95 Chevy Lumina APV 3.8 Stalling Problems

[SavInQuil]

Just recently my Van started stalling. It always starts right back up but will then die again. Sometimes it idles for several minutes and revs up fine but keeps abrubtly dieing. Changed filter last night and tested fuel pressure getting 42 psi with engine off and getting 35-36 psi with it running. Removed vacuum line from regulator with running and it jumps up to 42 psi so believe it is not a fuel problem. Also checked AFM and pulled EGR valve and both appear to be clean. Also checked fuel lines and checked for vacuum leaks and even sprayed the intake area with WD 40 and cant seem to find a vacuum leak. Any other suggestions out there? I searched the threads last night and this morning but am at a stand still.

[LMP]

I have often suggested the crank sensor and the ignition module
www.avigex.ca/xport/d1977a.jpg at that age, are just waiting to let you go in the middle of nowhere and have suggested to have one as a spare ...better yet, change the crank sensor and ignition module to be sure and keep the other as a spare....just in case.
Each is around 69$ new on ebay and changing the ignition module is a 5 minute affair ..but you must rent a puller and come with a lot of patience to extract the engine balancer for the crank sensor...and just removing the balancer bolt needs a hefty impact socket and torque bar....a nice shot from a fellow forum member is to brace the torque bar steady somewhere with the socket in place on the center bolt.....and then kick the starter for half a second.....

[ric_moving]

Do stalling occur after full stopping, or right after deceleration? There is a sensor to "starve" the engine during "hard" deceleration, as when the engine slows rapidly, a high vacuum is created in the intake manifold causing liquid gasoline coating the walls of the manifold to vaporize feeding the cylinders with extra gasoline vapor that has to be negated by extra less feeding of gasoline by the fuel injector. If this sensor is stuck after deceleration, the sensor still thinks the car is in the act of decelerating, and the stuck sensor will tell the computer to keep starving the engine by slowing down the fuel injector, even when the car is no longer in deceleration mode. The openings leading to this sensor needs to be cleared out of any accumulated dirt so that it can measure the vacuum accurately. Otherwise, the sensor needs to be checked by mechanic, if stalling occurs right after deceleration.

[SavInQuil]

The van will stall at an idle or when under power. Sometimes it will run for quite a while other times only a few minutes. Have not been able to try changing out the ignition module or crank sensor yet.

[ric_moving]

When you say the car will run for quite a while, do you mean that the car runs for days, weeks, and even months without stalling problems? Like the car will run normally like new for weeks, until a stall happens, and then the car keeps stalling for a period of time, and all of a sudden the car runs normally again for weeks without any stalling?

When a stall happens, and the engine is able to be restarted with the automatic transmission in "Park" but shifting into "Drive" stalls the car. Does turning on the air conditioner when running successfully in "Park" helps to keep the engine to continue running after shifting into "Drive" sometimes?

When the car runs without any stalling for weeks, does a fresh bout of stalling occur after the car is decelerated while driving (stopping for a red light, slowing down for a slow car ahead, slowing to get off the highway ramp, taking the foot off the gas paddle when driving into congestion)?

If so, the MAF (MAP for the 3.1) sensor may need to be checked.

[ric_moving]

There is a poster that had an intermittent problem with a fuel pump. If the fuel tank is kept low often, it is hard on the fuel pump, as it runs hot without much gasoline to cool it. As the tank level goes down, the pump may get overheated and pump poorly.

[SavInQuil]

It usually wont run for more than 20-30 minutes or so at the most before stalling. It always starts right back up but will then stall again.

[ric_moving]

When it runs for 20 to 30 minutes, is that on the road, or just idling without the car moving? If on the road, local road, or highway? Is the temperature normal at the time of stalling after the 20 to 30 minutes (temperature gauge at the middle mark, or at the 3/4 mark near the red mark?) Fuel gauge level (near empty, 1/4, 1/2, 3/4, or full)? After stalling, and starting engine right back up, the second stall occurs immediately after restarting, or after another 20 to 30 minutes?

[ric_moving]

Cars are now controlled by computers and sensors. It is called drive by wire. As a result, there are two general types of stalling problems. One type of stalling is the result of "hardware" problems, which is the old fashion type of stalling. The other type of stalling is the result of "software/sensor" problems, which is a new type of stalling, that can happen even though there is nothing wrong with the car, other than sometime wrong is happening with the computer sensors. Sometimes it is complicated to figure out whether the stalling is caused by old fashion hardware failures, or the stalling is created by the computer/sensor system.

