake was hung up because of the parking brake cable was because I was smelling burning. But obvousily that was fixed last year.

It's weird but my 93 with 132,000 miles is in a lot better shape then my 02 with 87,000 miles. That's what you get for buying a car from a rich doctor I guess. I've noticed that rich people tend to not care about their car as much and just drive them until something breaks and then buy a new one because they can afford it. I think I'd be better off trying to get what I can out of the car and looking for a local car that an older person had, just like my 93. One that has not been around a big city.

I preformed a stall test and it would not go higher then 1900 RPM. So that didn't help me much. What are these supposed to be?

My father-in-law who used to be a GM mechanic told me how a torque converter worked and that has got to be the coolest thing in the world. It's just amazing how they work. What would cause a torque converter to fail to prematurley? A lot of city driving? Or just a fluke from manufacturing?

I just think you're right, bodybyfisher, I really think the torque converter is the root of my problems. Reading all of these things is just like describing my problems.

[BodybyFisher]

The stall speed seems ok based on the torque converter 101 article:

While pressing firmly on the brake pedal with your left foot, use your right foot to press down on the accelerator pedal. Increase engine speed until engine rpm will go no higher. Then release the accelerator pedal and allow the engine to return to idle. Note the maximum stall speed rpm (typically 1,500 to 2,200 rpm) and compare to specs.

If the engine stall speed is higher than specifications, the transmission is slipping (probably a holding clutch or band).

If the engine stall speed is lower than specifications, the torque converter is defective (stator is slipping), or the engine is not producing normal power (engine problem).

Can you rev the engine in neutral? See this

Sometimes a stator wheel will hang up and remain locked at high speed. If this happens it will act like a speed brake, causing the torque converter to fight against itself. The car may start out and drive normally at low speed, but as speed starts to build the engine will strain harder and harder to overcome the resistance. If the engine won't rev much beyond 3,000 rpm in neutral, the stator is definitely hung up

If you are jerking to a stop check your brakes something does not sound right. Smell your fluid, have we done that? Make sure you are not starting in second gear.

[95SevilleSLS]

The stall speed seems ok based on the torque converter 101 article:

While pressing firmly on the brake pedal with your left foot, use your right foot to press down on the accelerator pedal. Increase engine speed until engine rpm will go no higher. Then release the accelerator pedal and allow the engine to return to idle. Note the maximum stall speed rpm (typically 1,500 to 2,200 rpm) and compare to specs.

If the engine stall speed is higher than specifications, the transmission is slipping (probably a holding clutch or band).

If the engine stall speed is lower than specifications, the torque converter is defective (stator is slipping), or the engine is not producing normal power (engine problem).

Can you rev the engine in neutral? See this

Sometimes a stator wheel will hang up and remain locked at high speed. If this happens it will act like a speed brake, causing the torque converter to fight against itself. The car may start out and drive normally at low speed, but as speed starts to build the engine will strain harder and harder to overcome the resistance. If the engine won't rev much beyond 3,000 rpm in neutral, the stator is definitely hung up

If you are jerking to a stop check your brakes something does not sound right. Smell your fluid, have we done that? Make sure you are not starting in second gear.

I have smelled my fluid and it doesn't smell burnt. I'll check again tomorrow. I'm positive I'm starting in 1st, it just takes a lot of effort to get going. I tried revving it in neutral and it went to 4 grand and hit the limiter with no problem.

The best way to describe how it feels is that I feel like I'm towing something all the time. I get crappy mileage, it won't stop smoothly, it decelerates faster then normal, it seems, when I let off the gas, and it take a lot of throttle to get the rpms up and get going. Even though I "passed" the stall test, couldn't I still have a bad torque converter?

[BodybyFisher]

If your converter stator was slipping your stall speed would be lower than 1900 and you checked to see if it was locked by reving the engine beyond 3000 rpm. You did however say some thing interesting, you said you went to 4000 grand and hit the limiter with no problem. When did it hit the limiter? Keep in mind that your engine (an STS) has a 6800 rpm red line, you should not have hit any limiter at 4000. Nor would you want to rev to 6800 in neutral. What limit did you hit that you thought you hit a limiter?

Does anyone know if the NS has a limiter built in if you rev the engine in neutral?, I don't think so.

