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96 sts Complete Loss Of Power- No Codes


ItsAllHype

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It has been a while since I have posted for help but this one has got me. I have a perfect running and maintained 96 STS. For no reason I will come to a light and I will notice it start to very slightly idle rough and I will watch the tach move ever so slightly. But this is when I know I am screwed. Now if I try to take off I have to press the gas very lightly to get moving. People behind me start honking at me because I am moving at half the speed a grandma would take off at. It is not the trans because it will do it in nuetral also. It is like complete loss of power. The car will bog down until I let the gas pedal out. No codes will store. The next day when this first happened I went to take it to the dealer and I could not get it to do it again. Then it did it again today. If I try to press the gas down and take off the car will not go. Please help me with this one anyone.

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Could possibly be either the connection at fuel pump (most likely) or the fuel pump itself. They are known to have shorts at the connection on top of the tank. Which would explain the intermittent problem.

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I have replaced the fuel pressure regulator about two years ago. When it was bad the car would backfire on startup and it would crank alot before it started. If it was lean and shot I would think that it would not run right all the time. I drove the car like a mad man on the way to dealer to try and get it to act up again but it would not. I also have a newer egr valve, pre converter O2 sensor, updated fuel rail, plugs, wires, Vehicle Speed Sensor, Trans Input Sensor, Trans Solinoids, fuel filter. Thanks For A Quick Reply. It could be a pressure regulator, I am looking for any ideas. Would a fuel pump do this, I have heard most of the time they just stop working, is this right?

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Mark Grek, did this tank short happen to your car?

It has'nt happened to me, but if you read up in the archives by doing a search you will see that it does happen quite frequently. And it will not throw any codes.

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Time to hook up a fuel pressure regulator gage to the fuel rail and observe the fuel pressure when the car acts up.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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You read my mind on that one. I don't own one but I think I will very soon. I have never had to use one, I just hope I can rig up some length to it so I can get it inside the car or at least lay it outside my winsheild and tie it to the wipper. With the luck I have been having it will probably start to rain. :D

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Most pressure gages come with a 12" hose which is useless for drivability tests....I had a local hydraulic shop remove the crimp fittings, install a 4-foot length of high pressure fuel injection hose and install new crimp fittings for less than $7. It is now long enough to connect to the fuel rail while the gege is duct-taped to the windshield.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Would a fuel pump do this, I have heard most of the time they just stop working, is this right?

I had my pump go, and it took a while to finally die (4 weeks or so). The car died while decelerating, but it started up perfectly...No other incidents for 2 weeks. Then it stalled again, at idle. It shook and stuttered and finally died. I did get it started (had a moment of hesitation) and was able to drive home. I drove it for another week and then it stalled, and didn't start. Luckily I was near my house when it died. Pushed it into my garage, turned on the ignition and listened for the fuel pump hum....no hum. I replaced the pump myself...only problem was I had the tank 1/2 full...A tank on E would be ideal.

A.J.

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  • 1 month later...

UPDATE, after testing the car for four days it seems I have found the problem. The fuel pressure regulator. Because I had changed it before and the symptoms where different, I didn't think this was the problem, but it was. The first time it went I was getting backfiring in the intake and it was cranking a long time before it started. That time was a leaking diaphram out into the intake hose problem causing it to run rich I guess. But this time it was an intermitent running lean problem. Hope this helps out someone. If it comes back and is not solved I will post again. Keeping my fingers crossed.

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UPDATE, It's back. I replaced the fuel pressure regulator and I didn't have it happen for weeks, so I thought it was fixed. Nope. On the way to work this morning I got to a light and I felt the idle stumble a little and I saw the tach flutter some. Sure enough, as soon as I pressed the gas the car would increase speed very, very , very slowly. It took me a block to get up to 30MPH. I could only increase speed if I pressed the gas ever so lightly. If I gave too much, the pedal would feel the way it would if the car was not running and you hit the gas, no response. After work in the parking lot I hooked up the pressure guage that I had in my trunk and started the car. About 42psi at idle, car running fine. Drove it. Car runs great. I will keep the guage on and wait till it does it again.

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ItsAllHype,

It might sound redimentary, but have you checked the fuel filter?

I had identical problems on another vehicle over the past few weeks. It would not accelerate on some days. If I goosed it, the engine "bogged" out and would spit a little. Some days it would improve somewhat and accelerate better, but two days ago it finally got to where I could not get above 50MPH and it took a mile to do this.

I pulled my hair out checking over the components. Finally, I swallowed hard and took it to the dealer - and good thing - $90 later I had a new fuel filter and was back on the road with full power. My initial guess was a TPS or MAF sensor.

Codes pulled from te OBDC pointed to the oxygen sensors, engine misfire and MAF, but these were caused by the fuel starvation from the clogged filter.

Hope this helps.

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I recently had a bad CAT in a 2002 Chevy Monte Carlo, the engine had no power at all, I tested everything, swapped coils, pulled plugs, changed air and gas filters, no codes, and it was the CAT, and it was replaced under warranty. The dealer thanked me for doing all the work and making their job easy! :blink: The 3.4 V6 engine would not rev above 3000 rpm and when the car labored up a hill or in an entrance ramp it had NO power at all... just a thought

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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If the fuel pressure does not drop, what about a plugged catalytic converter? Doesn't it cause the loss of power as Itsallhype has described?

If it's the CAT, the problem would not go away and then reappear again as described. A quick check is to see if the CAT is getting red hot (as in glowing red) after a drive. Check this at night for best effect.

I have heard of a freak event in an older car where a manifold part came loose inside the tube and would flap over and plug the exhaust gas exit - really tough to find, but I don't think these manifold designs are used in caddys.

This is an intermittent problem that could be fuel or electrical related. The fuel pressure will take a dive if it's a regulator or a filter problem, but it could also do this if the fuel pump is involved. If the pressure stays up when the car acts up, fuel system is OK and it could be a grounding problem on the ICS.

I'd be interested in the diagnosis. Hopefully Itsallhype will post it.

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Oh I didnt see that it was intermittant, I was only tagging on at the end of this thread.

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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I have changed the fuel filter. Until I can see what the fuel gauge reads I am at a stand still. I acually leave early for work now so if it happens I have time to look at the gauge and still make it to work. Luck it is early in the morning and I don't have someone behind me. It sucks because I can't make a right turn if cars are coming because I don't know if it will happen then and I will get nailed by someone. My left turns I try to make them while I am still moving.

Been thinking, could it be something stopping my car from getting air (not fuel) and still not trip a code?

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Ill be damned if this doen't sound like an exhaust restriction. This sounds exactly like the problem I was having with the CAT, the only difference being that your problem is intermittant, like, someone else said, something is obstructing the exhaust.

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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