2006 Aveo LT Automatic Transmission Puzzle

[pepper238]

Hi, everyone, I'm new to the forum and I'm sure the answers I'm looking for are here somewhere but I'm down to crunch time trying to get my car fixed. Recently my serpentine belt disintegrated and I replaced it plus the tensioner pulley, after doing so the car idled roughly but I thought it would smooth out once the car ran for a bit. Took off to run an errand and my CEL began blinking. Naturally this perturbed me and I went to Advanced Auto in town and had the codes read. Came back with Camshaft Sensor, Crankshaft Sensor, several misfire codes, and one about torque that I can't recall.

Today I replaced the Camshaft and Crankshaft Sensors as well as my plugs but now my transmission isn't acting right. I shift early out of first and don't have the right power in my acceleration. There's around 130k miles on the car and I could be slightly low on trans fluid. As well as the lack of power I have to let off the accelerator to force the car to shift when driving at highway speed. I can reach 70 mph but the car won't shift or go into torque lock up before 4k rpms when I should be rolling at 3k rpms or so.

I'm stumped and trying to get the car in ship shape before work on Monday since it's the only vehicle my wife and I have. She's taking the car in the morning to work and I hope she makes it. Any and all help is appreciated!

[avguy]

First off, I'd say it's likely theres's still an engine-related issue instead of a transmission problem. Did the serp belt come apart while the vehicle was running? If so, one of the windmilling sections of the belt might have damaged a connector or the wiring harness. Does the belt appear to have the proper tension now, and spinning straight and true?

Although somewhat unlikely, one other possible thing to consider is the harmonic balancer not being torqued properly during a timing belt change, and being the underlying cause of the serp belt issue (and now affecting the timing). Also, have you scanned for codes after replacing the parts?

[pepper238]

The car was indeed running when the serp belt broke and it wrapped itself around the alternator pulley. To my knowledge the timing belt was never changed by my sister in law who owned the car before us. Also the belt spins nice and straight with proper tension although I wonder if I tightened the pulley too much when I put it on after getting the tensioner in place. I haven't checked the codes due to the CEL being off but I'm going to have them checked today.

[pepper238]

Update: Changed the air filter on the off chance it may work and added maybe a quarter of a quart of transmission fluid to the car. No codes could be pulled from the car but my issue still persists. Would the throttle body cause this issue? Any insight would be great.

[avguy]

I'm assuming the vehicle was running fine before the the serp belt broke, and am looking for possible issues caused by that event. But if that's not the case, please post the full story to avoid wasting time.

The belt wrapping around the alt pulley, along with the sudden codes, makes me wonder about the health of the alt. If it was damaged by the stress of the pulley, then perhaps it's not producing completely good output voltage. I suggest doing a running load test on the battery. Get the baseline running voltage (should be somewhere around 13.6), and then turn things on, on-by-one. Voltage should drop momentarily but then quickly bounce back up to the baseline. Leave everything on as you work your way through them. A good running load test does not completely confirm that the charging system is ok, but it's a good DIY step to start checking it.

[pepper238]

I'll have to do that. Took the car to a mechanic and my third cylinder wasn't firing. Turns out my fuel injector is bad so I'm taking the car home to replace it.

[avguy]

I'll have to do that. Took the car to a mechanic and my third cylinder wasn't firing. Turns out my fuel injector is bad so I'm taking the car home to replace it.

You need to be aware that the ECM can shut injection down to cylinders that don't have good combustion. And that could be caused by a number of things. And I'm not big on coincidence, and am doubtful that the injector decided to fail at the exact same time the serp belt broke.

So, instead of just hanging on a new injector, I recommend that you first stall the engine by pulling the fuel pump fuse. Then disconnect the battery to erase computer memory, and pull plug #3 and see if it has spark while a helper cranks the engine. Once you get the answer to that, you can move on from there to additional diagnosis such as testing the injector wire for voltage.

[pepper238]

Had to delay replacing the injector since O'Reilly's only has one model and it's too tall. Other one won't be here till Tuesday. In the meantime plug 3 has spark or at least it did. Now the car won't start at all. Just attempts to crank. Fuel pump clicks on when I turn the key, but otherwise I don't have any luck and I'm stumped.

[pepper238]

UPDATE: Car had jumped timing due to the previous owner before my sister-in-law replaced the timing belt and left old material in the timing case. This material caught in the timing gear when I attempted to start the car and caused the belt to slip time. Thankfully the valves were not damaged.