[95SevilleSLS]

If your converter stator was slipping your stall speed would be lower than 1900 and you checked to see if it was locked by reving the engine beyond 3000 rpm. You did however say some thing interesting, you said you went to 4000 grand and hit the limiter with no problem. When did it hit the limiter? Keep in mind that your engine (an STS) has a 6800 rpm red line, you should not have hit any limiter at 4000. Nor would you want to rev to 6800 in neutral. What limit did you hit that you thought you hit a limiter?

Does anyone know if the NS has a limiter built in if you rev the engine in neutral?, I don't think so.

I think the newer ones have a limiter so that you don't sit there and rev it too high. Somebody else had mentioned it earlier.

[jking220]

IMHO there must be a problem with the rear brakes...even if there was a torque converter issue, would you expect this to cause the issues described...the torque converter wouldnt cause it to slow quicker unless you were at higher speeds...and I wouldnt think it would cause it to not "stop smoothly"...and it wouldnt cause the rear tires to stop spinning immediately after spinning them in the air...I would go after the brakes first...seems much cheaper/easier.

JMO

[BodybyFisher]

IMHO there must be a problem with the rear brakes...even if there was a torque converter issue, would you expect this to cause the issues described...the torque converter wouldnt cause it to slow quicker unless you were at higher speeds...and I wouldnt think it would cause it to not "stop smoothly"...and it wouldnt cause the rear tires to stop spinning immediately after spinning them in the air...I would go after the brakes first...seems much cheaper/easier.

JMO

Given that the stall speed was 1,900 the converter did NOT appear to be a problem, and that Dusty noted for the first time that the car jerks to a stop we were off the torque converter as a cause but thanks for noticing.

But if his engine speed is not intentionally limited to 4,000 rpm in neutral, we have NOT fully eliminated the converter, as a locked stator would drag his performance down. This is why diagnostics are done, its a process of elimination. Keep in mind that until he noted the jerk to a stop, all of the other symptoms he DID mention pointed toward torque converter. I have not heard anything regarding smoking brakes, glowing rotors, he was able to turn the wheel by hand, etc. The diagnotics are still underway, but the jerk to a stop is very telling that the brakes need to be looked at.

Dusty you used a digital thermometer didnt you, if I recall you did not see a big differential between the front and back, is that correct? Have you checked the rotor temp after a long ride?

[95SevilleSLS]

IMHO there must be a problem with the rear brakes...even if there was a torque converter issue, would you expect this to cause the issues described...the torque converter wouldnt cause it to slow quicker unless you were at higher speeds...and I wouldnt think it would cause it to not "stop smoothly"...and it wouldnt cause the rear tires to stop spinning immediately after spinning them in the air...I would go after the brakes first...seems much cheaper/easier.

JMO

Given that the stall speed was 1,900 the converter did NOT appear to be a problem, and that Dusty noted for the first time that the car jerks to a stop we were off the torque converter as a cause but thanks for noticing.

But if his engine speed is not intentionally limited to 4,000 rpm in neutral, we have NOT fully eliminated the converter, as a locked stator would drag his performance down. This is why diagnostics are done, its a process of elimination. Keep in mind that until he noted the jerk to a stop, all of the other symptoms he DID mention pointed toward torque converter. I have not heard anything regarding smoking brakes, glowing rotors, he was able to turn the wheel by hand, etc. The diagnotics are still underway, but the jerk to a stop is very telling that the brakes need to be looked at.

Dusty you used a digital thermometer didnt you, if I recall you did not see a big differential between the front and back, is that correct? Have you checked the rotor temp after a long ride?

When I checked the rear left brake, the parking brake was not holding it anymore and also you could move the caliper back and forth a little bit on the pins after a little wiggling so there doesn't seem to be a problem there.

I did check the brakes with an infared thermometer. At an ambient temperature of about -5 degrees the front brakes were 40 degrees and the rear brakes were about 80 degrees. That was after just a little bit of in town driviing. But like you said, the front brakes are vented, so they should be cooler, right?

[BodybyFisher]

You checked both rears and they were about the same temp? I would keep checking the temps of the rear vs the front, take it for a rough ride and check it. It certainly seems like you are having some type of mechanical drag. I would think if you had a mechanical drag in your rear brakes they would be hotter than that.

[jking220]

If you are jerking to a stop check your brakes something does not sound right. Smell your fluid, have we done that? Make sure you are not starting in second gear.

