Automotive Question

[Mikebits]

Okay, my 96 Pontiac Trans Am developed an attitude the other day. The power steering went out and it was hard as hell to steer, so I thought the worse, but something strange happened. Two days later I drove the car and power steering was restored, now how weird is that? How can a car repair itself? Is this a symptom of another failure or was it a computer glitch?

Any thoughts?

 

[Nigel Goodwin]

Is it electrical power steering?, if so they tend to have a thermal cutout, which disables it if it gets too hot. When it cools down, it works again.

 

[tcmtech]

You may have just had a small piece of crud stick in the pressure bypass valve on the pump. That would have given you basically no pressure to drive the power steering actuator. Most power steering systems have very tight clearances in the valving and rather poor or non existent filtering systems.

It could have just had a an air lock in the pump itself too.

 

[Diver300]

I'm no great expert on American cars, but electric power steering is rare. The only car that I know of with it is the MGF. Electro-hydraulic power steering is more common, but still only on small cars.

I guess that a '96 Pontiac would have power steering completely unaffected by any electrics, let alone electronics. There is likely to be a pump with a pressure relief. That will feed oil to a valve that controls the ram. The movement of the valve is controlled by the torque in on the steering wheel. The valve can feed the oil in either direction, a bit like an H-bridge. It is set to leave all the ports open with no torque, so that the oil flows freely and wastes as little power as possible when no assistance is needed.

Intermittent action sounds like a stuck pump valve or pressure relief valve. I would change the power steering oil and see how dirty the old stuff is. It could also be a flexible hose where the inner has come away and is stopping the flow. You can operate the pressure relief valve by holding the steering hard to one end and revving the engine.

 

[Nigel Goodwin]

I'm no great expert on American cars, but electric power steering is rare.

Fiat Punto's have it, and the manual specifically mentions the possibility of overheating and temporarily losing the power assist.

 

[Diver300]

Fiat Punto's have it, and the manual specifically mentions the possibility of overheating and temporarily losing the power assist.

Yes, but Fiat Puntos are a long way from '96 Pontiac. It would surprise me if the Pontiac has electric power steering.

 

[HiTech]

Some usfeul links for you to bookmark.


**broken link removed**

**broken link removed**

Pontiac GrandAm & TransAm Q&A website
WikiAnswers - Pontiac Trans Am Questions including "How do you replace the water pump and temperature valve on a 1998 Pontiac Grand Am"

1996 Pontiac Firebird Formula/trans Am recalls, safety ratings at CARFAX

 

[picbits]

If its hydraulic power steering then your fluid might be getting low or you might have had a slack fanbelt.

Other things that can happen is the alternator seized or stalls which kills the fanbelt causing the power steering to go as well - you tend to notice the noise and burning smell from the belt when this happens.

 

[Mikebits]

Thanks for the tips.

 

[Mikebits]

Well, just an update on this. This may surprise you but the problem was my water pump. It was freezing up and was causing the drive belt to screw up which in turn was messing up my power steering. I guess the engine always running very hot and a battery charge problem should have been a clue. With the new pump, my car starts right up, runs, steers, smooth and cool

It took me awhile to really look into it because it was intermittent, but last week it got real bad.

Man I love this car, to heck with GW.

 

[killivolt]

Well, just an update on this. This may surprise you but the problem was my water pump. It was freezing up and was causing the drive belt to screw up which in turn was messing up my power steering. I guess the engine always running very hot and a battery charge problem should have been a clue. With the new pump, my car starts right up, runs, steers, smooth and cool

It took me awhile to really look into it because it was intermittent, but last week it got real bad.

Man I love this car, to heck with GW.

View attachment 38310

You mean to tell me your not one of billions who will be driving this.


Air Muscle

I can't wait to hear the street racer's get hold of this powerful beauty. Then Watch their Giant burst of Speed.

 

[HiTech]

4 hours to fill the tanks with compressed air? What happens during a serious accident? Everyone with half a brain knows what happens to scuba tanks or compressed gas cylinders when they rupture --- a rocket to the moon! France should invent a car engine that runs off of cowardace.

 

[killivolt]

They had to work this one out before they could introduce it to the Market. Their solution was to use carbon fiber strong enough not to just rupture but breaks apart quickly releasing all the pressure.

Or so they say ?

 

[tcmtech]

Given the typical levels of redundant safety the high pressure cylinders are designed to its not really an issue. In an honest crash that tank is going to survive far better than the vehicle and driver ever will. To me tank explosions are not even an issue.

When was the last time any high pressure tank exploded and made it to the news any where in any recent history? They are more like plane crashes. You do hear about one now and then but given the incredible numbers of flights happening every day they are very rare. .

Its not impossible for high pressure tanks to explode but for the sheer numbers of them used in every day life most people are completely clueless to their existence let alone how many are around them at any one time. If they where as dangerous an where exploding as often as some people seem to think they are they would not even exist anymore. Even when trains derail the high pressure tanker cars are typically the ones that survive without spilling what they carried.

