Any car guys know anything about Chevy Impalas?

kuntasensei

So two mechanics later, my '05 Impala has new plugs, new wires, new coil packs, a new fuel filter... and still idles rough, is hard to crank, occasionally stalls when sitting still in traffic (unless you turn the fan on, which bumps the idle enough to keep it going apparently), and I got an awesome 15mpg on my last tank of gas. Any ideas, car people?

I don't really expect anyone to have some miraculous answer for me... I just wanted to ****. I guess this is what I get for paying it off 3 weeks ago! :mad:

treitz3

Has the battery died lately or been switched out?

nguyendot

shot calla, 20 inch blades on the ....
oh wait, nevermind.

3800 engine?

silvertuner

could be a number of issues. when fuel pumps get weak that is a common sign for it (and impalas are notorious for this). typically when i had a problem like that it came down to a handful of issues...

1. weak fuel pump, pressure was bleeding off quickly
2. MAF issue or issue with the circuit
3. ignition module was taking a s@#t
4. lower intake gaskets like a mother f*cker lol
five. the need for a new vehicle lol


ive worked on hundreds of those damn impalas, and i hated every last one of them. they are one of the reasons i decided to leave a shop and only do side work, every impala that rolled into that shop came straight to me, and i was ready to quit after the first 200, and the last 200 made me wanna kick puppies

AudioGenics

You might be able to use an OBDII reader scan tool
and see if there are any pending codes that
indicate a problem. A consult with a shop mechanic for the GM specific diagnostics.

cnh

I drive an earlier model, 2002. Haven't replaced a fuel pump yet. But I'm pretty sure the 05s have a different engine in there? My car has also been idling rough of late...so who knows. One known issue for earlier models was the DexCOOL class action suit which also ran me about 800 dollars in engine gasket repairs. It seems that the coolant GM was using slowly ate away at the engine gaskets (because they decided to use a cheaper gasket?). This led to a 150 million dollar (I think class action suit that brought about 400+ dollars back to the owner from GM).

Don't know if that's still at work on the '05s. But that's my experience.

Other problems with Impalas include...periodic failure of the BCM (Body Control Module) that is kind of the electronics brain of the car. About 450 dollars there. Mine went.

And a failure of a Pass Key-Lock (passive theft system) that is caused by the weight of the keys on the ignition cylinder which begins to wear and eventually engages the passive theft system that tells the car to NOT START even when you insert a legitimate key? I had a friend who knows about cars BYPASS this system and I've been fine ever since. Another, potentially, very expensive repair because the entire dashboard has to be removed to get at everything underneath it. A real pain...so go with the BYPASS!

Another problem is faulty coolant display sensor modules that tell you you need coolant even when your reservoir is FULL!

And finally, although I haven't had this one yet. Failure of the wheel-bearings far earlier than they should because of some inferior materials used in some of the bearings?

Oh, and because I live up north. I'm going to be spending about 1000 dollars the next inspection cycle replacing all my fuel-lines--they're ALL rusting out at 110K?

The long and the short, after about 75K the car needed 650-1000 dollars of repair every year!

I get about 16-17mpg in the winter. But I can hit 30mpg on the highway in good weather?

cnh

Vette C6.r

+1 on getting a scanner and reading the codes.

The first off the bat thing that comes to mind is the MAF as well. Try LIGHTLY taping on the unit and see if the idle speed changes. The throttle plates on alot of cars are VERY prone to getting alot of carbon on them. Get a spray specifiacally for intake manifolds as you could take the factory coating off with other sprays. Clean the throttle plate and the throttle body as much as you can.

Is this a cold or hot problem ?? ECU's run off different sensors depending on temps.

Good luck.

mdaudioguy

silvertuner wrote: »

could be a number of issues. when fuel pumps get weak that is a common sign for it (and impalas are notorious for this). typically when i had a problem like that it came down to a handful of issues...

1. weak fuel pump, pressure was bleeding off quickly
2. MAF issue or issue with the circuit
3. ignition module was taking a s@#t
4. lower intake gaskets like a mother f*cker lol
five. the need for a new vehicle lol


ive worked on hundreds of those damn impalas, and i hated every last one of them. they are one of the reasons i decided to leave a shop and only do side work, every impala that rolled into that shop came straight to me, and i was ready to quit after the first 200, and the last 200 made me wanna kick puppies

^^^^Note to self: Don't buy an Impala.

