2000 Alero stalls at highway speed

[skeeter123]

2000 Alero 3.4L V6 with 120K miles, stalls while driving down Interstate. I bought this car used in 2005 (had 52K miles, seller claimed good maintenance schedule), ran good until recently. ~ one month ago had problem with engine overheating, turned out to be warped coolant reservoir (where cap screws on), so that it wouldn’t hold pressure. New cap didn’t fix it. Had to replace the reservoir itself. In the process, I flushed/drained the coolant system several times, switching from Dexcool to Prestone, replaced the ECT (which wasn’t bad after all), switched to a 180-deg thermostat (temp read a notch below half-scale), and patted myself on the back. Then, about 1 week later, this new problem came up. Forgive the long narrative but I think it may be relevant. I assured my wife the car was A-OK and sent her off on a long trip. She got about 120 miles and called me to say the car stalled, while driving normally on the interstate. I was all over the temp thing, but she said it was just fine (below half-way mark). But when she re-started the car, it seemed OK so she went on. Another 100 miles, dies on Interstate, at 70 mph, engine just stops running. Pull over, wait 1-2 minutes, restarted acted fine. I met her & swapped cars. I got about 100 miles, going 76 mph with cruise control on, engine RPMs drop from 2100 to about 1000 for 3-4 seconds, then zero. Coast off to the side of the road, turn off ignition, try to restart, after 2-3 tries it starts up and everything seems A-OK. Same again at about 70 mile intervals, with or without cruise control, all the way home. The time seems to be important, it’s not how many times you try to restart, just wait a full 1 ½ minutes and it starts right up. At no time did the SES or other fault lights come on. Autozone code reader showed no codes. Also, I got 29 mpg on this trip home, including these stalling incidents. Lots of things must be OK for that to be happening. I did find the short U-shaped vacuum hose on the EGR solenoid (which goes from EGR to the plastic vacuum pipe) looked OK when engine off, but would be all sucked in on itself when the engine was running. I replaced it with a piece of vacuum hose Autozone guy gave me for free. I put some fuel injector cleaner in the tank (on sale, and I’m getting desperate), no noticeable effect. More desperate, I put in a new 195-deg thermostat. Operating temp now reads right at half-scale. But it stalled out after only 30 miles, and again 15 miles after that. But this a.m. I got all the way to work (30 miles) without stalling. I think the higher temp thermostat makes problem happen sooner, or maybe it’s just progressing on its own. Is the 180-deg thermostat a good idea? Does it require PCM re-programmming for lower fan turn-on times? Problem never happens on start up or when cold. Putting it in neutral and trying to re-start while coasting doesn’t work. You have to wait the 1-2 minutes. I read this forum and appreciate the advice. I haven’t done the FPR “suck test” yet but I did pop the vacuum line off the FPR and it didn’t smell/look like any gas was leaking. I cranked it with the vacuum line off, didn’t see/smell any gas. I bought this car intending to let my daughter drive it into the ground, so my maintenance approach wasn’t much more than oil&filter and wait till something really broke before fixing it. Glad I got 68K miles off it, but I’d like to not have to buy a new/used car right now. So, I’ve bought the following parts to install: fuel filter, front O2 sensor, 41-940 plugs, set of new spark plug wires. Any other 100K-mile maintenance items I should replace (that hopefully will solve this prob)? The plug wires are definitely the originals, I suspect plugs and fuel filter are also orig. I don’t know, but suspect its never had the LIM-gasket replaced (I groan when reading about all the probs with these Alero’s) but there doesn’t seem to be any coolant in the oil or vice-versa. Serpentine belt looks OK, may/may not be original. Only other thing is that the horn switch in the steering wheel broke, horn works when locking car, but not when pressing on the steering wheel. There’s a spring-loaded slide mechanism in the steering column (behind the air bag) that got all twisted up, I removed the bent-up contact plate, but its possible that the wire may still be loose up in there. This is my first post, any suggestions are greatly appreciated. I am pretty mechanically inclined, prefer to do what I can myself (time permitting) but need this car to get well and don’t want to have it apart for days or weeks at a time. Thanks.

