2008 Aveo, 50K on the car, 1.6L engine, 5 speed transmission, NO A/C
I replaced the timing belt, spark plugs, and valve cover gasket (oil in the spark plug wells) just before 50K. I have a 2009 Aveo with the same engine-transmission combination, so I let the 2008 sit for a year but ran the engine several times over that year, and connected a battery maintainer on the 2008.
In Jan 2018 I started driving the 2008 Aveo and noticed the fuel mileage dropped from 36 MPG in the summer time to around 28 MPG in January. This is normal because the cold weather calls for a richer air/fuel mixture, the cold thickens the oil and greases plus the refinery’s increase the amount of Heptanes (vaporizes faster than summer blend gasoline) and heptanes leads to lower MPG. Anyway the Heptane information was from a friend that works at an oil refinery. I know in past years when it was minus 15f the fuel mileage went down to 28MPG so I didn’t think it was abnormal because January was a bone chiller this year with lots of -0F days
I have been driving the 2008 Aveo for 2 months when the check engine light (CEL) came on and the car started bucking when lightly accelerating. I got a P0340 code (camshaft position problem) on my Innova OBD-2 code reader. I replaced the camshaft sprocket position sensor, checked all 3 timing marks to make sure I installed the timing belt kit correctly and drove the car for a couple of days and the code came back. I drove the 2008 Aveo some more and the CEL went off for about day. The CEL came back on a day later, then went off for an hour, then came back on.
If I let off of the throttle when coming up to a traffic light or behind a slower moving car and then accelerate a little, the engine bucks a time or two and then runs OK.
I bought a second new cam sprocket position sensor and another new timing belt but I haven’t installed it yet. Today I removed the top timing belt cover again and all of the timing marks seem to be where they are supposed to be. I bought a camshaft sprocket tool that goes between the cam sprockets for a 1.6L Chevrolet but the metal cam sprocket holding tool halves do not fit between the sprockets so the tool must be for a different 1.6L Chevy engine. When I changed the original belt, the sprockets moved a little and if this tool I bought would have worked and fit, the cam sprockets can’t move while installing the belt. I borrowed a universal cam sprocket holding tool from O’reiily Auto Parts when I replaced the timing belt but it allowed the sprockets to move a little.
The engine seems to have all of the normal power, but bucks when accelerating just a little. It might crank a little longer when starting but I haven’t noticed anything else that is different. I have not done a compression test. I have read the compression should be around 200PSI.
I do have one concern about the timing marks. When I align the cam sprocket timing marks, the crankshaft mark is a little less than 1/16” from being exactly on the timing marks on the crankshaft and the notch at the front of the engine. I was wondering if anyone got a slightly short belt or the idler pulley might have been a fraction of an inch bigger. My thinking is if the belt was just a fraction shorter or the idler pulley was a little bigger, the crankshaft mark would be shy of where they were supposed to be. My first replacement timing belt kit and water pump was Korean. The timing belt I just bought was made by GoodYear. I haven’t installed the second replacement Goodyear belt or the 3rd cam position sensor yet but will be doing that tomorrow or in a few days.
I read a couple of repair blogs where a crankshaft sensor replacement where you had to do a “re-learn” process but I haven’t read that changing the cam sprocket position sensor needed to have a re-learn carried out.
The cam sprocket sensor has a 12V supply wire, a ground wire, and a signal wire. I haven’t measured the 12 volt or ground connections. I understand the signal wire value needs a scope to read the value. I also have not checked the Cam position wires for continuity from the sensor back to the ECM. I found some web pages for a 2011 European Aveo with a 1.2 and a 1.4 engine that have electrical schematic but not for a 2008 Aveo
Anyone have a similar situation and managed to fix it?
Would connecting a scope tell me if the position signal is out of time? I had a Marquett scope when I worked for an auto dealership back in 1985 but things have changed since then.
I was looking at a dongle and an OBD-2 Android app for under $100 but I don’t think it would tell me much more than what my Innove OBD-2 reader would tell me. I am hesitant to spend the $500 to $2,000 for some of the scopes I saw Youtube videos of. The “BlueDriver” OBD-2 has several good write ups but I think it might not tell me that much more than the Innova unit I have.
2008 Aveo bought new, 50K miles, P0340 codes, bucks when lightly accelerating, 1 new cam position sensor, 1 new belt, checked the timing marks two times-off by 1/16” at the crankshaft when the cam sprockets are perfectly aligned, cam sensor wires visually check OK but no other tests. The car sat for 1 year, the engine was run several times, and drove Ok at first, then the CEL came on.
I took the valve cover off and used a bicycle spoke on the top head surface to see where the cam sprocket timing marks were. Both cam sprocket marks align with the top of the head. This is a way to verify the marks. Honda uses this method and it works on 2008 and older Aveos.
I moved the exhaust cam sensor a little towards the front of the car or closer to the center of the exhaust camshaft and now 95% of the bucking is gone. I still get a cam/crankshaft correlation error so I am suspecting there is some correlation relearn procedure needs to be done. No camshaft relearn is talked about in repair manuals but a crankshaft relearn is.