Help with 2010 Aveo engine swap

(edit) You can basically skip this first post, thanks for looking. The problem now is that it runs at high RPM, over 3,000, but won't idle and doesn't respond to the throttle normally below 2,500-3,000rpm. (edit)


Hi all, I signed up here hoping to find technical info during my engine swap.

This car isn't mine but I've been doing work on it for a few years for a friend. Two weeks ago the dealer helpfully replaced her water pump for $800 while failing to notice the shot head gasket, now it's in my garage with a 60,000mi engine waiting to be swapped in.

I'm a fairly capable amateur mechanic and this isn't my first time pulling an engine but if anyone has tech specs or gottchas or tips they would be much appreciated.

Off the top of my head right now: Are the flywheel bolts, engine mount bolts and axle flange bolts reusable or torque to yield? Donor engine is an auto, car its going into is a 5spd so I have to transfer the flywheel and clutch over.

Thanks in advance for any help!
-Pellucid

Hello all. There were some delays along the way but the car is not almost running and I'm hoping someone here can point me in the right direction.

I've installed the new (used) engine and everything is hooked, plumbed and filled. Somewhere I'd seen a "learn" procedure for installing a new engine but I haven't been able to find it again. Today I decided that if it will start and idle it's probably smart enough to adapt itself to a different throttle body and sensors. Well... it won't.

After a few cranks it fired up and died out. I'm assuming those first 2-3 cranks were mostly purging air from the fuel rail. Over the next few starts it got slightly better but not enough to run. It still start and go up to about 2,000rpm (sounds smooth) but quickly dies out after a few seconds. If I hold the throttle pedal fully down it will bump along with a lot of misses at 4-500rpm but it doesn't seem to be "learning" anything and so I came back here for some help.

Some info. This car is a 5spd, the donor engine was from an automatic so I had to swap over the original engine harness for the reverse switch and...whatever that other sensor on the 5spd is near the shift linkage.

I think the car had a coil pack update under recall and I'm about to swap coils with the idea that maybe there was an ECU flash that makes it incompatible with the older style coil pack.

Thanks in advance for any help! I really want to get this out of the garage and back in my friend's hands!

I'm torn between not wanting to dump gas into the cat while it's misfiring and wanting to let it run when it will.

It seems like it's the ignition cutting out because I can hear the pump still running just after the engine dies.

did you use the ECM from the donor car or the ECM that was in your friend's car? and does the donor engine look like this:

http://i112.photobucket.com/albums/n...psb1wcmftg.jpg

or this (this is what is SUPPOSED to be in a 2010):

http://i112.photobucket.com/albums/n...psyyng5c8s.jpg

Quote:

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Originally Posted by 2010AveoLT

did you use the ECM from the donor car or the ECM that was in your friend's car?

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Thanks for the reply. It's definitely the later engine ECOTEC type with coil-on-plug ignition.

I'm using the ECM that was already in her car. I got a 60k mile used engine that came pretty complete minus the starter/alternator/PSP. So, the long block, intake and exhaust are from the automatic donor and everything else including the wiring harness is from the car the engine went into.

I'm not trying to keep it running at this point, I'm worried about loading the cat with fuel, but a few times it's run on it's own and it almost seems like it's trying to work. It'll miss and run slow but then start firing normally/more normally and shoot up to about 1500rpm, then drop down to about 1000, back down to 500 or so and then die.

I just swapped over the coil pack and plugs from the dead engine and I'm about to crank it again but the PN is the same on both and the plugs are all the same number so I'm not expecting much.

I've got two loose connectors with no home but I'm pretty positive they are for A/C, which this car doesn't have. A 3 terminal flat plug down under the power steering pump and a 3 terminal plug that is zip tied to the MAF sensor connector. That has the terminals in a pyramid configuration and I think it's for a refrigerant pressure sensor. Unless I'm wrong? I think I'm fresh out of sockets for plugs..

Quote:

---

Originally Posted by pellucid

Hello all. There were some delays along the way but the car is not almost running and I'm hoping someone here can point me in the right direction.

I've installed the new (used) engine and everything is hooked, plumbed and filled. Somewhere I'd seen a "learn" procedure for installing a new engine but I haven't been able to find it again. Today I decided that if it will start and idle it's probably smart enough to adapt itself to a different throttle body and sensors. Well... it won't.

After a few cranks it fired up and died out. I'm assuming those first 2-3 cranks were mostly purging air from the fuel rail. Over the next few starts it got slightly better but not enough to run. It still start and go up to about 2,000rpm (sounds smooth) but quickly dies out after a few seconds. If I hold the throttle pedal fully down it will bump along with a lot of misses at 4-500rpm but it doesn't seem to be "learning" anything and so I came back here for some help.

Some info. This car is a 5spd, the donor engine was from an automatic so I had to swap over the original engine harness for the reverse switch and...whatever that other sensor on the 5spd is near the shift linkage.

I think the car had a coil pack update under recall and I'm about to swap coils with the idea that maybe there was an ECU flash that makes it incompatible with the older style coil pack.

