1999 Chevy Suburban turns off for split second while driving

green

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#1
We had this problem about 6 months ago. While driving down the road, the engine would die for a second and then restart. Then it started getting worse, and a few times I had to put the car into park and restart it. We took it to our mechanic and they spent a long time but couldn't figure out what was causing it. But they probably filled all the liquids and tightened all the screws while they were checking it out because then it stopped happening.
Then yesterday it did it twice. Has anyone ever heard of this happening? What could be the problem?
 
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#2
we love details, so tell as much as you can of vehicle history.

To be clear this is a GAS engine 5.7L ?
maintance, accident, history?
Js the ck eng light on?
When starting vehicle does the CEL come on @3sec then go out?
If applicable is the security light on?
anything we should know- modificatios, REMOTE starter, added alarms?

You state the engine would die then restart- there wass no starter motor used to start, just a stumble?
 
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#3
Could be your gas station, stepdaughter was having that problem, but was getting a misfire code. Caught it once with my fuel pressure tester, was water in the gas. Told her I only had to go to that gas station once. Not only sold ethanol gas only, but occasionally get water with it. Just let her stay stranded for several hours until she finally learned. But it convenient and I have too much to do. Yeah, like play on your computer and watch MTV for hours, told you there is a good gas station only two blocks away.

But its okay if I spend hours on the damn thing checking out the entire electrical and fuel system. Did a web search and found over 3,700 gas stations in my state have water problems. Ironically, the price of gas is the same at all of them. Even our airport had that problem, twice installed new tanks, finally solved it by using above ground tanks.

Since water is heavier than gas, sits at the bottom of the tank, even only a cup of water can be disastrous, and generally is worse after a fillup.
 

green

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#4
kev2 said:
we love details, so tell as much as you can of vehicle history.

To be clear this is a GAS engine 5. 7L ?
maintance, accident, history?
Js the ck eng light on?
When starting vehicle does the CEL come on @3sec then go out?
If applicable is the security light on?
anything we should know- modificatios, REMOTE starter, added alarms?

You state the engine would die then restart- there wass no starter motor used to start, just a stumble?

Just a stumble, less than a second- might not have even noticed it if the radio hadn't been on.
Yes it is a gas engine. We have kept it maintained regularly - oil changes, etc.
The check engine light isn't on and doesn't come on when starting the car. When it dies, everything goes blank, and when it starts up again everything looks normal.
No modifications, no major accidents, but our frame is bent, probably from trying to haul rocks with the truck. We have the lighter weight Suburban, not the one designed for towing.
Thanks for any help you can give me.

NickD said:
Could be your gas station, stepdaughter was having that problem, but was getting a misfire code. Caught it once with my fuel pressure tester, was water in the gas. Told her I only had to go to that gas station once. Not only sold ethanol gas only, but occasionally get water with it. Just let her stay stranded for several hours until she finally learned. But it convenient and I have too much to do. Yeah, like play on your computer and watch MTV for hours, told you there is a good gas station only two blocks away.

But its okay if I spend hours on the damn thing checking out the entire electrical and fuel system. Did a web search and found over 3,700 gas stations in my state have water problems. Ironically, the price of gas is the same at all of them. Even our airport had that problem, twice installed new tanks, finally solved it by using above ground tanks.

Since water is heavier than gas, sits at the bottom of the tank, even only a cup of water can be disastrous, and generally is worse after a fillup.
We suspected water in the gas because the problem went away for so long. However, we always get filled up at the same station. The only thing is that the last time it happened, it got worse not better, but I don't know if it was on the same tank of gas. This time the tank is nearly full.
We always refill before we get down to a quarter of a tank. Last time the problem went away on its own.
I know next to nothing about cars, so correct me if I am wrong: I am assuming the car draws the gas from the bottom of the tank, because that would explain why it would be worse after a fill-up. So does that mean that eventually all the water will be removed without me doing anything?
I can't find anything on the web about watered-down gas in my area. So if we wanted to prove it was water, we would just use a fuel pressure tester? Wouldn't they have done that when we first took it to get repaired?
Do you think it is likely the gas station is doing it on purpose, just once in awhile, or is it coming from the distributor that way? We use an independent station. Probably a lot of gas stations in the area are getting filled up from the same tanker. There hasn't been anything in the local news about bad gas. It is the law here that all gas tanks have to be underground. So I guess ground water could be seeping in somehow.
Thanks for your help.
 

billr

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#5
Do I understand correctly; when the engines dies you lose all electrical power momentarily? The radio, engine, and panel lights/instruments all flicker out? If that is true, then forget about the gas, that won't kill the electrical system. I would start by checking the heavy ground cables/straps between the battery and engine and chassis. Make sure they are tight and the connections are fairly clean of rust or other corrosion. If the check engine light (CEL) doesn't come on for a couple of seconds at engine start-up, then that should be addressed, but is probably not related to the "stumble". First step there would be to get a read of any trouble codes. And, if that CEL isn't working, then you should probably get codes read to see if any are there that would relate to the stumble.
 
