6th gen 3400 downpipe same as 3800?

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#11

07-19-2015, 05:23 PM

JrDonahue396ss

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Join Date: Jul 2015

Posts: 6

Quote:

Originally Posted by The_Maniac

I don't see why an aftermarket cat can't be welded to the downpipe (that's how the factory one was done). Just make sure the welds are solid and all around, no leaks, should be good.

Treated right, that 3400 can last a LONG time. I know someone pushing a 3400 Grand Am to 300K (he has over 250k on it now and just keeps changing the oil and it keeps going). Those 60* v6's are pretty durable and reliable engines.

Now, the BCM. If you got a replacement BCM, you should really get that properly programmed with a GM Tech II scan tool (that computer contains various information about the options of the car).

As for the PCM relearn process, here it is from the shop book:

Turn ON the ignition, with the engine OFF.
Attempt to start the engine, then release the key to ON (vehicle will not start).
Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
Turn OFF the ignition, and wait 5 seconds.
Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the Passlock™ Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK).

Important: The vehicle learns the Passlock™ Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.

Start the engine (the vehicle has now learned the Passlock™ Sensor Data Code and/or password).
With a scan tool, clear any DTCs if needed (history DTCs will self clear after 100 ignition cycles).

So do I bring the BCM itself in to GM so they can program it or will i have to bring the car in? Also you said the PCM relearn process? Do you mean BCM relearn process? Or is it that the PCM needs to learn the new BCM? I've tried this method just now and it's not starting. Does it matter if I'm even 1 second off? Also when does the 30 minute on period start? When I go from OFF to CRANK or when I go from CRANK to ON (OFF-CRANK-ON)? This is bugging me and I just want to get her Goin lol please any info will help.

#12

07-21-2015, 12:12 AM

The_Maniac

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THe PCM relearn works if you swap a differen PCM into the car or an ignition lock cylinder (which has the PassLock chip on the cylinder, not the ignition switch).
I've never swapped a BCM, so I do not know if that relearn will work with a BCM (again, keep in mind, the BCM also needs programmed for your car and options and can only be done with a TechII, so even if the car starts, you are not done).
The BCM has to be in the car when a TechII is used to program it. I'm sure there are ways to program it without being in the car, but I do not know them.

As for the relearn process, it is vital that you wait long enough for the security light to go out before attempting to turn the ignition off and restart the car. Outside of that, don't take the key out until the car started and I'm pretty sure everything else has wiggle room. That blurb I posted was direct from GM's shop book, direct from GM. I've done it waiting 11-13 minutes in the on position (again, make certain the security message on the message center is not flashing anymore). Before starting this process, ensure you have a fully charged battery and apply the ebrake (which should disable day time running lights).

The 30 minutes is how long it should take, assuming you follow the directions to the letter and it works as planned. I'd plan 45-60 minutes and may need to go through the cycle a total of 3-4 times.

Again, I have no idea how this works with the BCM, if this will work at all. It's a matter of you can try it and see what happens.