FE just keeps droping no matter how much I hypermile

[txe5502]

Originally Posted by R.I.D.E.

Bought a 99 Maxima for my wife brand new, when the 2000 Models were out. Paid for it with a check for $18,500.

One of the best cars we ever owned, except for the crap tires.

The history of your car consists of soo many disastrous events, diagnosis would be difficult, but I worked on them for 30 years, so maybe you should pay attention to my original post.

Nissan Mass Air Flow Sensors deteriorate with age, a very slow process which makes them gradually send a leaner signal to the ECU. In most cases the CEL will not come on until the car is alomost undriveable.

Born in 1950, and I had the unfortunate task of fixing what other "mechanics" had either destroyed or simple given up and told the owner they couldn't help them.

The most recent case involved a 2000 Ford Focus that had been to two dealers, with over $1000 in repairs with no change in the symptoms.

Hard to start, lack of power, poor fuel mileage, points to MAF. Of course with the sorry history of loaned to a friend who is soo stupid he doesn't even know which fuel to put in the tank, wrecked and not repaired, with possible alignment problems, blah, blah, blah, etc.

Then when you decide you can't afford to repair it unless we offer you some miracle solution, you have made the situation exponentially more difficult. It reminds me of the less than 1% of my customers who presented me with similar situations, and my advice that they take the car to someone who would fix it for free, yesterday, and smile at them when they picked it up, knowing their business life expectancy was measured in weeks , working on charity cases.

I could fix your car. In 30 years I never met one I couldn't fix------NEVER.
I also was NEVER summoned to court to answer for my actions, NOT ONCE IN 30 YEARS.

All that being said, and expecting your response to be very degrogatory, I will repeat myself only once.

Assuming it is not due to the diesel fuel, alignment, physical damage to components due to the wreck, more blah, blah, blah.

THE AFM IS YOUR BEST GAMBLE, AND YOU CAN BET IT IS A GAMBLE.

Flame away at me, looks like the old man has basically told you it was your problem, and probably for a good reason.

regards
gary

I double checked some things the other day and I noticed there is a clamp on the rubber boot from the MAF to the throttle body and it was loose as a goose! I tightened the clamp while the car was running and I noticed a slight increase in RPM for a split second just as it got tight so also maybe this was a problem that may be creating a false reading from the MAF due to air leaks behind it.

But whatever is wrong, I know I HAVE to fix this transmission problem before I can so anything else! FE issues with this car are now officially the least of my worries until further notice! I will fix this transmission problem and when it is fixed I will measure my FE again and report back here.

[GasSavers_D_K]

The shifting problem sounds similar to what happened to my school's drives ed car. It would shift way up in the rpms and would jerk the s**t out of the car. I think it turned out to be a problem with the ECU or PCM or something (I'm not too car savvy) and had to be reprogrammed.

[txe5502]

Oh no reprogramming! I have not found anything for my car that can do that! All I can seem to find it for is Ford/GM/Chrysler/Honda!

I hope this is not the case!

[theholycow]

It might be easier/cheaper to just get a transmission computer from a junkyard car than to try to get yours flashed. However, I'd look for other causes first; it could be the TPS, as you mentioned, for example.

[txe5502]

I got lucky, it was just a bad Throttle Position Sensor. I replaced that and it shifts fine now. Also that seems to be where all my power went. It has all the power it had before. Possibly my FE problem. I will just see.

[txe5502]

Ok update on this old old old thread. The Automotive Mechanics teacher at Davidson County Community College said to me it sounds like maybe I have a seized stator in my torque converter (I really hope not).

I have already discussed this with some other people and they tell me that would be like riding the brakes (the feel of it). It dont feel like this at all.

HOWEVER,
I have reason to believe this COULD be the case. (I know you people will think I am stupid for this but between school, (at the time, work), and lots of other things I didnt really have much time to fix it, and thats my only car.) Anyway, for about 2 weeks, maybe 3, I had TWO seized front brake calipers, I literally could not get past 2nd gear and it took near 3/4 throttle to just go 55 MPH. I drove like this for about 2 or 3 weeks till one of the rotors cracked from overheating, and then I had to just miss a day of school and fix it.