I scuba dive and the few honest stories of tank explosions are from situations where incredible neglect and unbelievable stupidity where combined and most these stories are decades old and come from the days long before standard service life and testing laws had been put in place. The most modern ones are from third world countries where little or no proper maintenance is used and untrained and unskilled people are doing what ever they feel like when they are filling their tanks.

The last scuba related one I heard was something that happened some years ago to some divers in some under developed country who wanted to extend their dive times by over filling there tanks to 5500 PSI instead of the normal 3000 PSI they where rated for being their pump could go up that high.
The safety relief valves could not be set to any more than around 4000 PSI so they just brazed them shut. The first tank that they pumped up to 5500 PSI was also the one that killed several people!
The investigation revealed that all of the tanks they had been using have had not been properly serviced or tested or re certified in many years as well. If that tank hadn't blown up the next one probably would have.

To me that doesn't mean all high pressure tanks are dangerous. It just means neglected and improperly used high pressure tanks in the presence of stupid people are dangerous. But then anything used by a stupid enough person can become lethal at some point any way.

 

[Diver300]

I'm with tcmtech on this. I also dive, and there haven't been any scuba cylinders explode in years.

When I started diving, the cylinders had to be tested every year and inspected every 6 months, although there was no inspection date stamped on the tanks so it wasn't really enforced, and you could get cylinders filled up to a year after the test.

In spite of the ever increasing 'health and safety' environment, where regulations are being invented and tightened everywhere, scuba cylinders now only have to be tested every 5 years and inspected every 2 1/2 years (although all dates are now stamped and enforced). There is no way that the rules would have been loosened like that if cylinders had been failing catastrophically, or bursting in car accidents.

Another fact about high pressure gas cylinders is that properly designed ones will not explode if they aren't overfilled, even if damaged. With enough damage, they will leak, but not burst. It's like blowing up a balloon. If you only blow it up a bit, and pierce it, it leaks. If you blow it up a lot, and pierce it, it goes bang. A balloon explosion is insignificant, so they are used right up at bursting point. The clever bit about cylinder design is working out at what point they will explode, and running them at a lower pressure that that.

One compressor operator I know had a cylinder fail in front of him. It was badly rusted, and air started to leak out from under the paint. That was all. It leaked, someone opened the valve to let the rest of the air out, and it wasn't used again. It was a real non-event.

 

[tcmtech]

One compressor operator I know had a cylinder fail in front of him. It was badly rusted, and air started to leak out from under the paint. That was all. It leaked, someone opened the valve to let the rest of the air out, and it wasn't used again. It was a real non-event.

Exactly.

I have worked on regular air compressor tanks that developed leaks many times from rusting out. Its not a catastrophic explosion like a balloon. Its just a pinhole that gradually gets bigger and lets the air out faster and faster. I have many times in my life had to do patch work on old air compressor tanks. I drill out the bad places then weld the holes shut and then hydro test them with water to several times their working pressure ratings. I have had a few develop blow out cracks before while being pressure tested but its not a explosive event but just small crack that opens up and lets out the water in a heavy spray.

The high pressure cylinders used for scuba and industrial applications are designed with highly malleable metal so its nearly impossible to get an actual explosive destruction of one. (only in the movies that happens) They can normally be bent, stretched, and crushed severely without leaking. The relief valves are also flow limited so it still takes a little time for a cylinder to vent itself if crushed bad enough.

Badly corroded and stress fatigued metal can fail with large pieces bing ripped out of it but to get to that point unrealistic levels of degradation and abuse had to occur for some time before that. Stress fatigue and corrosion degradation are cumulative effects not an instantaneous effects.

The story I heard about the stupid scuba divers was that the tank taking off like a tethered rocket on the high strength hose being used to fill it is what killed the two or three people next to it. They didn't get ripped to pieces like a bomb went off but instead received fatal impact injuries from being hit by the tank and compressor unit flying around between them.

 

[jrz126]

Well, just an update on this. This may surprise you but the problem was my water pump. It was freezing up and was causing the drive belt to screw up which in turn was messing up my power steering. I guess the engine always running very hot and a battery charge problem should have been a clue. With the new pump, my car starts right up, runs, steers, smooth and cool

It took me awhile to really look into it because it was intermittent, but last week it got real bad.

Man I love this car, to heck with GW.

View attachment 38310

I was thinking it was the water pump or some other accessory. My brother had a ford tarus that wouldnt start. I thought the starter was bad, and after putting a new starter and battery cables on it, I found that the AC compressor was siezed.

Thats a nice Trans AM, whats it have under the hood? It must be nice to be able to drive it year-round. I have a 86 Monte Carlo SS that has to sit in storage for the winter. I built a 400+HP 383 Stroker, so I couldn't afford to drive it year round. I'm happy when I get double-digit miles per gallon.

 

[Mikebits]

Mine has a 5.7 Liter. 350cc engine. I have to put the car on ramps to do just about anything. Changing the spark plugs has my cursing for hours.