Replaced Crank and Cam Sensors: Still Dying

[Smith1000]

My wife's 97 Lesabre will die infrequently. When it happens, she puts it in neutral and it restarts immediately. This has been happening for a long time now, maybe 2 years; however, it could go many months without occurring at all. It first happened on a bumpy section of curved road. It now is happening on a hill (same hill). It does not do it every day, but it will happen in a similar spot. I do not know if there is a bump there, or if the slope has something to do with it.

There are no codes. I am ruling out the crank pos sensor and crank angle sensor. I would think there would be a code. Also, it is not heat related.

I just (today) cleaned and tightened the grounds near the computer and near the battery. I cleaned and tightened the battery cables as well.

I have read there is a buss connection on the driver's side that is problematic and may cause intermittant dying. Does anyone know exactly where this connection is located? I would like to clean it up and make sure all is tight and well grounded, but I do not know where to look for this connection.

Does anyone have any other ideas regarding this problem? There are no codes, so I suspect it is a ground or loose connection that separates due to a bump in the road or the hill. I tend to think it is electrical rather than fuel related (at this point) Thanks.

[maxwedge]

Under the ft l/s carpet just inside the sill plate, a series of white gd wires at a multiple junction, a problem here can kill the fuel pump.

[Smith1000]

Thanks. I now have the sill loose and the wires exposed. I am on the driver's side, looking under the sill where the mass of wires run through. The wires are in a group that is kind of tucked under the sill edge. The entire group or mass of wires is about an inch in diameter. There are only 2 white wires in the entire mass.

There is a series of black wires that join in a black plastic coupler. It has a blue piece of plastic on the end. Could it be that the ground sires are black rather than white in the multiple junction or are the white wires elsewhere. I have jiggled this connector with the engine running and, so far, the engine continues to run. It is kind of wet near the wiring. We had some rain this past week and it seems water is getting in there somehow. Thanks.

[Mickey#1]

Yes, it's actually the black wires. Check the passenger side also.

[Smith1000]

Thanks. Just came back in. I see the black plastic multiple junction (about 3 or 4 inches long). It has about 5 wires going into it that all make contact on the metal piece. I removed the plastic end and slid out the long metal piece which did kill the engine. I sanded it some to clean up the contacts. All-in-all, it looks like it is in fairly good shape. I pieced it back together and tucked it all back up under the sill. It would start with the metal piece out, but would not stay running.

There is a similar buss on the passenger side? I'll take a look on that side too.

[Mickey#1]

When does it stall? Is she going up the hill or down?

[Smith1000]

She's not home at the moment to ask, but I am fairly sure she is going down hill because she says she throws it an neutral and restarts it...like she is coasting still and restarts. I'll check for sure though.

The other spot where it has happened, it is relatively level, but is a sharp curve and the road is bump from breaking which kind of rattles the car.

[Smith1000]

The buss on the right side only has 2 ground wires. If I removed the metal piece, making the ground incomplete, the car stays running. Cleaned off well and put it back together.

I drove it quite a while and it ran fine. We'll just have to see how it does now. Maybe it will improve I am wondering if there are any other critical ground connections or fuse connections that could be causing the problem? If so, I would go ahead and check them out. Thanks.

[Smith1000]

My wife says it dies going down hill when her foot is off the accelerator. She said it will do it sometimes when coasting up to a light, on the level, with her foot off the gas. She said it never dies when she has her foot on the gas accelerating. She said it just quits though when her foot is off the gas. Could that possibly be the throttle position sensor?

[Mickey#1]

I think that makes it less likely to be an electrical problem & more likely just an idling problem. I'd start by removing the IAC & cleaning that & where it seats in the throttle body. Use a sensor safe throttle body cleaner & Q-tip to reach into the throttle body. You might also want to remove the throttle body & give it a good cleaning.

Also check for vacuum leaks. I'm sure the rubber hoses on a 97 are getting hard & brittle.

[Smith1000]

Will do. I'll clean it up in the morning. I have some electrical component cleaner that is sensor safe. I am fairly sure I have some MAF sensor cleaner too. I drove it again this afternoon and it ran just fine. It could be a vacuum leak. I have never looked them over too closely. The car has always run so well, I haven't worried about it much. Thanks.

[Smith1000]

It died again today on the same hill. She said it is a fairly steep grade (downhill). Her foot is off the gas and it quietly dies. She says it is tricky because there are no power brakes and no power steering, etc. She puts it in nuetral and it starts immediately (no hesitation). It is a fairly smooth road but a steep down hill grade. The hill seems to be significant to it dying.

I looked at it again tongiht. I did not find any vacuum leaks. The hoses look fairly good. I cleaned the MAF sensor with MAF sensor cleaner. It was very dirty. I lubricated the linkage real well. The idle seems fairly good. I am thinking it is the slope for some reason that triggers it to die. I drove it around and around tonight and it ran just fine. Any ideas are appreciated.

[Smith1000]

I am thinking maybe a blocked sump in the tank or a baffle out of place. It starts up immediately following. Possibly, a bad fuel pump, or bad fuel pump relay, a bad ground to the fuel pump--if not the idle problem. Something related to the downhill grade.

[polarzak]

I know this was a totally different automobile...no computer, not much of anything, but I had the same problem with a 75 Chevy Vega. (what you say?)
I would be driving along and it would die. This would only happen at highway speeds. Sit on the side of the road for a minute or two and it would start right up. My problem was a blocked vent in the fuel cap. I guess this created a small vacuum in the tank when the car need fuel the most. Replaced that gas cap and problem disappeared.


Again, totally different car, (if you can call that thing a car) and different era. Perhaps a code would be generated if this happens in newer vehicle, but I though I would mention it.

[Smith1000]

I remember riding in a Vega once. Didn't Vegas blow up when rear ended? It's funny you should mention the gas cap problem because I read something about a vacuum in the tank causing this situation just last night. I will research that further and check out the gas cap. I don't see how you ever figured out it was the gas cap causing the problem. My sister had some fuel problem with a VW Beetle. She drove VWs for years. It would vapor lock and we had to suck gas out of the tank with a hose and prime the carb. Problem was it was hard to do this without getting gas in the mouth.

My wife said her Lesabre did not die today. She said she just kept her foot on the brake all of the way down the hill so it wouldn't die. I asked her if she really thought that helped. She said it only seems to die when she has her foot on neither the gas or brake when coasting. I doubt there is much to the foot on the brake. Thanks.