Stalling 2000 Impala

[tringsrud]

In the past 6-7 months, my 2000 Impala has stalled upwards of 10 times. It has happened at different speeds and driving conditions. The battery light comes on and power steering fails. On two occasions, the car started back up on its own after a couple of seconds. The other times I've had to throw it in Neutral and restart.
I've taken it to the dealer twice and they have not been able to duplicate the problem and declined to speculate on what could be causing the stalling. I've heard that it could be: a loose battery connection, failing crank shaft sensor, failing ignition switch etc.....

Any helpful input would be greatly appreciated.

[BNaylor]

Which engine 3.4 or 3800? It's either ignition or fuel.

But it sounds more like the crank position sensor. Most of the time it does not trigger the SES light or store any odb-ii DTC error code.

Another possibility is fuel pressure so you might check that at the fuel injector rail.

[SpinnerCee]

Could be a lot of things:

I had the CAT fail ('01 LS 3800V6) -- This made the car feel like it was running out of gas under acceleration or any kind of load, but didn't stall -- I also did the runaround (tranny, fuel sys, etc...) until someone decided to test the exhaust system backpressure. This problem started intermittently and became presistent quite quickly, only once or twice did the "Check" [engine] MIL light up, then go out.

If this is your case, you should know that OBD-II cats are lifetime warranted, so the dealer must replace them at no cost to you.

[BNaylor]

Originally Posted by SpinnerCee

If this is your case, you should know that OBD-II cats are lifetime warranted, so the dealer must replace them at no cost to you.

Are you sure about that? For 2001 - 2002 Impalas GM recently extended the CAT convertor emissions warranty to 10 years or 120K miles, whichever comes first due to delivery of flaky CATs. On the 2000 Impala it is 8 years or 80K miles, whichever comes first. If out of this coverage there is no doubt in my mind that the dealer will charge for parts and labor.

[SpinnerCee]

I stand corrected.

Look at those numbers though -- if my '01 Imp keeps acting up like it has been, that will be more than it's lifetime with me -- I'm already owner #3 (@~64Kmi.)...

[BNaylor]

Originally Posted by SpinnerCee

I stand corrected.

Look at those numbers though -- if my '01 Imp keeps acting up like it has been, that will be more than it's lifetime with me -- I'm already owner #3 (@~64Kmi.)...

Don't feel bad. We got rid of our '01 Impala LS after tranny and CAT problems. But on the bright side since you have a 2001 if the CAT fails again it should be covered by that warranty extension GM was nice enough to give. Good luck!

[bermis519]

Originally Posted by SpinnerCee

Could be a lot of things:

I had the CAT fail ('01 LS 3800V6) -- This made the car feel like it was running out of gas under acceleration or any kind of load, but didn't stall -- I also did the runaround (tranny, fuel sys, etc...) until someone decided to test the exhaust system backpressure. This problem started intermittently and became presistent quite quickly, only once or twice did the "Check" [engine] MIL light up, then go out.

If this is your case, you should know that OBD-II cats are lifetime warranted, so the dealer must replace them at no cost to you.

I do not believe the OBD-II cars are lifetime warranted, they are coved under warranty up to 80k or 8 years, whichever comes first. After that you are on your own. Trust me, I know.

[BNaylor]

For cars that are out of the GM CAT emissions warranty and out of the extension of warranty for 2001 - 2002 models, I'd get an aftermarket odb-ii compliant CAT convertor such as a Magnaflow. These are hi-flow so there would be a performance benefit and possibly an increase in mileage. Plus Magnaflow gives a 5 year/50,000 mile warranty on the CAT to boot. Aftermarket CATS are in abundance on EBay ranging from $50 - $100. Mom and pop muffler shops charge around $40.00 for installation. And if you have a 3800 it would be a good time to get the u-bend deleted.

[moriab]

My 2000 Impala started doing the same thing about a month ago. So far I've replaced the battery, fuel filter, and air filter. No change. It seems to stall more often when it is cold outside and/or wet/rainy out. It only stalls occasionally on fair weather days. There are no codes in the computer. If I keep the idle high it will prevent it from stalling. I've taken it to the mechanic 3 times now and it has been in the shop a total of 7 days. Every time it is there he can't get it to stall. Someone suggested spark plugs, but there are times when it goes days without stalling at all.

[SpinnerCee]

Electronics are effected by temperature and moisture -- The idle speed control is an electric motor connected to the throttle baldes that is told by the computer to adjust the throttle opening.

This may be important, but you would have to pay close attention to the tach, and what the idle speed is when things are working well, and then compare that to what the tach does when things are not right -- The problem could be that the crank sensor is sending a bad RPM signal to the ECU, or the idle control motor is sluggish under the conditions you describe -- Noting the coolant temperature would help as well, since it could indicate a bad engine temp sensor telling the ECU that the car is cold (and making the tuning adjustments for warm-up), when the engine is actually warmed up. Also beware, the dash temp guage and the coolant temp sensor may be independent of each other (they use a different sensor) , so a good dash reading does not necessarily mean the ECU is getting the correct info.

Low coolant level or air in the cooling system could cause erroneous readings. The sensor does not read as well [accurately] in air as it does immersed in liquid.

A low buck tuning trick is to use a resistor to replace and "set" the coolant temp sensor to an almost warmed-up value to take advantage of the advanced timing and slightly rich injection duration adjustments made by the ECU to simulate the old carb's choke function.

Some of these types of issues may not illuminate the MIL or cause a code to be saved because the sensors are still functioning, but they are sending false, incorrect signals. Electronics are fun, but difficult to dianose because they have a tendency to become intermittent insted of failing altogether.

One more [somewhat wild] guess -- The lockup torque converter in the tranny -- If this lockup function is not working properly, it will not disengage the lockup when it's suppoed to (under 50mph?), so you would stall upon coming to a stop -- this is also an ECU function, related to the VSS (vehicle speed sensor) directly, and possibly throttle position, RPM, and gear selector position... So they're places to look as well.