Long Block replacement question [Archive] - GrandAmGT.com Forum


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06-01-2010, 08:02 PM
What has to be done computer and sensor wise if you replace just the long block? Do you have to "re-set" the computer or anything?

06-01-2010, 08:11 PM
no, but y are u doing this??

06-01-2010, 08:21 PM
I have a re-built 3.4 and another one my in my daughters car with 144K on it, the less I have to worry about the better..........

06-01-2010, 10:04 PM
what about the crank position sensor? It will be different AND almost certainly in a slightly different spot. I dont know for fact im more just asking.

06-02-2010, 06:15 AM
That was what I was wondering to, hence the question, anyone?

06-02-2010, 07:27 AM
i was more or less asking for you. Didnt know if you knew about it. I would think since its totally different that it would need it. I didnt have to when i put my motor back in, but it was the same CPS and i didnt take it off of the timing cover.

had a thought while working.. Take the timing cover off the old 3.4 and put it on the new 3.4. DO NOT mess with your CPS at all other than wiping off the crud and you should be good to go.

06-02-2010, 02:53 PM
the crank position sensor is om the back of all 3400's. itll be in the same spot

06-02-2010, 03:21 PM
well what the hell is on the timing cover then?

06-02-2010, 03:34 PM
There are two crank position sensors. A 7x one on the back of the block that reads a timing ring built onto the crank, and a 24x one that reads the timing ring in the harmonic damper on the front of the engine. The 24x one controls ignition timing below 3000rpm and is the one that gets calibrated by the pcm.

Any time you remove the pulley, completely change the engine, or change the pcm, that signal will not be sync'd and you'll need to have a CASE learn performed. It will run without the CASE learn though and any dealership can do it for you, and some other repair shops if they have the correct diagnostic tool.

Other than that, it's mostly changing over other sensors and accessories from the old engine to the new one.

06-04-2010, 10:20 AM
Awesome, appreciate the information!