[bbaz]

Greetings,

I have a Olds Silhouette with same 3.8 engine.. Same symptoms as the van listed in this thread

My van stalls sometimes while driving but mostly when stopping at a traffic light or just idle. Had this car at my mech and he was unable to find the problem. While at the mech the check engine light was on and showed a code for O2 sensor problem.. the car got new O2 sensor stalling got worse after that.. then changed, plugs, fuel filter, ignition module, intake gasket,and ignition switch but still has stalling problem.. A few days ago i changed the cam sensor.. Still stalls.. The car is driving better and seems like the stalling might have gotten better but it still stalls. The car doesnt stall as often and has not stalled while driving. When car is connected to scanner shows no codes or codes in history. Please help

Did the person that started this thread solve the issue on there van..

Thanks

[ric_moving]

Intermittent and random stallings right after slowing or stopping can be due to a sticking MAP sensor (on the Olds Cutless Ciera) which is attached to the air filter canister. On my Lumina APV, it is a slightly different sensor with a similar name. This sensor measures air pressure in the engine, so it has a "moving" diaphragm that can "stick" randomly and intermittently when it gets old and dusty. Other parts either work or do not work, so that the stalling either do not happen at all, or the stalling happens almost all of the time. If the stalling fits happen relatively rarely, and the stalling happens right after slowing the car, or slowing the car to a stop like for a red light or to park a car, but only on a fairly rare basis, then this sensor is to be suspected. Once the stalling occurs, it tends to keep stalling for a period of time like a few hours to a day, but usually clears up the next day with the car running PERFECTLY NORMAL, until a few days to a few weeks later another episode of stalling occurs. Sometimes turning on the air conditioner may temporary clear the fit of stalling, as the car computer increases the feeding of fuel when the air conditioner is used. When driving at highway speeds and slowing, this type of stalling sometimes cause the engine to "buck" severely feeling like something has broken loose inside the engine. Because when the engine is slowed, vacuum inside the engine increases causing any liquid gasoline coating the inside surface of the engine intake manifold to vaporize to feed more fuel into the cylinders, the car computer has to decrease fuel injected into the engine by an extra measure to compensate for the extra gasoline vaporizing due to the vacuum created when the car and engine is in the process of being slowed. Once the vacuum is no longer there, the car computer resumes feeding normal amounts of fuel to keep the idling or running without stalling, unless the computer still thinks there is a vacuum there because of a stuck vacuum pressure sensor. A fit of stalling occurs when the computer decrease the feeding of fuel as if the car is being slowed. After a while the vacuum pressure sensor becomes unstuck by itself, and the car will run as if new for days to weeks. I no longer have the Olds Cutless Ciera, which had this type of stalling, after a friend gave me his old Luminar APV, which does not have stalling problems except a stuck-closed thermostat, which was easily replaced, that can cause stalling during starting of the over heated engine.

[ric_moving]

Another characteristic of my Olds Cutless Ciera type of stalling is that during episodes of stalling fits, the car engine will start and idle with the automatic transmission in Park, but will stall out right after shifting into drive. The computer is feeding just enough fuel to keep the engine idling in Park, but not feeding enough fuel to keep the engine running in Drive. Sometimes, turning on the air conditioner when in Park may cause the computer to feed enough extra fuel to keep the engine running shifting into Drive. In this type of stalling of stalling episodes one day, and running perfectly other days, the sensor may self unstick, or after the vibrations caused by working around the engine unstick the sensor or knock some dust loose in the sensor.

[LMP]

Originally Posted by bbaz

...stalls sometimes while driving but mostly when stopping at a traffic light or just idle. ..changed, plugs, fuel filter, ignition module, intake gasket,and ignition switch ..cam sensor.. ..but still has stalling problem..

WEll....crank sensor, a classic. It is just annoying because you have to pull the balancer pulley....there are several threads on that issue on the Transport forum. http://www.automotiveforums.com/vbul...d.php?t=736818

[tinawooley]

SavInQuil,
I know it's been a while since you posted your problem but I am wondering if you were able to resolve it? I have a 95 Chevy Lumina van with the same problems. MAF sensor has been replaced and the TPS sensor has been replaced. We have replaced all vacuum hoses and checked the ignition coil packs. We also checked and cleaned the IAC sensor and cleaned the throttle body. It's having some electrical issues as well, such as the windows are not working at all and the wipers are working when they want to. I'm not sure if this is related to stalling problem or a seperate issue entirely. Were you able to find out what your problem was? Any insight on this issue would be greatly appreciated. Thanks.

[bbaz]

It turned out to be a bad O2 Sensor, that was the first thing we replaced but unfortunately we received a defective part..

The way we tested was to just unplug the O2 sensor and drive the car with the O2 sensor unplugged. The van drove much better. Drove 95% better

Try driving your van with O2 sensor unplugged and see what happens. of course your "Service engine Soon" light will come on as a result of the O2 sensor unplugged.

Good Luck... let me know if this helped