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#6
I have had a couple vechicle that would do this and it was the ignition switch contacts. Try wiggling the igniton switch while the keys are in it while it is running and see if anything goes off intermittely. This is usually caused by having too many keys hanging in the switch.

Also had a chev full size van that water leaked down into the fuse box and caused the fuse contacts to not make good contact. Just a thought.
 

green

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#7
The old man said:
I have had a couple vechicle that would do this and it was the ignition switch contacts. Try wiggling the igniton switch while the keys are in it while it is running and see if anything goes off intermittely. This is usually caused by having too many keys hanging in the switch.

Also had a chev full size van that water leaked down into the fuse box and caused the fuse contacts to not make good contact. Just a thought.
I had heard someone say it was bad to have too many keys hanging on your keychain. I am going to remove all my extra keys and see if it happens again. thanks
 

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#8
billr said:
Do I understand correctly; when the engines dies you lose all electrical power momentarily? The radio, engine, and panel lights/instruments all flicker out? If that is true, then forget about the gas, that won't kill the electrical system. I would start by checking the heavy ground cables/straps between the battery and engine and chassis. Make sure they are tight and the connections are fairly clean of rust or other corrosion. If the check engine light (CEL) doesn't come on for a couple of seconds at engine start-up, then that should be addressed, but is probably not related to the "stumble". First step there would be to get a read of any trouble codes. And, if that CEL isn't working, then you should probably get codes read to see if any are there that would relate to the stumble.
Yes, the whole instrument panel goes black.
I'll get those connections checked out. thanks
 

billr

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#9
Has this ever happened at night, so you could tell if the headlamps also winked out? If they don't, then it's more likely it's the ignition switch than a ground. The lighting, head, tail, courtesy, etc. is the only thing that used to be "direct wired" without going through the ignition switch. I don't know about now, with BCMs, but yours being a '99 I suspect the lighting is still independent of the ignition switch.
 
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#10
Missed the part about the IP going black, typically on these GM SUV's ignition switch is mounted on the lower steering column activated by a rod. Not that difficult to remove. Most are a five pole switch meaning there are five different switches in that box. Ones I have seen used bare copper contacts with dried up grease on them and have turned green. But not with envy, but with an insulating copper oxide coating. Snapped together and can be unsnapped for polishing the contacts like a mirror so you can see your smile in the reflection. Lubriplate can be used as a switch lubricant.

The key also functions to lock the steering wheel and gear shift lever, more dried up grease and corrosion, but the symptoms of this is it difficult to turn the key.

Key has five positions, steering and gear lock, unlocked, ignition on, activate all warning lamps to make sure they are working, and start. Ignition switch is adjustable on the column so like in the run position, want to be sure the contacts are centered properly. But using an ohmmeter on any given pole, can move the switch up and down where the ohmmeter shows the contact breaking point, then center it between those two points.

Another synchronized multi-pole bare copper contact switch that can give problems is the neutral safety switch. Besides enabling the starter circuit, carries shift commands to the automatic transmission that result in shifting problems. Coupled with a multitude of brake switches, also bare copper contacts, besides brake lights, cruise control, OD and torque converter lock up enabling. Then even more bare copper contact switches for the power windows and door locks.

Can keep a guy busy.
 
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#13
You mean one of those real complicated technical service bulletins that tells you if your bumper falls off to screw it back on again? :ROFL
 

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#14
The problem has gotten worse, like it did before. Now it dies while you are moving and doesn't restart. You have to glide to a stop and restart the car. It happened on the freeway. The electrical system must be winking out because the clock is resetting. Since the clock is resetting, I would bet the lights would go out too, but I don't know for sure.
After the freeway incident, we were afraid to drive it again, so we took it to a mechanic. The mechanic sends one of his employees home with you in your car so you can get home and then the employee drives the car back to the shop. This time it died on the way home but didn't restart. The employee got out and jiggled the wires connected to the battery and then it restarted.
If it were related to the neutral safety switch, wouldn't this problem only happen when speeding up or slowing down?
Since the shop has had it they haven't gotten it to fail, but they may not be driving it enough to see it, or the jiggling of the battery wires temporarily fixed it. They said it isn't the ignition system or the battery. It seems to me that since it is intermittent that the most likely culprit is within some cable or connection, but this is from someone who knows diddly about cars.
Now we are worried that they won't find it because they didn't last time, and then we are afraid that it will continue to happen and the car won't be safe to drive.
We just spent a fortune fixing the air conditioning on this car, so it will be a real bummer if we have to get rid of it.
 
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#15
Sounds like it might be a loose connection on the battery..They need to take them off and clean them real good and make sure they tighten them good...might be just loose or some corrosion in the terminals....Jim