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Discussion Starter #1
I have done a few engine swaps in my life. When my nephew bought his relatively low mileage Cobalt, I didn't his car would be one of them. Well, he isn't exactly gentle on it.

Long story short, he spun a rod bearing. I switched it out hoping that it had been caught in time. No dice. Time for a new engine. I got a 30k mile 2005 Malibu engine to go into his 2006 Cobalt. 2.2L engines.

We work different shifts and he worked on it when I wasn't there. This included removing the wiring harness from the engine.

Essentially, the engine is installed. Everything is as right as far as I can tell. The engine will actually start for a moment and then die but only once. If I reset the computer, it will do the same again.

The codes it gives are mostly throttle body/position codes. The codes are as follows: P0222, P0220, P2135, P2101, P1516, P0641, P060E, B2AAA.

I read these cars have weak harnesses to the throttle body. I can only assume he yanked on wires when he removed it though he denies it. I cleaned all the terminals. I looked at the wires for breaks/cracks. I took the fuse box back apart and checked inside the plugs for breaks/obvious problems. No dice.

I switched the throttle body and any of the sensors out. No dice. I've reset the computer a few times.


Something I did notice is that the throttle body slams closed. Absolutely no give from all the way closed at any time when trying to start. With the power off the valve is easy to move. Live readings of the throttle position with the key on stay at 50% constantly. The throttle body gets hot to the touch - I assume the plate motor is holding pressure on it at all times is heating up the metal around it.

I'm really not sure where to go from here. I told him to take pictures and be gentle with any wiring but teenagers aren't usually that good at following directions. A video tour of the wiring harness on a 2006 Cobalt would be amazing if anyone could help me out. I can take pictures of any place on the engine or make a video too if anyone would be interested in taking a look.

Most of the cables seem to be only capable of going into one socket, so I don't think they are necessarily plugged into the wrong place but who knows?

Any help would be greatly appreciated.
 

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Worst case Ontario you could always put the original engine's tb on the new engine
 

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Discussion Starter #3
I considered that. They both act exactly the same. I've essentially switched out every part at least once with the ones from the other engine. The codes don't change any with the other throttle body.
 

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Hmm. Did you try disconnecting the battery for a bit to let the computer reset itself?
 

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What year Malibu was the donor engine from?
 

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Says 2005
 

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Missed that lol. That should be a direct swap.

---------- Post added at 08:16 AM ---------- Previous post was at 08:06 AM ----------

Which PCM are you using to control the engine, the one from the Cobalt or the one from the Malibu? Pedal position sensors are different between the 05 Malibu and the 06 Cobalt so you have to use the Cobalt throttle body with the Cobalt PCM.
 

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Discussion Starter #9
I'm using the original cobalt PCM and the original cobalt throttle body. I realized that even though it was a 1 year difference and the engine should have been a direct swap that I would need to change some things. The injectors were different for instance. When it didn't start and threw all the codes - I went ahead and took every electrical part from the old engine even if it seemed right and put them on the new one.

I made sure to get the right one because I know how picky new cars are about parts and I had read that this engine was only the same for a few years.

---------- Post added at 11:38 AM ---------- Previous post was at 11:37 AM ----------

We may have got the wiring wrong but I'm not really sure how since it is mostly just plugs that can only go 1 place.

---------- Post added at 11:39 AM ---------- Previous post was at 11:38 AM ----------

The car started and ran perfect before the old engine was removed btw.

---------- Post added at 11:41 AM ---------- Previous post was at 11:39 AM ----------

I know the engine has spark and fuel because if I disconnect the throttle body and hold the valve open slightly it will start and I can get it to stay running, albeit it roughly.
 

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Well 2 of the codes are for pedal sensor. Did you check to see if it was still connected? You could have accidently yanked on the harness maybe. Doesn't act like a blown fuse.
 

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Discussion Starter #11
I thought the same thing and made sure it was still plugged in. No wires were pulled or stretched while pulling the engine out.

The way it is acting, it seems like it is thinking the throttle is wide open and trying to close it independently of the pedal.
 
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