This is the reason I think maybe the Automotive Mechanics teacher is right in saying that maybe its a fried Torque converter, but I really hope its not this!

Does anyone know anything about this? Is there any way I can test this?

Thanks,
Tyler Guy

[soletek]

Originally Posted by txe5502

Ok update on this old old old thread. The Automotive Mechanics teacher at Davidson County Community College said to me it sounds like maybe I have a seized stator in my torque converter (I really hope not).

I have already discussed this with some other people and they tell me that would be like riding the brakes (the feel of it). It dont feel like this at all.

HOWEVER,
I have reason to believe this COULD be the case. (I know you people will think I am stupid for this but between school, (at the time, work), and lots of other things I didnt really have much time to fix it, and thats my only car.) Anyway, for about 2 weeks, maybe 3, I had TWO seized front brake calipers, I literally could not get past 2nd gear and it took near 3/4 throttle to just go 55 MPH. I drove like this for about 2 or 3 weeks till one of the rotors cracked from overheating, and then I had to just miss a day of school and fix it.

This is the reason I think maybe the Automotive Mechanics teacher is right in saying that maybe its a fried Torque converter, but I really hope its not this!

Does anyone know anything about this? Is there any way I can test this?

Thanks,
Tyler Guy

About the torque converter: I doubt that the teacher at your community college doesn't understand how a torque converter works. Therefore, I think you must have misunderstood what he said. The term stator means stationary. This is the one of the three segments in a torque converter that splines to the stator support, the snout sticking out of the front of the transmission that is bolted solidly to the front of the transmission case, it does not turn. This is how it works:

The expanding gasses in the combustion chamber turn the crankshaft. Bolted to the rear of the crankshaft is a flexplate, the torque converter body is bolted to the flexplate. Welded to the inside rear of the torque converter (in a radial/helical pattern) are the impeller fins. As the torque converter is turned by the engine, the transmission fluid is picked up by the impeller fins and thrown at the stator fins which in turn, due to their curved shape (like a portion of a nautilus shell) accelerate the velocity of the transmission fluid which impacts the fins on the turbine causing the input shaft of the transmission (which it is splined to) to turn. This condition is called vortex flow. A vortex is the path the fluid takes as a series of small circles traveling in a large circle. It is also known as torque multiplication. When you start off from a stop (for simplicity's sake lets say your engine is putting out 100 lb/ft of torque) the redirection of the tranny fluid off the stator increases the input force supplied by the engine at a 2.1:1 ratio. This means that the input shaft of your automatic transmission is seeing 210 ft/lbs of torque. Once the engine rpms and transmission rpms come close to matching each other's speed, torque multiplication is no longer needed. Centrifical force keeps the large majority of fluid toward the outside of the torque converter. This state is known as rotary flow. At cruise speed, while in rotary flow, you have what is known as a fluid coupling. It is not a direct drive and it leaves you with about 10% slippage. They came up with "lock-up" torque converters to eliminate that slippage and to increase engine efficiency. Now you can see that if your stator broke away from the stator support, and is turning, it is no longer redirecting the fluid at the turbine as it should be and might even be directing the fluid at the front of the torque converter housing causing it to baloon. That is a very bad thing. It can even push your crankshaft forward so hard it can melt the babbit out of your thrust bearing and I've even seen them tweak the main webbing in a block. On top of that I've seen them melt the babbit out of the adjascent connecting rod bearings. Your engine may not be powerful enough to do that kind of damage to itself, if indeed, this is even your problem at all. The only real way to tell is to remove your torque converter and have it inspected by a transmission shop where they know what they are looking for. Otherwise, just replace it with another torque converter. Since this is probably very uncommon with these vehicles, you can likely find a replacement in a wrecking yard.

I hope this helps, and good luck.

By-the-way, you need to get on to repairs immediately. By not fixing your brakes in the first place has probably created the additional problems and expenses you are facing.