Sorry BBF...I guess I missed this part of your post... I was not trying to second guess your diagnosis... You are definately a "the man" on this site.

Sorry

[BodybyFisher]

If you are jerking to a stop check your brakes something does not sound right. Smell your fluid, have we done that? Make sure you are not starting in second gear.

Sorry BBF...I guess I missed this part of your post... I was not trying to second guess your diagnosis... You are definately a "the man" on this site.

Sorry

No you were not second guessing, you picked up what the diagnosis had uncovered and we needed a summary at that point. Refocusing the thread once in a while is smart. Oddly, its not 100% clear that his brakes are causing this, I am kind of stumped at this point, any ideas you have are welcome, Thanks

[95SevilleSLS]

If you are jerking to a stop check your brakes something does not sound right. Smell your fluid, have we done that? Make sure you are not starting in second gear.

Sorry BBF...I guess I missed this part of your post... I was not trying to second guess your diagnosis... You are definately a "the man" on this site.

Sorry

No you were not second guessing, you picked up what the diagnosis had uncovered and we needed a summary at that point. Refocusing the thread once in a while is smart. Oddly, its not 100% clear that his brakes are causing this, I am kind of stumped at this point, any ideas you have are welcome, Thanks

It's nice to know I'm not the only oen that's stumped!

I'm still thinking it may be the converter though because of a few things:

When I go on our bypass around town (speed limit 55 or so) the tach fluctuates between 1800 and 2200 RPM like it can't just lock the torque converter in and leave it there. That's about when my P0741 code kicks in...sometimes. When I took that exact same road with the DTS, the torque converter locked in and it stayed at 1800 RPM. Once again it's acting like something is holding it back and it can't get enough power to go up the slight incline with the torque converter locked in so it has to unlock it. I don't know if that helps, but I thought I'd just throw that out there.

How much would it be, about, to get a torque converter replaced? That would solve me P0741 code too more than likely, right?

[Texas Jim]

It's nice to know I'm not the only oen that's stumped!

I'm still thinking it may be the converter though because of a few things:

How much would it be, about, to get a torque converter replaced? That would solve me P0741 code too more than likely, right?

Dusty,

It would not help solve the code if there is SOMETHING ELSE holding it back and making it work hard. That could be enough to unlock the torque converter. There is a possibility you would be wasting your money if there is really something else holding it back.

You mentioned once... that it kinda jerks when you stop. We need to find out what is causing that. It is not normal

Have you tried this? Or maybe a better question... WILL you try this?

If you are rolling on a level area.... like a parking lot, at about 5 to 10 MPH ... and you put it in nuetral and killed the engine... does it stop pretty quick, or does it keep rolling nice and easy like it should? If it stops fairly quickly and fairly sudden... your first idea about a brake dragging may have some validity and will need further exploration.

[BodybyFisher]

Good Idea Jim

[Texas Jim]

Good Idea Jim

Thanks

[caddypete]

As for free reving the engine in park or nuetral, I do believe there is a limiter for that. I know I have had my engine rev and it will hit somewhere around 3500 rpms and stop, then rev up and stop even though pedal is still depressed

[95SevilleSLS]

It's nice to know I'm not the only oen that's stumped!

I'm still thinking it may be the converter though because of a few things:

How much would it be, about, to get a torque converter replaced? That would solve me P0741 code too more than likely, right?

Dusty,

It would not help solve the code if there is SOMETHING ELSE holding it back and making it work hard. That could be enough to unlock the torque converter. There is a possibility you would be wasting your money if there is really something else holding it back.

You mentioned once... that it kinda jerks when you stop. We need to find out what is causing that. It is not normal

Have you tried this? Or maybe a better question... WILL you try this?

If you are rolling on a level area.... like a parking lot, at about 5 to 10 MPH ... and you put it in nuetral and killed the engine... does it stop pretty quick, or does it keep rolling nice and easy like it should? If it stops fairly quickly and fairly sudden... your first idea about a brake dragging may have some validity and will need further exploration.

Sounds good, I'll try that out. Only bad thing is we don't have a level area because of all the snow and ice around. Wish I could borrow someones heated shop...

I have another idea to try untop of that. Put the 93 deville in neutral with the engine off and try to push it. Put the 2002 STS in neutral with the engine off and try to push it. Both cars are about the same weight, it should take as much effort to push the 93 as it does the 2002, right?