Wow, sorry about your luck, kuntasensei. We ditched my wife's Volvo a couple of months ago, due to similar problems, which only occurred whenever it randomly decided to actually start. A mechanic couldn't find the issue, and this was after replacing the MAF sensor. And, of course, it had also been recently paid off. Finally fixed it by replacing the entire car at once. Cheaper than one piece at a time, I figured...

kuntasensei

silvertuner wrote: »

could be a number of issues. when fuel pumps get weak that is a common sign for it (and impalas are notorious for this). typically when i had a problem like that it came down to a handful of issues...

1. weak fuel pump, pressure was bleeding off quickly
2. MAF issue or issue with the circuit
3. ignition module was taking a s@#t
4. lower intake gaskets like a mother f*cker lol
five. the need for a new vehicle lol


ive worked on hundreds of those damn impalas, and i hated every last one of them. they are one of the reasons i decided to leave a shop and only do side work, every impala that rolled into that shop came straight to me, and i was ready to quit after the first 200, and the last 200 made me wanna kick puppies

It's the '05 with the 3400 in it.

1. Once the fuel filter was replaced, it's getting 48+ lbs of pressure, so not a weak pump issue.
2. Took the MAF sensor off and cleaned it, no difference. Tapping it doesn't change anything though.
3. I replaced all three ignition coil packs myself on Sunday. It's obviously firing stronger now, but still have the idling/cranking issue.
4. Ugh... That sounds expensive.
5. Hell no! I just paid it off 3 weeks ago! (Which is probably the problem. Heh...)

Car has been scanned multiple times. Originally, it was showing "random misfire", which is why plugs and wires were done. Then it was showing misfires on individual cylinders, which is why I did the coil packs. After that and the fuel filter, no new trouble codes have popped up... but it still stalls at idle and is hard to crank. Forward O2 sensor was replaced 3 months ago.

I'm stumped. Only thing left that I can think of is Idle Air Control or Crankshaft Position Sensor. Any other ideas?

treitz3

Post #2.

kuntasensei

By the way, I can't feel too bad about this... I have not done anything other than oil changes and air filters for the past 4 years, and the car has been very reliable thus far.

No, the battery has not died recently. Was replaced about a year ago and checking it with a meter during cranking shows that it's solid.

cnh

silvertuner wrote: »

could be a number of issues. when fuel pumps get weak that is a common sign for it (and impalas are notorious for this). typically when i had a problem like that it came down to a handful of issues...

1. weak fuel pump, pressure was bleeding off quickly
2. MAF issue or issue with the circuit
3. ignition module was taking a s@#t
4. lower intake gaskets like a mother f*cker lol
five. the need for a new vehicle lol


ive worked on hundreds of those damn impalas, and i hated every last one of them. they are one of the reasons i decided to leave a shop and only do side work, every impala that rolled into that shop came straight to me, and i was ready to quit after the first 200, and the last 200 made me wanna kick puppies

And these are the Chevys that are assembled in GM's premier assembly facility in North America--the Canadian one!!

oi vey!

cnh

treitz3

The reason I ask about the battery is that when they changed it, the car's computer may have reset to different parameters than what it was set at before the battery swap. The same symptoms you describe happened to my Chevy truck after the battery died a couple of months back.

When I took it back in, they had to reset the computer/chip back to factory default settings and then adjust it manually to make necessary changes to adjust for the parameters that had changed since the vehicle was purchased. Apparently, the computer "learns" the vehicle and adjusts depending on the drivers habits and changing/aging of the vehicle. It took about a week after that for the truck to start running like it always had but as soon as I left the dealership, 95% of the symptoms had disappeared.

silvertuner

kuntasensei wrote: »

It's the '05 with the 3400 in it.

1. Once the fuel filter was replaced, it's getting 48+ lbs of pressure, so not a weak pump issue.
2. Took the MAF sensor off and cleaned it, no difference. Tapping it doesn't change anything though.
3. I replaced all three ignition coil packs myself on Sunday. It's obviously firing stronger now, but still have the idling/cranking issue.
4. Ugh... That sounds expensive.
5. Hell no! I just paid it off 3 weeks ago! (Which is probably the problem. Heh...)