[skeeter123]

Update:

[skeeter123]

Update: sorry but when I said "U-shaped vacuum hose on EGR" I meant the u-shaped vaccuum hose on the "cannister Purge valve". Also, yesterday on way home made it 25 miles before engine died, then happened two more times before getting all the way home. On way in to work today tried running w/o A/C on, temp gauge only got a little bit over half-way mark, problem happened after 20 miles; raised hood and pretended to do something for ~ 5minutes, then started right up and made it remaining 10 miles to work.

I've been reading more on this forum and becoming an auto-hypochondriac. It's quite possible that all the hub assemblies on this car are original (I'm at 120K miles now). It seems like there is more "road noise" than I remember, coming from the front wheels. Not very loud, but more than usual. While waiting the 5 minutes, I felt the wheels and the two front were noticably hotter than the two rear hubs; the front driver's side noticably hotter than the passenger side. Noise doesn't change when turning left/right. I'm OK with replacing the two front hubs, since they've done their duty and they may pose they're own problem soon, but could a failing hub/sensor cause this engine-dying problem?

I haven't received the parts yet (mail-ordered), but will be able to install new plugs, wires, fuel filter and front O2 sensor this weekend.
Thanks///

[seek_bige]

it is a small chance but it could be the mass air flow sensor. a month ago my car had a rough idle, then a week ago it started dying if i turned the steering wheel and three days ago the car did the same as yours. today it would not stay on past a second when i pulled off the switch on the mass airflow sensor and it would run had a high idle but ran. i think it might be the cai i put on it why mine died. i need to know what type of mod. i need to fit the summit racing one on or the pro m racing one thats on jegs.

[skeeter123]

OK; over the weekend I installed the new plugs (41-940's), wires, O2 sensor and fuel filter. Orig plugs were also 41-940's, looked OK, four were tan/light brown, #4 & #5 were darker brown/black but no liquid oil/gas. Also, when replacing the spark plug wires I noticed that the #4 and #5 contacts on the ignition coils were rusted/corroded, all the others were bright and shiny. First few times starting after these repairs, the engine idle cycled from ~400-1200 rpm; and even quit after cycling like that for about a minute. But, after 3 or 4 short drives, this smoothed out and everything seemed fine again. Then, I went for 20-mile drive and engine stalled as before but this time would not re-start. Had it towed back home; not sure what to do now. I did get three new ignition coils and will install them tonight. I'll borrow the OBD-II code reader from Auotzone tonight, maybe there will actually be a code now that its become un-startable. I'll inspect the MAF sensor, but wouldn't that have already set a code? Some advice would be greatly appreciated. And is going back to the 180-deg thermostart (while I'm under the hood) a good idea? Thanks.

[seek_bige]

mine set off a code but you can never tell with these cars. pull off the wires that are attached to the maf and try to start it if it run but at a high idle its the maf.

[skeeter123]

So, tonight I borrowed the OBD-II code reader; no codes, the "I/M monitor" shows no problems with O2 sensor/heater, catalytic converter, or EGR system. Still wouldn't start. I put in the three new coils and cleaned the ECM module, still won't start. I did the FPR suck test, no gas, holds vacuum, seems OK. I can hear the fuel pump run for 3-4 seconds after turning the key. I pulled off the MAF sensor wires, same deal cranks but won't start. Have never seen the security warning light, but I went ahead and did the 10-minute security reset since I am frustrated and desperate. Still cranks but no start. No codes on code reader. Any suggestions?

[skeeter123]

OK, so yesterday I checked:
- All fuses under hood, driver's and passenger's side fuse blocks - all OK.
- I disconnected the ECT and tried to start, no go.
- Tested IAT sensor, +5V supply OK, resistance at room temp(~90deg) was 2Kohms (about right)
- Checked the TPS, 5V supply was OK, and back-probed it while moving throttle, measured 0.6-4.5 volts per spec.
- Checked +12volt into MAF sensor, its OK. Can't do anything else till engine starts.
- Pulled #2, #4 and #6 plugs, all had good spark, looked clean/dry. Shouldn't they have some unburned gas after all this cranking/no-start? So, I'm hoping that its the fuel pump (any definitive solution would by most welcome now).
- I pressed the Schrader valve on the fuel rail, a little bit of gas squirted out. I bought a fuel pressure gauge and will test fuel pressure tonight. I've seen various numbers for fuel pressure in this forum, "41-47psi" "52-60psi" or "nothing under 55", what is the right value? What level would dictate a fuel pump replacement?

