97 Riviera Stalls

[GI Bill]

Help, I have a 97 Riviera that stalls without warning at highway speeds, there is no indication of loss to electrical power, temperature and oil pressure appears normal. This problem usually occurs after 20-30 minutes of driving and restarts with no problem. Vehicle runs great and then shuts down any advice would greatly be appreciated.......Thanks

[pcv]

Your crank sensor is the suspect. Let the vehicle run hot and let it stall. If it dosn't stall, with a long pry bar (be careful here as the car is running) wiggle the crank sensor. If it stalls, replace it. If it stalls when running for a while, take a hose and cool the crank sensor down. Start the vehicle. If it starts, replace the crank sensor. There are technical checks for that, that you can go to the library and get all the info.
Good Luck.

[GI Bill]

Originally Posted by pcv

Your crank sensor is the suspect. Let the vehicle run hot and let it stall. If it dosn't stall, with a long pry bar (be careful here as the car is running) wiggle the crank sensor. If it stalls, replace it. If it stalls when running for a while, take a hose and cool the crank sensor down. Start the vehicle. If it starts, replace the crank sensor. There are technical checks for that, that you can go to the library and get all the info.
Good Luck.

Crank sensor checked out fine so I replaced fuel pump which corrected the problem for about 4 weeks and and now I'm back to square one with the same symptoms. I did notice however that the old fuel pump had some evidence of a short because the insulation on a black wire posibly a ground was melted......any clues

[rivirules]

We can say that its most likley fuel or fire. as long as you have good oil pressure (im sure you have checked this right?) I f the fuel pump change corrected this for a while i would say its prob still somthing to do with fuel. did you replace the filter as well? if not try that. you could have some junk in the tank. there are several possab. start checking all the elec. connections, Is the service light coming on? If so it has logged codes and that will help. if it has you can go to most any auto part store and the will check it for free. if you to get some codes i will look them up in my master service manuals. any more info on this and i will to my best to help.

[jdorjoe]

I have a '97 Riviera w/supercharger. It stalls. A new fuel pump in August seemed be the fix until last week, on a long road trip, it began stalling again. It was hot and we expected it to be heat related. It stalled first at 70 mph and restarted while still rolling. An hour later it stalled again and restarted but stalled more and more frequent until it was stalling every few minutes. We rented a car and left the Riviera at a Buick dealership. In a week at the dealership it never stalled once. The odometer showed they had driven more than 300 miles and they reported letting it idle for several hours.

It was a cold day when I drove the vehicle 300 miles home with no problem. The next day was cold and after sitting 15 hours the car stalled a block from home. It is incredibly frustrating in that it will strand me totally - get to the point of running for only a minute or two and even refusing to start. I have the car towed in and it will start right up and they drive it off the truck.

The only time it stalled at the dealership, the fuel pump failed the pressure/capicity test. After a new fuel pump, the car ran for about 5,000 miles before stalling. Another time the dealer diagnosed it as a bad battery, even though the car would spin over normally. I suspected that this diagnosis was bogus, but after a new battery, the car ran about 3,000 miles before stalling.

I suspect electrical issues. It's as if the fuel pump gets turned off.

I saw this posting and thought I'd add to the woes. If any solutions present themselves I'll let you know. Ideas or solutions from you-all are appreciated.

[RABarrett]

I am hearing several problems resulting in stalling and restarting. There is no mention of stored codes. Both of you might try heating various sensors, including the ECM. Since there is no mention of surging, I doubt that the pump is slowing down or stopping. Typically, a drop in pressure, regardless of the speed results in surging, symptoms of lean mixtures, miss, etc. I have seen problems with the ECM's readings of certain engine parameters, including air flow, and engine speed result in stalling, and misreading of air pressure resulting in no starts. It may be necessary to monitor these parameters during driving, to see if something is going on with the readings. The following will result in sudden stallout: No crank signal, sudden changes in air flow readings, loss of spark, either due to module problems, or ECM issues, loss of voltage or ground to these sensors, the ECM, or modules. Even a sudden fuel pump shutdown will result in gradual pressure loss, resulting in surging, missing, etc. It sounds to me as if the computer is either being confused by something or losing something critical. I suspect the ECM at this point, as typically, the loss or confusion of something necessary results in codes of some kind being set, whether valid or not. Ray

[jdorjoe]

ECM advice is welcome. At present the car is at another dealership in another city. It's been there 10 days. They were finally able to make it stall about 40 miles from the dealer and had to have it towed, etc. So they put a new fuel pump in. They say it will be under warrantee because the last one was only 3 months ago.

This car has had lots of techs and nobody's found a code yet. When it fails there is no hiccup, surge, sputter, missing, - nothing. You won't even know the car is stalled until you press the pedal.

I have to say here, that when the dealer replaced the first pump, it appears they did not replace the filter. After installing the first fuel pump I drove the the car about 5,000 miles before stalling. I stalled in a little town in Nevada with no dealership and coasted into a NAPA. The only part they had that might help me was a fuel filter. I replaced it and checked the old one. The old filter was very difficult to blow through and I cheered up.

But I didn't get out of town before the car stalled again.