Car has been scanned multiple times. Originally, it was showing "random misfire", which is why plugs and wires were done. Then it was showing misfires on individual cylinders, which is why I did the coil packs. After that and the fuel filter, no new trouble codes have popped up... but it still stalls at idle and is hard to crank. Forward O2 sensor was replaced 3 months ago.

I'm stumped. Only thing left that I can think of is Idle Air Control or Crankshaft Position Sensor. Any other ideas?

3400? well that changes everything! lol my assumption was the 3800 lol.

im leaning towards fuel pump still, but without scoping it hot, cold, running, off, cycling, etc who is to say?

ive seen plenty of grand ams, aleros, malibus, etc with 3400's with this issue. it could once again be a number of things.

pull off your vacuum line on your fuel pressure regulator and see if its wet inside there. the diaphragms like to eat **** and die on those.

the CKP sensor is another great place to start looking. have a shop do a crank relearn on it if u think it could be an issue.


guys, im sorry, but a scan tool will only tell you so much. you CANNOT diagnose a car with a scantool alone. there is no "what fixes this problem" function available, even from Snap-On!! lol.

im not saying any of the above are your issues or you should take to heart, but thats just a few ideas to help you. between the ckp, fuel pump, bad pcm, vacuum leaks, intake manifold gaskets, lifters, MAF's, TPS's, and a lot of others, there is any number of things wrong.

hooking up and checking out just what the car is doing is your best bet, check proper values on all the sensors.

kuntasensei

I replaced the fuel pressure regulator myself about 5 months back, because the original one sprung a leak. Already checked the vacuum line to it, just in case.

I wasn't thinking fuel pump because the problems are only at cranking and idle. Once you give it gas, it runs like a bat out of hell. But sit still in traffic and the idle drops to next to nothing. And my gas mileage dropping 4mpg in-town makes me think that something is throwing the timing off (which is why I was thinking crankshaft sensor).

Oh... one more thing. When I first cranked it up this afternoon and gave it gas for the first time, it rattled. Not like a metallic rattle... Like rocks in a barrel. Only did it once though. I was worried that the catalytic converter had gone **** up, but a muffler shop told me it checked out okay.

tonyb

Could it be something as stupid as a hole in a vacuum hose ? Been down that road many moons ago.

kuntasensei

Yeah, shop traced all the vacuum hoses and didn't find anything obvious. Guess we'll see. I suppose with all the stuff I've replaced so far, it's gonna run like new if we can figure out the problem! I'm still at less than $400 spent so far, and all on stuff I would have replaced as a matter of maintenance soon anyway, so no great shakes.

silvertuner

kuntasensei wrote: »

I replaced the fuel pressure regulator myself about 5 months back, because the original one sprung a leak. Already checked the vacuum line to it, just in case.

I wasn't thinking fuel pump because the problems are only at cranking and idle. Once you give it gas, it runs like a bat out of hell. But sit still in traffic and the idle drops to next to nothing. And my gas mileage dropping 4mpg in-town makes me think that something is throwing the timing off (which is why I was thinking crankshaft sensor).

Oh... one more thing. When I first cranked it up this afternoon and gave it gas for the first time, it rattled. Not like a metallic rattle... Like rocks in a barrel. Only did it once though. I was worried that the catalytic converter had gone **** up, but a muffler shop told me it checked out okay.

if u think it CANT be the fuel pump, think again. when the windings start to take a dump, it can be barely noticeable. im not saying this IS your problem, let me say that again.

call your favorite shop and ask for the head tech, and ask him if he'd be interested in makin 20 bucks real quick by doin a crank relearn on your impala. its a quick easy task, but i would still watch the fluctuation on the scan tool and maybe even scope it as well just to be sure. there are so many ways to go about this, and i hate to say it, but you dont appear to have the scan tools required to do this at this point.

short of throwing parts at it, i cant say much more of what to check short of what ive mentioned really. take it to a shop and get the checkbook out.