Thanks in advance for any help! I really want to get this out of the garage and back in my friend's hands!

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i had a look in my Digital Factory Service Manual, and found this:

Crankshaft Position System Variation Learn
Note: The crankshaft position (CKP) system variation learn procedure is required when the
following service procedures have been performed, regardless of whether DTC P0315 is set:
Note: The scan tool monitors certain component signals to determine if all the conditions are met
to continue with the CKP system variation learn procedure. The scan tool only displays the
condition that inhibits the procedure. The scan tool monitors the following components:
1. Install a scan tool.
2. Monitor the ECM for DTCs with a scan tool. If other DTCs are set, except DTC P0315, refer to
Diagnostic Trouble Code (DTC) List - Vehicle for the applicable DTC that set.
3. With a scan tool, select the CKP system variation learn procedure and perform the following:
4. The scan tool displays Learn Status: Learned this Ignition. If the scan tool indicates that
DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool
indicates DTC P0315 failed or did not run, refer to DTC P0315. If any other DTCs set, refer to
Diagnostic Trouble Code (DTC) List - Vehicle for the applicable DTC that set.
• Engine replacement
• Engine control module (ECM) replacement
• Crankshaft damper replacement
• Crankshaft replacement
• CKP sensor replacement
• Any engine repairs which disturb the crankshaft to CKP sensor relationship
• CKP sensor activity--If there is a CKP sensor condition, refer to the applicable DTC that set.
• Camshaft position (CMP) signal activity--If there is a CMP signal condition, refer to the
applicable DTC that set.
• Engine coolant temperature (ECT)--If the engine coolant temperature is not warm enough,
idle the engine until the engine coolant temperature reaches the correct temperature.
3.1. Observe the fuel cut-off for the applicable engine.
3.2. Block the drive wheels.
3.3. Set the parking brake.
3.4. Place the vehicle's transmission in Park or Neutral.
3.5. Turn the air conditioning (A/C) OFF.
3.6. Cycle the ignition from OFF to ON.
3.7. Apply and hold the brake pedal for the duration of the procedure.
3.8. Start and idle the engine.
3.9. Accelerate to wide open throttle (WOT). The engine should not accelerate beyond the
calibrated fuel cut-off RPM value noted in step 3.1. Release the throttle immediately if
the value is exceeded.
Note: While the learn procedure is in progress, release the throttle immediately when
the engine starts to decelerate. The engine control is returned to the operator and the
engine responds to throttle position after the learn procedure is complete.

3.10. Release the throttle when fuel cut-off occurs.
4. The scan tool displays Learn Status: Learned this Ignition. If the scan tool indicates that
DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool
indicates DTC P0315 failed or did not run, refer to DTC P0315. If any other DTCs set, refer to
Diagnostic Trouble Code (DTC) List - Vehicle for the applicable DTC that set.
5. Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully.

Thanks for that. I've got the same files I think. Right now no codes are set but it seems like I couldn't do the running part of the process.

In english does that mean you can't replace an engine without a factory scan tool that does Learn modes/adapations? If so...what's the cheapest one?

I've got a decent OBDII scanner but nothing GM specific about it and no Learn modes.

I'm about to call it a night on that car but with the old coil pack and plugs it's running about the same, it cranks then fires and revs to 2500, then drops down to 500ish, back to 2000 then back down to 500 and stalls. I only tried twice and didn't try giving it throttle but it seems marginally better when it is running.

Some more to go on.

So far I've been able to get it through two heat cycles. ambient to operating temp. I found that if I keep playing with the pedal as it's doing it's RPM bounce thing after starting I can catch it and get it up over 3,000rpm. Once it's up there it responds normally to the throttle. I can hold a speed, move it up and down quickly or slowly anywhere from 3-4,500 or so. I didn't rev it much higher but I did come up about 5,500 once.

Once it falls below about 2-2,500 the pedal has little if any input on the RPM, if anything it seems like it wants to die with throttle motion but if I keep it pegged it doesn't really pick up or die more than usual. Jabbing the pedal at just the right time will get it over 3k where the pedal has control again.

To be honest I don't know that much about drive-by-wire throttle. The only wire I really want to see on a throttle is the cable...

I wondered if maybe the automatic and manual shift cars had a different throttle but it doesn't look like they do.

Oh, no DTC's set or pending. Looking at live data I can see the throttle moving but I don't know if that's the pedal or the throttle body.

Found this reddit thread that might have given me something to look at but the reply got deleted. Anyone remember seeing it?

https://www.reddit.com/r/MechanicAdv...lack_of_power/

I've run it through three heat cycles now and it's throwing no active or pending DTC's. I'd try the non-GM scan tool learning procedure but it won't idle. I did try running it at 3,500 for 180 seconds and then shutting it off for 60 seconds but there was no difference in low speed operation.

I'm not really good with DBW throttles, don't like them and never had to troubleshoot one before but I thought maybe I had a bad throttle unit on the new engine based on readings so I hooked up the old throttle and got very similar numbers.

