1987 Olds w/newer engine--stalls

First a word about this car in general. It is an older Oldsmobile, but had been an excellent car up until about four years ago when the engine just died, cracked through on the top and bottom, apparently when the oil ran dry. It sat in storage for about a year and then got a new engine. It was my parents' car up until this time and they gave it to me. It now has about 250,000 miles on it, maybe 80,000 on the new engine, most of the latter as freeway travel.

I did experience some electrical problems early on and replaced the battery, alternator, and finally the positive battery cable. In the middle of this, the mass airflow sensor went out. Not knowing the reason for the problems that caused at first, I replaced the catalytic converter. I commute to work and put close to 2000 miles on the car every month. I usually change the oil about every two months.

And now it has begun to stall. The problem usually happens after the car has warmed up a bit, but it can be on the freeway, in town, in Drive or Park, accelerating, decelerating, or idle. Sometimes it starts right back up, but about half the time, I have to let it sit for anywhere from five minutes to half and hour to get it back. It seemed like keeping the gas tank full made it more reliable, but now I'm not sure.

My first thought was the MAS again, since when it went out before, the car would try to stall out on the freeway also. So I purchased a code reader, plugged it in, and got code 12: nothing wrong.

Okay, since the computer didn't pick it up, it must be a mechanical problem, eh? So today I replaced the fuel filter and air filter and did the oil change that had come due. It still stalls. I might check the fuel pump next, but what I've read seems to indicate that I would have more problems at hight speed.

Someone mentioned in another thread that it might be a camshaft or crankshaft position sensor. Wouldn't this be something the computer would pick up? I'm about ready to take it to a mechanic, though I really prefer to do my own maintenance.

Once I was out on the road about fifteen miles from civilization and the engine heat started to creep up. I stopped near a closed-down store and opened the hood to find my radiator spewing out fluid from where the seam had come apart. Using a pair of pliers, a screwdriver, and a rock (!) I was able to fix the seam, then filled the radiator with water from a hose outside the store. Amazingly, the car made it back to town with no problems and only a small, slow leak.

It looks like it may have been due to a stripped battery terminal. I replaced the battery and cables and so far have had no problems (crosses fingers).

Final follow-up:

Well, a few days after the last update, the car started to die again. I decided to focus on the crankshaft position sensor and discovered that the description for its failure on other websites exactly matched my own problems! It wasn't very difficult to replace at all and after two weeks of driving has shown no trace of the problem.

A word of caution to anyone trying this: make sure you measure the gap accurately. If you don't, you'll get a lot of misfires.

I Read Your Post. I Have A 1987 "88" I Am Having A Problem That Sounds Similar. Cars Starts Every Day Just Perfect. Drives Smooth, Runs Smooth. About 20 Min. Into The Drive The Engine Will Just Shut Off. Sometimes It Starts Up Again, Sometimes I Have To Sit Anywhere From 10 To 20 Min. Then Wella, It Starts. Then It Might Run Another 10 Min. Sometimes It Good Longer. I Did Find That I Could Prolong The Running Time By Having My A/c On. Just To Test This, The Other Day I Drove Home (15 Min.) Then Left The Car Running With The A/c On Wel Past The Time That It Would Have Shut Off. Still Running. Turn A/c Off, Within 30 Sec. Engine Stalls. I Have Done Fuel Filter, Tune Up, Oil And Filter Change (like Thats Going To Help) Still Have A Problem. I Figured Since It Happens After A While That It Was Heat Related. I Am Interested In What Else You Found. You Say That You Replaced The Crankshaft Sensor? What Is This About The Gap? Is This A Hard Job To Do?
Thank You.

So you've got the exact same model. It sounds like you may have the exact same problem. Mine would run anywhere from 10 to 30 mins. of freeway travel before shutting down. On a one hour commute, I once had it shut off four times before I got home. I never got to try the A/C with this one. The compressor died some time ago and it'll be a while before I get the money or the time/knowledge to fix it. Like you, I tried the fuel filter and even replaced the battery cables and some questionable electrical fittings.

A new crankshaft position sensor cost me about $30. It is located down towards the bottom of the engine behind the pulley for the crankshaft (the largest and lowest pulley for the serpentine belt). You'll need to remove the belt to see it and access it. It is attached to the engine block with a bracket that holds it up about an inch. It has an electrical socket attached. Be sure not to confuse it with the camshaft position sensor, which as I recall is further back. You'll see on the back of the crankshaft pulley that there are several metal "teeth" about three inches long that jut straight out to the side and follow the curve of the pulley. Those teeth pass through a groove in the crankshaft position sensor and tell the engine when to ignite the spark plugs.

Just make sure to disconnect the negative battery cable first and remove the serpentine belt. The bracket is held int place with two bolts. I don't recall their size now. You can reach one of the bolts easily with a socket wrench, but the other is at an odd angle behind the crankshaft pulley and will require a tool that can reach it. I was able to get it with a pair of pliers, but it was difficult. Of course, my toolkit is very basic and you may have better luck.

You'll want to remove the electrical socket at this point. You may find that the teeth of the crankshaft pulley are already in the gap of the current sensor. I rotated the crankshaft carefully until the tooth cleared the gap and I could remove it. There is a little post that sticks up through a hole in the middle of the bracket, so you'll have to work it around a bit to pull it out.

Replacing the sensor was a little tricky at first. I had to get the new one back on that post, which wasn't easy since I couldn't actually see it. Once the bolts were back on, I had to rotate the crankshaft back and check the gap between the sensor and the teeth. I wasn't sure how to do this, so I just gave it enough room for the teeth to make it through easily without brushing the sides. I think it is working fine. In my last post, I mentioned misfires because the car bucks from time to time, but I think now after feeling it out that my transmission might actually need some adjustment. My problem seems to only happen when the car is running at certain speeds. You'd feel misfires when the car was idle.

Anyway, replacing the belt and the battery is all that's left at that point. It's been several weeks now and it's still running great. If you've got the know-how to change a fuel filter (without spraying yourself with gas, that is ;)), this should be no problem.