05 Cobalt 2.2 issues....

[rusty ol ranger]

This pile of shit....

I kept it around as a cheap, decent driving beater to fill in when all the other junk is broke.


Anyways...

It devloped an issue where if you got after it (as in, 3/4-full throttle) it would start missing and cutting out...fuel mileage dropped alot (from 32 to like 24-25) and it was about undriveable on anything but flat ground.

I pulled the codes and got an O2 code (downstream), 2 codes relating to the throttle body/actuator, knock sensor, and EVAP code.

The knock sensor code had been tripped before with no affect on driving. As has the O2 and the EVAP.

So i focused on the throttle. By this time the car was running so shitty it was undriveable. It could barely make 25-30mph and forget a hill.

Replaced the throttle body (electronic), no change. Found two broken wires running to the plug, fixed those, and it ran decent as long as you didnt floor it.

Nephew used it to drive to work whlle his envoy was screwed up. After 2 days he called me said it barely made it into the parking lot. I went and picked him up then a couple days later picked the car up and hauled it home.

Got it home and it was back to running somewhat ok...still boggy as hell though.

Pulled codes again...the code relating to the TB itself was gone...but the throttle actuator code was back. Did some research and found this meant the pedal assembly was bad.

Fast forward to yesterday....changed the pedal assembly (most simple but biggest pain in the nuts job ever). Now its back to barely making 30mph again.

Car starts and idles fine, fuel pressure is around 60 (spec is 57-65 from what i found online), i didnt have my scanner to rescan it though.

Plugs, coil pack, ignition module, etc are all pretty new.

Engine is a 2.2 ecotec, auto trans, 225k miles.

Sorry for the stupid long post....but does anyone have any ideas or experience with these turds? The cobalt forums are worthless unless your asking about turbos or suspension mods.

 

[scotts90ranger]

Throttle actuator codes point to the throttle motor not the pedal from my experience, since you changed the throttle body the amperage to the throttle motor isn't likely getting there. In my world on the GM engine computers I program the throttle actuator codes correspond with the desired throttle position and actual throttle position don't match, it'll add power to the throttle motor to get what it's going for only up to a point... I would look at the connector on the throttle, if any of the terminals are loose fit on the pins then the amps can't get to the motor...

GM likes 4 bar fuel systems which is 58psi so you're good there.

MAF systems are picky on vacuum leaks...

I'd probably do a compression test, some of this sounds like a low cylinder but I would have expected misfire codes... the downstream O2 code could point to this too...

What scanner do you have? Watch fuel trims, should be within 10% normally.

If it's ran with a misfire it could have taken out the catalytic converter, that can melt into a wad and plug things up... they run horrible this way and the fuel trims are usually all over the place.

 

[rusty ol ranger]

Throttle actuator codes point to the throttle motor not the pedal from my experience, since you changed the throttle body the amperage to the throttle motor isn't likely getting there. In my world on the GM engine computers I program the throttle actuator codes correspond with the desired throttle position and actual throttle position don't match, it'll add power to the throttle motor to get what it's going for only up to a point... I would look at the connector on the throttle, if any of the terminals are loose fit on the pins then the amps can't get to the motor...

GM likes 4 bar fuel systems which is 58psi so you're good there.

MAF systems are picky on vacuum leaks...

I'd probably do a compression test, some of this sounds like a low cylinder but I would have expected misfire codes... the downstream O2 code could point to this too...

What scanner do you have? Watch fuel trims, should be within 10% normally.

If it's ran with a misfire it could have taken out the catalytic converter, that can melt into a wad and plug things up... they run horrible this way and the fuel trims are usually all over the place.

My scanner can read fuel trims. When i bought it it had a horrid missfire and probably ran god knows how long like that.

I dont think compression...it ran strong before this...and this kinda happened all at once just progressivly got worse.

Ill dig into it further now you gave me some avenues and ill respond back when i get the info

 

[Blmpkn]

Wouldn't have this problem with a lima..

 

[scotts90ranger]

@Blmpkn lol!

Electronic throttle engines take throttle issues very serious as it can go sideways, usually a very reliable system though... don't want to go full Toyota and go WOT for no good reason so they go to a limp mode easy

 

[rusty ol ranger]

Wouldn't have this problem with a lima..

No if it was a lima, in the 6000 miles i put on the car since ive had it ida done 4 timing belts

@Blmpkn lol!

Electronic throttle engines take throttle issues very serious as it can go sideways, usually a very reliable system though... don't want to go full Toyota and go WOT for no good reason so they go to a limp mode easy

I just still dont understand what was wrong with a friggin cable

 

[scotts90ranger]

No if it was a lima, in the 6000 miles i put on the car since ive had it ida done 4 timing belts


I just still dont understand what was wrong with a friggin cable

Politicians are what is wrong with a cable... when you control the throttle response you can control the air/fuel ratio 1% better on transient conditions, fleet fuel economy probably went up .2% I'd guess or something dumb... I understand it but it's still dumb...

 

[rusty ol ranger]

Politicians are what is wrong with a cable... when you control the throttle response you can control the air/fuel ratio 1% better on transient conditions, fleet fuel economy probably went up .2% I'd guess or something dumb... I understand it but it's still dumb...

Figures

 

[Roert42]

I don’t have any experience with drive by wire stuff.
Sounds like an issue either with one of the sensors related to the fuel, upstream o2 sensors, MAF, maybe a vacuum leak.
Or clogged cats.

Downstream o2 sensors would give you driving issues, but they would tell you your cat is messed up,