Is there a way to do diagnostics on the pedal assembly?

Here are the numbers I got with the designations from my HF scanner:

Engine Off Values, "new" throttle on engine

TP Closed - 27.2% WOT 39.6%
TP_R - 14.9% / 26.3%
TP_B - 28.6% / 39.6%
APP_D - 19.6% / 85.1%
APP_E - 9.8% / 42.4%
TAC_PCT 19.6% / 37.3%

"old" throttle connected to harness

TP Closed - 27.5% WOT 39.6%
TP_R - 14.5% / 26.3%
TP_B - 28.2% / 40.4%
APP_D - 19.6% / 85.1%
APP_E - 9.8% / 42.4%
TAC_PCT 19.2% / 37.3%

I had thought that maybe the new unit was bad and I'd see more matching values but since they're the almost the same with both units for now I'm assuming they are both good. The car drove to my house under it's own power with only a dying engine and I'm at a loss here. Any help appreciated.

Quote:

---

Originally Posted by pellucid

I've run it through three heat cycles now and it's throwing no active or pending DTC's. I'd try the non-GM scan tool learning procedure but it won't idle. I did try running it at 3,500 for 180 seconds and then shutting it off for 60 seconds but there was no difference in low speed operation.

I'm not really good with DBW throttles, don't like them and never had to troubleshoot one before but I thought maybe I had a bad throttle unit on the new engine based on readings so I hooked up the old throttle and got very similar numbers.

Is there a way to do diagnostics on the pedal assembly?

Here are the numbers I got with the designations from my HF scanner:

Engine Off Values, "new" throttle on engine

TP Closed - 27.2% WOT 39.6%
TP_R - 14.9% / 26.3%
TP_B - 28.6% / 39.6%
APP_D - 19.6% / 85.1%
APP_E - 9.8% / 42.4%
TAC_PCT 19.6% / 37.3%

"old" throttle connected to harness

TP Closed - 27.5% WOT 39.6%
TP_R - 14.5% / 26.3%
TP_B - 28.2% / 40.4%
APP_D - 19.6% / 85.1%
APP_E - 9.8% / 42.4%
TAC_PCT 19.2% / 37.3%

I had thought that maybe the new unit was bad and I'd see more matching values but since they're the almost the same with both units for now I'm assuming they are both good. The car drove to my house under it's own power with only a dying engine and I'm at a loss here. Any help appreciated.

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Let me hook my Cen-Tech 98614 scan tool up to my car in the morning to give you a known good benchmark to work from.

Hey 2010AveoLT, did you get a chance to pull those numbers yet?

And to you know where the AAT, Ambient Air Temp sensor is? I think this one is bad for unplugged because I'm seeing -40 degrees but so far I can't find the thing!

Quote:

---

Originally Posted by pellucid

Hey 2010AveoLT, did you get a chance to pull those numbers yet?

And to you know where the AAT, Ambient Air Temp sensor is? I think this one is bad for unplugged because I'm seeing -40 degrees but so far I can't find the thing!

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the Intake Air Temperature sensor is actually part of the MAF sensor; if one is bad, Both have to be replaced. and I will PM you my Data logging results.

It's not the IAT, it's the AAT. At least according to the scanner. I'm going to go give it one more spin and see if I can get some numbers.


Thanks!

Well... this car is still in my garage. I keep having to go out of town for a week at a time so progress has been slow to none and I'm about to use AAA to have it towed to the only local shop I'd trust.

It all seems to be tied to short term fuel trim. Above 3,000 it's totally* normal, below 3,000rpm it's pegged around +25. That asterisk is for a spike about every 12 seconds where the STFT spikes at high RPM for a single frame and then drop back into negativelow numbers.

Going over this in other forums someone said it sounded like the PCV diaphragm may have gone. While trying a series of things I plugged the PCV inlet in the throttle body and routed the PCV outlet directly into the MAF sensor (pulled out of the airbox) and that didn't help any buy when I taped over the hose and cut a small slit in it, greatly restricting flow, that did help and the car seems to settle into a fairly normal idle.

I thought this was a Eureka moment so I got a new valve cover. In the meantime I drew suction on the hose on the OE valve cover by mouth and was able to feel and hear the diaphragm close. When I replaced the VC I drew a vacuum again and it acted just the same so I think the PCV diaphragm wasn't bad after all.
Replacing the VC did nothing to change the running of the engine. I don't know why it ran better that one time but I haven't been able to recreate it with the same "accessory hose"

No vacuum leaks, the snorkel is good, the PCV pipe is good, checked the intake and everything else with both smoke and MAPP gas for leaks, nada.

Any last ideas before I give up on this thing and send it down the road?

That fuel trim could be an indicator of a vacuum leak. Did you check it with a vacuum gauge, or try spraying some carb cleaner?

Yep, definitely no vacuum leaks. I've been all over it looking for them several times.

The key symptom seems to be something causing the STFT to be way high below 3,000rpm and to blip high every 12 seconds when it's above 3,000.