Help needed, engine swap, pesky P0300 code

[clipper]

Hi Aveo friends, I've got a bit of a problem and I just know one of you has an answer. I just put a perfectly running 06 Aveo, 35,000 mile, 1.6 engine and auto trans into a 05 Aveo. Kept the 05 ECM in car, and kept all the sensors on the 06 engine, only change the throttle body. Re-engineered the vac hoses for the throttle body and spliced in the injectors and crank shaft sensor. Engine started right up and still runs perfect. I got the relearn done but as soon as I left the chevy garage the engine light returned, P0300 random miss fire. I've driven it around town and even on the highway at 55 with no ill effects for a week now. Spark plugs burning perfect and exhaust clean, never a spitter or sputter nor hesitation no matter how hard i drive it. And still gets good gas mileage considering it won't shift into high. So what's the problem? PLEASE

[avguy]

The ECM part numbers are not the same for '05 and '06. Non-matching parts would suggest that there is something physically different internally, which goes beyond just a simple firmware version upgrade. Just speculation, since I have no hands-on experience with this swap.

[petrified.rabbit]

It could be physical, it could be coding, it could be different sensor perimeters... the only way to know is either switch the ecu, switch all the sensors, or switch the coding. GM has made it hard to switch between years with drop in used engines. If the ECU part numbers don't match, and options on top of that your going to run into these problems. Along with all the other problems associated with every swap.

[clipper]

One thing I forgot to mention is I clear the code and start the engine and just let it run or even rev it up the light dose not come on until I drive down the block. Once I took it easy and the light did not come on till going up a hill.

I have considered the sensors, been checking each on the internet. Most so far are listed for 02 through 06, except the crankshaft sensor which has a different wire connector but same specs, least I think that's what I read before.

I'm still hoping someone can point me to a specific point and save me the researching every part.

[avguy]

Unfortunately this is currently not a really active DIY forum, particularly when it comes to stuff like engine swaps. There are a few poke-and-hope shade tree guys like me, and even fewer pros, who regularly contribute. You've already heard from one of them (PR) above, and there's another guy who has rebuilt engines - maybe he might have something more to offer if he happens to read this thread. No other active regulars I'm aware of who are familiar with stuff like this. But there have been some knowledgeable contributors in the past who might have posted something related to your issue. Try doing a few keyword searches to see if anything is stashed away in the archives that might help you out.

[petrified.rabbit]

that kind of sounds like a cam or crankshaft sensor issue for advancing time, which the engine can correct by cutting fuel so it would theoretically still run good. But that is just a diagnosis off a sentence. However the p0300 code would not be alone for that, what scanner are you using? is it advanced enough to get specific codes, or do you have a cheaper handheld that only does general codes?

[clipper]

Chevy garage confirmed that was the only code when I took it in for crankshaft relearn. When the check engine light came back on I checked it again with my cheapy code reader. I have done a massive search for reasons for the P0300 code yet engine gives little or no signs. I am in the process of checking every sensor and relay to make sure they all are compatible.

[clipper]

Thanks petrified.rabbit, for your post about the "sounds like a cam or crankshaft sensor issue". I kelp thinking that too but I was thinking I checked the crankshaft sensor for compatibility and just had to redo the connector. But after going out to the car I see that was the oxygen sensor and the engine still has its original crankshaft sensor, which is not compatible. That's what I get for being in a hurry. So first thing Monday I'm off to the parts store

[clipper]

Yea avguy, I knew this wasn't a real active site but since I like the Aveos and a couple of family members own one too I wanted to join just to see and hear about other Aveos. I use to be a Chevy Vega guy and was a loner with that as far as I knew back then. I haven't had a Vega since about 1998, and haven't driven an Aveo since 2010. But I finally got the chance to get one to fix up and it has a lot of little things to fix. And I want to do a few extra things to it and this site should help. Thanks again avguy

[clipper]

I changed the crankshaft sensor to the 05 spec and got the relearn done again, but still get the p0300 code. One of these days I'll get the little **** fixed