'04 Aveo Engine Issues

[Konstantine]

Thanks Lucas, the car is with a new mechanic now, I'll tell him to give it a try.

[Konstantine]

Tried your suggestion Lucas, unfortunately it didn't work.
Light starts flashing as soon as I hit 4th-gear speed, and it won't shift higher than 3rd. POS

[aveobforbes]

it sounds to me that your coils went...prob just two because your up to 3rd gear...that'll cause a blinking cel


check into it seriously

[luklyz]

what codes you are geting. Is it just P300 or something else. You have to tell me few thing
1. If the new engine comes as a short block(naked engine just head, block and oil pen) or long block (with everything). (it is very important cuz your misfire can be cause by some thing else like lose injectors, leaking air intake)
2. How is your engine idle. Any misfire, engine shaking or something diff
3. Can you try to clean injectors using sea foam or marvel mystery oil. You never know the history of the engine

good luck

Lucas

[Konstantine]

Lucas: I get P0300 & P1781
Had a mechanic put in an '06 engine with 25,000 kms but with the '04 intake and throttle (due to the difference in drive-by-wire), changed the plugs, had a computer re-learn, tried replacing the ECM, took it to 2 OTHER mechanics, both are stumped as to why this is still happening.
Car sounds perfect while idling & driving, only issue is the no-shift to 4th (and obviously the light)

Stealership claims the compression is off, but both of the other 2 mechanics say that's BS and that the compression is just fine, so that particular Chevy dealer is blacklisted as far as I'm concerned.

Regardless, I've given up on this car. The light doesn't come on until you try to hit 4th gear speeds so I'm going to reset the sensor, drive to a dealer at low speeds and attempt to trade it in.
Never wasting my money on an Aveo again... wasted $2000 on that engine for nothing.

[khan4rtist]

you should have swapped the LSJ in it!! haha

[petrified.rabbit]

sounds like the overdrive circuit in the tranny is bad. not the engine.

[luklyz]

Hi there.
Try to hang in there with me. I know is hard. There are a few conditions for setting P1781 and P300.
I asked you about misfire at idle, you said engine sound good. Check the idle while under a load. Shift in to drive while pressing the brake, press gas pedal very slowly (dont pass the 1/2 throttle) You should be able to fill misfire. The misfire is causing DTC P300
Causes of P300 leaking air intake (cracked or seal) seals of injectors, leaking head gasket (antifreeze), loose injectors connectors (plugs).

Now About DTC P1781.
It is in fact a TCM (Transmission Control Module) fault, but there are conditions that will set the code, as in an interuption in engine speed (depending on the duration and severity of the misfire).

Dealer is telling you the compression is off. He is right in someway. He is using the information from TSB (technical service bulletin) how to fix DTC P1781 and DTC P300.

Hire is the example
* TSB #050601030 -- 1.6L L91 INTERMITTENT MISFIRE COLD DURING DECELERATION OR STEADY STATE HIGHWAY DRIVING AFTER COLD START WITH DTC'S P0300, P0700, P1781 AND/OR U0401 SET (REPLACE VALVES AND VALVE STEM SEALS) *TT UPDATED 11/02/07 *NJ (NHTSA ID #10017820, SEPTEMBER 01 2007)
* TSB #050604003 -- INTERMITTENT ENGINE MISFIRE HESITATION DURING VEHICLE WARM UP. *EH (NHTSA ID #10013476, JANUARY 01 2005)
* TSB #3064 -- SERVICE ENGINE SOON LIGHT ENGINE MISFIRE AND P1781 DIAGNOSTIC TROUBLE CODE. *EH (NHTSA ID #10011589, no date provided)
# TSB #3064 -- SERVICE ENGINE SOON LIGHT AND ROUGH RUNNING WITH DIAGNOSTIC TROUBLE CODES P0700, P1781 AND POSSIBLY A P0300. *TT (NHTSA ID #10009596, JANUARY 01 2004)
# TSB #01575 -- DIAGNOSTIC TROUBLE CODE (DTC) P1781 DIAGNOSTIC IS NOT IN SI YET. POOR FUEL ECONOMY AND/OR HARSH TRANSMISSION SHIFTS. SIT BULLETIN 1413084. *MN (NHTSA ID #10005436, JANUARY 01 2004)
# TSB #3166A -- SERVICE ENGINE SOON LIGHT DUE TO A P0106, P0300 AND/OR P2279. TO INCLUDE THE NEW 2005 PONTIAC WAVE. *TT (NHTSA ID #10010839, no date provided)


In my opinion ( I always can be wrong )the problem is leaking air intake:
- It could be air intake seal. You said the mechanic switch the air intakes. Did he replace the air intake seal?
- he could cracked the air intake when tight the bolts
- he could could moved(turn) the injectors this will cause the injectors seal to leak

What to do
Check your spark plugs for different color. If they look this same is not the head gasket.
check the injectors plugs for loose. Buy the electric connector cleaner spray plug and injector.
Buy a can of brake cleaner or carburetor cleaner. spray it around air intake when the engine is idling and listen the engine reactions. Then tell someone do "idle while under a load" meanwhile you should spray the brake cleaner or carburetor cleaner around air intake and listen the engine reactions. if there is a difference you found the leak.

good luck
Lucas

[mpmohr]

I was initially told it was a tranny problem too. The 1781 code is a general code that came out as a recent announcement from Chevy. I also received the same P0700 and P0300 codes as you. It's a major engine issue. The dealer had to r&r the cylinder head and replaced all the valves, seals & gaskets. Sorry about the bad news. I'd replace the timing belt every 50k miles on the aveo.

[jcstewartjr]

I have an 05 Aveo with the 1.6 engine that had the check engine p300 acceleration/stall problems starting at about 55000 miles. Finally after replacing the plugs, plug wires twice, the catalytic converter(both done at Wallace Chevrolet in Albany Ga) and the coil(done at the Chevrolet dealership in Savannah Ga two months later) the car ran great for the next 25000 miles. Now the same thing is happening again. I suspect the root cause may be the valve seat problem. As I understand it, when the valves dont seat either (1). oil passes into the piston chamber causing plug fouling and misfire letting raw fuel pass out to the catalytic converter or (2) raw fuel passes out the unseaeted exhaust valve directly to the catalytic converter. Either way the raw fuel damages the converter, which to my understanding is already suspect. Seems there is an issue with the converter not getting hot enough to burn off the elements it is designed to causing the washboard to become clogged, it then chokes the engine thus causing your low idle stalls and acceleration problems which seem to get better after it heats up. Anyone have a recomendation on what to say to the dealership to convince them to do the valve job under warranty? Car now has 82000 miles on it, I have an extended 100,000 mile warranty. Also does anyone know if the Fed warranty of 80000 miles for a catalytic converter only applies to the miles on the car total or the miles on the individual part?