On3s&Z3r0s

kuntasensei wrote: »

Yeah, shop traced all the vacuum hoses and didn't find anything obvious. Guess we'll see. I suppose with all the stuff I've replaced so far, it's gonna run like new if we can figure out the problem! I'm still at less than $400 spent so far, and all on stuff I would have replaced as a matter of maintenance soon anyway, so no great shakes.

Damn, I just dropped $500 on a new run-flat tire and a 15K service for a Toyota Rav4 (my wife's). The (P)Impala sounds like a bargain maintenance-wise! I wonder if ours is one of the Toyota's being recalled (again). ()

silvertuner

howd i forget this one?

off of your cam sensor, wiggle the wires at the base as well as at the connector on the front of the engine where the steel pipe and the bypass hose meet. pull it apart and check for broken/damaged/corroded pins too.

ive had that one a handfull of times, its just not very common, but a quick/easy check.

gdb

Do you have a plastic intake manifold.....is it cracked?

kuntasensei

silvertuner wrote: »

howd i forget this one?

off of your cam sensor, wiggle the wires at the base as well as at the connector on the front of the engine where the steel pipe and the bypass hose meet. pull it apart and check for broken/damaged/corroded pins too.

ive had that one a handfull of times, its just not very common, but a quick/easy check.

Now I just gotta figure out where all that is. Heh... But thanks for the idea!

kawizx9r

Compression test, since you mentioned misfire(s).

Tour2ma

mdaudioguy wrote: »

^^^^Note to self: Don't buy an Impala.

... made after '71...

The 1964 SS convertible is my fav all-time car... 327 4 bbl, 4-spd...

HS bud had one in burgundy red w/ Blk top and interior...

Great ride...

Sorry for the derail... good luck.

kuntasensei

kawizx9r wrote: »

Compression test, since you mentioned misfire(s).

It's not misfiring anymore, so I think I'm good there.

Took it back in and the guy immediately said he was going to take the Idle Air Control out and clean that and the throttle body. Could just be carbon buildup. I'm keeping my fingers crossed, 'cause he's doing that for free.

nguyendot

yeah it's just a solenoid i believe that can get crusty... girlfriends old car had this get suck and the idle would kill at a stop here and there. I sprayed and tapped it out and it resolved the issue.

pitdogg2

kuntasensei wrote: »

Took it back in and the guy immediately said he was going to take the Idle Air Control out and clean that and the throttle body. Could just be carbon buildup. I'm keeping my fingers crossed, 'cause he's doing that for free.

bet it works I have a 03 silverado and just out of the blue one day it just would not idle without keeping my foot in it. Took it to my cousin who is a GMC machanic all day everyday and he broke out the carb cleaner sprayed the throttle body and walla worked like a champ....Then he told me to quit using gas with 10% ethanol never had a problem since.

By the way the next motor you get should be a 3800 there bulletproof 3400 not so much
my .02

kuntasensei

Like I said, I can't complain... I paid $14k for this car and have put very little into it in 4 years. I figure I'm coming out ahead either way.

And do you know how hard it is to find gas without ethanol here? It's killing me! Plus, I hear there's a push for using more ethanol now, which sucks.

kuntasensei

Good news! They cleaned the throttle body and idle air control and the RPMs went up about 200. Mechanic says it should be running perfectly now, but recommended running a bottle of Techron through it now that it's all operating as it should. Should all be solid now. Can't really feel too bad, 'cause everything else that was done was stuff I needed maintenance wise anyway.

So yeah, after all that... one minor thing that needed cleaning. Ain't owning a car a hoot? Heh...

kuntasensei

Yeah, just figured I'd drop an update here. Had the car back for two days, running like a champ... then it pegged the temp gauge out. Took it back in, flushed the Dex-cool, bled the air out of the system, seemed fine. Two days later, same problem, thought it was just air remaining in the system, so they bled it again. Took it back in, still getting air in the system, $510 later, I had a new intake manifold gasket. This morning, it overheated again, bubbles in reservoir. So now my guy is doing the head gasket free of charge because it's the last thing anyone figures it can be.

So they've been super cool about it, despite how many times I've had to take it in... but damn! When these things go, they GO ALL TO HELL! Heh...

gdb

That really sucks, hope it's finally fixed right this time!