Could a badly plugged fuel filter cause the fuel pump to fail intermittently and still continue to operate intermittently after installing a new filter?

thanks

[RABarrett]

When I worked at dealer servicing facilities, I took tools with me on test drives. I intended to get answers if the vehicle had the audacity to strand me somewhere. If the customer's complaint was a dying intermittently complaint, I also had a scanner which allowed me to constantly monitor the vehicles computer system. This allowed me to also freeze the last 15 seconds before a problem, and ten seconds after a problem occurred, allowing me to scan, frame by frame, the vehicles operating system. Slowly scanning back and forth, I would ALWAYS see something leading me to the source of the problem. It appears that, in your case, the tech did not do this, allowing the mystery to continue. Sensors such as the throttle position sensor (tps), O2 sensor, EGR etc, typically will lead to soft symptoms, like surging, poor throttle response, etc. Electronic problems, such as the ECM, crank sensors, air flow meters typically lead to drop outs, stalling etc since they will confuse the computer into making fuel and spark calculation errors. I have seen, more than once, the ECM itself be the cause of the problem. Though it is replaced inappropriately due to the ineptitude of the tech, that does not mean that it is faultless. I have replaced the ECM frequently, knowing that the source of the problem was "in the box." Codes are set only when the computer can isolate an incorrect reading. This can lead to confusion for the tech, since the computer's assumption is gleened from two methods, both involving comparisons. By comparing readings between other sensors, or from comparisons to given programmed parameters, the computer constantly checks everything before jumping to conclusions. A truly good tech is ashamed to say I don't know. He will try anything to get answers. They are tough to find, but I will help where I can. Ray

[jststrd]

I have 1991 riviera that has the same problem. It shut off suddenly and stranded us on the road. It was towed to a shop and according to them there was a part on the fuel pump which was shorting. they replaced the fuel pump, still stalled, crank sensor, still stalled, ecm, still stalled, coil pack, ingnition module, wires, plugs, still stalls. If you get a solution please let me know. I am posting my problem also


thanks

[jdorjoe]

I picked up the Riviera an hour ago. I have to say that nothing I've driven, since these troubles began, drives as nice as the Riviera. But then, I was bragging on the car at the instant it broke down last time.

This dealer replaced the fuel pump, under warrantee. They swear the fuel pump was toast.

There is a possibility that the dirty fuel filter burned both the 1st and 2nd fuel pumps. A couple of techs seem to agree that it's possible, but pretty unlucky for me.

I've got to try to drive it like it's cured. You'll hear from me if I find out otherwise.

Thanks

[jdorjoe]

Originally Posted by jststrd

I have 1991 riviera that has the same problem. It shut off suddenly and stranded us on the road. It was towed to a shop and according to them there was a part on the fuel pump which was shorting. they replaced the fuel pump, still stalled, crank sensor, still stalled, ecm, still stalled, coil pack, ingnition module, wires, plugs, still stalls. If you get a solution please let me know. I am posting my problem also


thanks

Do you have any suspicion about the ignition switch itself? Or the electronics in the column?

[jststrd]

no problem with the column or ignition switch I don't believe

[RABarrett]

One more thing I have seen; the loss or corruption of the software in the ECM. I have frequently "repaired" a vehicle with the reinputting of software. As is sometimes the case with PC's, it is possible for the system to corrupt the software while using it. Many times I have experienced problems with a computer operating system and been able to either reboot the system or reload the software, and "cure" the system temporarily. I have done the same with a vehicle, but in order to assure at least a miximum fix, I replace the processor, then reloaded the software. GM offers its software to employees through its own system, updating it from time to time. The result is that whenever a vehicle was rebooted, the latest software was uploaded. Though it is of little consolation to the operator, it could be an issue of software being corrupted. Reloading the software may be the solution the dealer is using to "update the system everytime the vehicle is in for service, as is typical of many dealerships. Though the vehicle may only be in for routine servicing, if the driveline is involved, even remotely, many dealerships update software as a matter of routine. I have also seen frequently a manufacturer build a poor ECM to save a few dollars per vehicle, and attempt to cover up the resulting problems with software. The problems with the ECM created many problems that the software could not deal with, causing its share of problems. Such things as clocks running off frequency, or varying their frequency, conflicting commands, or insufficient memory all save money, but will cause the problems you are describing. The temperatire problems could easily be the result of the processor getting hot and becoming unable to "think." These processors were originally mounted in the cabin; they are now mounted in the engine compartment due to packaging issues. The resulting problems with noise, temperature extremes, and vibration require advanced environmental control, which costs money. If the vehicle gets through the warranty period, the manufacturer is off the hook. I do not know for sure that these are the issues facing you folks, but I have dealt with these issues first hand as a driveability tech for Chrysler, Ford, and GM. I understand your frustration and wish I could do more for you than attempt to explain the possibilities. I tis unfortunate that the dealerships are so pitifully uninformed, or oblivious, but that is one reason I do not work for them anymore. I could not deal with their lackadaisical, laisafaire attitude. They did not care and laughed at me for caring. Ray

[GI Bill]

My 97 Riviera problem of stalling seem to clear up for a while , even took it on a long trip with no problem and I thought well good problem solve.....NOT it just started its crap again and I don't have a clue.No codes, no surging , no warnings just a stall and restart. If anyone on the previous post ever get it figured out please let us know thanks

[JohnleeMax]

Possible dirty MAF sensor???