Thanks....

[skeeter123]

So, I'm guessing a big fat "zero" fuel pump pressure would indicate it's time to replace the fuel pump. Seriously, I would have thought that there'd be at least some pressure since I can hear the pump run for 3-4 seconds every time I turn the key on; but the needle doesn't even budge off the zero-line on the el-cheapo fuel pressure gauge I got for $16 at HarborFreight (yes, it came w/Schrader-valve attachment). Neither Autozone nor AdvanceAuto would loan/rent a fuel pressure gauge. "Zero" just doesn't seem possible to me, but I'm no expert. Doesn't the fuel pump run until it gets up to pressure and then stop? Why does it stop after 3-4 seconds if it isn't up to the right pressure? I really do hope that this is it; I'm going to get the fuel pump and replace it this weekend, using procedure posted by BNaylor on this forum (thanks)

[skeeter123]

Yes! I replaced the fuel pump, now have 50 psi w/engine running (cheap gauge works just fine). Fuel pressure doesn't leak down (in fact it seemed to go up after ~ 1 minute, from 50 to 55 psi after shutting engine off). Car ran fine on the way into work this morning, idles steady at ~750rpm. Temp still at half-scale; I may switch back to the 180-deg thermostat but I'm tired of working on cars for now. I will also replace the front wheel hubs/bearings soon; if i can't find a good deal I may do that myself as well. To summarize, I now know a lot more about this Alero/V6, and have new plugs/wires/O2 sensor, IAC, fuel pump&filter.
In retrospect, I should have gone after the fuel pump sooner, but I was biased against buying a high-priced fuel pressure gauge (which I'd use only once); I could hear the dang pump run when i turned the key on; and because I thought that replacing the fuel pump would be a harder job. The $16 fuel gauge worked fine, and dropping the gas tank/replacing the fuel pump really wasn't that hard. Car's up and running just in time for daughter to drive herself to school (which just started today).
Thanks for keeping this forum up; it really helps to gather info on all the sensors, controls, wires and vacuum lines involved with this car.

[sightdev]

Originally Posted by skeeter123

Yes! I replaced the fuel pump, now have 50 psi w/engine running (cheap gauge works just fine). Fuel pressure doesn't leak down (in fact it seemed to go up after ~ 1 minute, from 50 to 55 psi after shutting engine off). Car ran fine on the way into work this morning, idles steady at ~750rpm. Temp still at half-scale; I may switch back to the 180-deg thermostat but I'm tired of working on cars for now. I will also replace the front wheel hubs/bearings soon; if i can't find a good deal I may do that myself as well. To summarize, I now know a lot more about this Alero/V6, and have new plugs/wires/O2 sensor, IAC, fuel pump&filter.
In retrospect, I should have gone after the fuel pump sooner, but I was biased against buying a high-priced fuel pressure gauge (which I'd use only once); I could hear the dang pump run when i turned the key on; and because I thought that replacing the fuel pump would be a harder job. The $16 fuel gauge worked fine, and dropping the gas tank/replacing the fuel pump really wasn't that hard. Car's up and running just in time for daughter to drive herself to school (which just started today).
Thanks for keeping this forum up; it really helps to gather info on all the sensors, controls, wires and vacuum lines involved with this car.

"skeeter123", you are the best. This type of information will "live" on forever on the internet and someone on someday will benefit from your persistent attempt and sharing complete experience. You rock!

[skeeter123]

Epilogue - My daughter's been driving the Alero the most, but on the few times I had it out after all this it just seemed not to have the "zip" it used to; I was even thinking there might be a prob with the transmission, since when you give it some gas, get it to kick down a gear and accelerate, it just didn't accelerate like it used to. But yesterday I finally got around to replacing the fuel pressure regulator ($33 Standard Motor Products PR234 from Amazon, even RockAuto couldn't beat that). When I first turned the key on the fuel pressure went right up to 60 psi, and settled at 57 psi with engine idling. It had been between 47-50 psi with the old regulator. It may be my imagination, but it seems like the "zip" is back and the old regulator was wearing out.

[jeffer123]

skeeter123 thank you for your great post. I have theexact symtoms with my alero. I am going to order a new pump and regulator first thing in the morning. Hopefully this will stop thefear of letting my wife drive it as our truck doesn't get as good fuel eco.