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Engine swap 2002 Avalanche Z66

Paterach

Full Member
Joined
Dec 7, 2015
Messages
23
Location
San Diego
Hello all,
I am new to your forum, i hope someone can help.

I picked up an Avalanche with a blown engine, I got a junk yard motor and i am having some issues with the new motor, as well as a trani problem.

Ive got soot on the number 4 and 8 cylinders. Engine runs very poorly. low to no power.  The soot is very dusty so I get the sense it fuel related. I have not done a compression check as i need to go get a gauge but I am really hoping its not rings.

What can i do or check besides a compression check at this point? It has new plugs new wires. Old capacitors. The service CEL is say PO300 which multiple misfiring.

Also, my trani has something odd going on. When i stick it in gear, I can feel like a pulse, as thought the trani is out of balance. Is it possible to put the trani in that would cause it to be out of balance?

Thanks in advance.

I did a compression check, I got 170 so it looks good.

But now what?

Thnaks

 
Really need more info to help..

1. What year/size motor did you put in?
2. Was it complete? Intake, wires injectors wiring harness and sensors. Or did you need swap parts from the old motor?
3. Does it have a warranty?

Check the the wires with an Ohm meter.. Stock are about 1000k a foot.
Could be dirty injectors, one or more coils..
Could be fuel pump and/or filter.

Good luck

And welcome the Avalanche ownership and to the club..


 
Thank you
i swapped it with same size. 5.3, i had to use my own accessories AC/Power steering. I used the old coils and put on new wires and plugs. Intake was on the new motor.

Warranty is crap, wont cover me unless i have cracked block or something.

Dirty injectors, are they a pain to clean?

I will keep you all posted

thanks
 
Could have a vacuum leak at he intake manifold, that can cause multiple misfires.. Lots of threads here on it..

I would try a good injector cleaner in the gas first, it can't hurt..

Also if it's missing allot it could make it feel like somethings wrong with the trans. Try to get the misfires sorted out first and then see if you still have issues with the trans..
 
Yes, I am thinking that maybe the intake manifold gasket is giving me a problem. I read that there can be problematic causing vacuum leaks.

Right now it is not drive-able as is, so if I want to clean the injectors I would have to do it manually and not an additive.

I am waiting to get the engine running smooth before worry about the trani.


Thanks Randy
 
Paterach said:
So when i change the intake manifold gasket, do i really need to replace the bolts?

I didn't and it hasn't seemed to be an issue.
 
But you should probably replace the knock sensors. They sit in a well and can rust out so you might want to have those handy or just know you might need to if they are in bad shape.. Lots of info here on changing them out and on youtube..



You can make a homemade injector cleaner using a spray can of injector cleaner and hoses, or using compressed air.. You can find them on youtube also some are good and some are bad just be careful and use common sense..
 
Ok,
so this thing is not going well.

I am still getting the PO300 code for multiple misfires. Engine is not running well at all, too poor to move vehicle.

Here is what i have done. not in any particular order

-Replaced intake gasket
-replaced cracked intake
-New spark plugs
-new wires
-new fuel regulator
-compression test for cylinders i suspected as bad and found compression to be the same for good v bad
-tested coil packs, putting a timing light on each wire and confirmed flashing of timing light. Intensity seemed to be the same.
-Sprayed for intake manifold leaks with starter fluid yielded nothing.
-Tested exhaust with temp guage showing that cylinders 2,8 and 7 dont get hot like the others.
-replaced upstream O2 sensors

I am running out of options :E:, please anyone.  :help:

Thanks


 
Sorry to hear your still having problems

You can try swapping #2 cylinder plug with #4, then the plug wires then the coils and see if any one of these causes the misfire to follow. You can try this on 8 and 7 also, if it moves with any of the swaps you found the problem.

A dirty/bad MAF can cause misfires so make sure it's clean.

When the battery has been disconnected the ECM had to do a idle relearn so it will run rough for a while but it shouldn't cause misfires.

Check fuel pressure...

What year 5.3 did you swap in? The reluctor wheel on the crank where 24 tooth up to 2005 and 58 tooth on 2006 and up. If the 5.3L you put in is 2006 or newer that would be a problem but I don't think it would even run, just a thought..
 
Thanks for your help
THe MAF looked pretty clean, I have a K&N, so is the MAF at the Filter side or is it the little pressure sensor on the back top of the intake manifold (MAP)? Or something somewhere else.

I cant post pictures yet, so I cant show you what i am looking at.

Tomorrow Ill swap out coils and plugs as you suggested

Thanks, Ill keep you posted.


 
The MAF is just off the filter box in the intake duct. The MAP is on the intake manifold.

Good luck, just swap one thing at a time so you can isolate. Plugs and wire are new so nothing should happen but you never know..

Do you now what year the 5.3 is?

 
I think some one mentioned earlier about the injectors, maybe a bad connector or a plugged or bad injector, i think if you weren't getting the correct atomization it may lead to a misfire, droplets of gas instead of a fine mist, i think the best way to clean the injector is buy a spare electrical connector using a nine volt battery to open the injector and use a spray cleaner while out of the vehicle, i think you can hook the injector up placing a cup under it you can observe the spray with the key on. Help me out here guys since I've never actually done this.
 
good point,
I had the rails off and cleaned them with spray, but frankly i dont think i did  a good job.

How insane would I be if took the fuel rails off and tried to start the engine, I could see if all the injectors are working... right?

The atomizer probably doesnt throw that much fuel so...

Is that a really bad idea? Seriously.

What could go wrong?  :p

Someone is thinking :beating:
 
Since it's a new to the truck motor the other thing that might be wrong is the Crank Position Sensor, you might just need to take it to a shop and have them do a re-learn on the ECM to talk to the CPS.. Most shops will just charge you time, takes about 5-10 minutes. Last time I had it done it cost $15.00..

You just have to get it there..
 
honestly, that makes more sense than anything else.

Thanks, I will see what it takes to get it there.

so its called a re-learn for the ECM?

 
Yes, just tell them you need to do "Crank Position Sensor relearn", you can usually drive it. If you have a shop close by they just have to hook up their Tech II tool or what ever their diagnostic tool is and run the relearn procedure.. It syncs the CPS with the ECM..

It usually has to be done anytime you put in a new CPS, which you did (new to the truck) or new/reprogrammed EMC.

I had to do mine when I put a new ECM with a performance tune from Nelson and I drove it down there..
 
If i put the old CPS sensor, the one that the computer is already set to, will that avoid the relearning?

the dealer wants 120 to do it, which i m ok with doing if I need to.

Thanks
 
It's worth a try IMO
 
Probably won't work but you never know... A smaller shop can do it and may charge less, I would call around..
 
shoot, I have a buddy that works at a chevy dealer as the manager of the maintenance dept. He talked to one of his techs and he told him that I cant have CEL on when we do the relearn. So now i am back with checking why I have multiple misfires. I was hoping the relearn would clear that problem.

He suggested that I may have later motor which uses different fuel injectors. I am thinking of putting the old fuel injectors, in and see what happens.

This thing is sucking up my last brain cell.
:needhug: not really, I just thought the emoticon looked funny



 
Like I said before, what year is the motor you put in?  Kinda difficult now but can you find any numbers on it, or the paper work from where you bought it. That will at least tell you if it's even compatible..
 
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