[BodybyFisher]

If you have a brake dragging that badly, I would imagine it would slide and not turn on ice and snow

[95SevilleSLS]

I really don't think a brake would have to be dragging THAT much to cause a drop in fuel economy/get up and go.

I did a few test tonight and this is what I came up with:

In a car dealership I let it roll at about 7 MPH and it seemed to roll fine until it slowed down more, then it felt like someone put it into first or something. With the engine off it did not do this.

I pushed the car with it running and with it not running in neutral and it pushed exactly the same way both ways. It was difficult to get it going and then it was fine, but part way through it felt like someone got in and slammed on the brakes and it was VERY difficult to get it to keep going. I had to give it all I had just to keep it going and then after a little bit it would let up again.

I let the car idle on a flat level surface in drive and it went 3 MPH.

I came to a slight incline and braked the car to a stop. I let go of the brake and the car started to creep forward and then just stopped. I just touched the gas to get it slightly rolling again and then it just stopped again. I kept trying different ways of starting and stopping and it just kept seeming like there was one "spot" where something was holding it.

I came home and checked the wheels. The front two brakes were about 60. The drivers side rear was about 78 or so and the passenger side rear was about 93. The passenger side is the one that was hung up last year and also the wheel that I spin and it just stops. (I earlier said it was the left side, but I meant it was my OTHER left )

This is my theory, I may be completely wrong, but it's worth a shot.

I used the parking brake last May or so to try and burn out (yes, I am a retard) and it probably had never been used before and got stuck on the passenger side. I noticed really bad mileage and really bad power, but thought it was the catylitic converter and left it be for a couple months until one day I smelled something burning. I checked the wheel and it was 400 degrees so I took off the wheel and pounded back the spring that the parking brake hooks too. Then I noticed that the rotor was very warpped because it vibrated badly when I pushed on the brakes.

Now onto the theory: The rotor is so warpped that it gets hung up every time it comes around the part of the rotor causing bad mileage/power.

Also another thing is when I used to drive around 50-55 I would get 30 MPG instant and now it's reading 24 MPG.

How does that sound? Stupid? It's all I have right now.

[Texas Jim]

I came home and checked the wheels. The front two brakes were about 60. The drivers side rear was about 78 or so and the passenger side rear was about 93. The passenger side is the one that was hung up last year and also the wheel that I spin and it just stops. (I earlier said it was the left side, but I meant it was my OTHER left )

Now onto the theory: The rotor is so warpped that it gets hung up every time it comes around the part of the rotor causing bad mileage/power.

How does that sound? Stupid? It's all I have right now.

I think you may have found the problem. Jack up that wheel... try turning it by hand and see if it stops, or tries to, at the same spot. If it does, the rotor is warped enough to be causing significant drag. That would also explain the higher temp of that rotor.

If this is correct.... replace rotor.

[Ed Hall]

My 93 Northstar powered Allante also jerks when you're coming to a stop because the transmission is shifting from 2nd gear to 1st gear.

[Ranger]

I came home and checked the wheels. The front two brakes were about 60. The drivers side rear was about 78 or so and the passenger side rear was about 93.

Also another thing is when I used to drive around 50-55 I would get 30 MPG instant and now it's reading 24 MPG.

This is a brake issue. Either a caliper hanging up and dragging or a warped rotor. That's my story and I'm stick'in to it.

[95SevilleSLS]

Cool! I'm glad you guys are thinking the same thing. Luckily it's going to be about freezing this weekend so I can work on it. Is it difficult to replace the rotor or just as easy as any other GM? If I replace one, I think I might as well replace both and the brake pads also.

[BodybyFisher]

Cool! I'm glad you guys are thinking the same thing. Luckily it's going to be about freezing this weekend so I can work on it. Is it difficult to replace the rotor or just as easy as any other GM? If I replace one, I think I might as well replace both and the brake pads also.

I would while you are there why not. Don't forget to get the proper slider lube and clean and lube the sliders and bushings. Use either the LUBE from the dealer or equivalent, not the cheapo stuff on the parts counter in the little DUCK SAUCE packages....

[Ranger]

I was thinking about this on the way to work and the more I think about it, the more I doubt it is a warped rotor. For the rotor to be warped enough to cause a drag, I would think you'd feel a vibration and braking would be somewhat akin to a jack hammer. I still suspect a dragging brake though.