difference between 99 and newer 3400's [Archive] - GrandAmGT.com Forum


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09-05-2007, 07:53 PM
I've searched and read a lot of info here and elsewhere, but I wanted to start a thread about it for some more info and any questions I might run into here soon. From my understanding the EGR vavle is different, intake, and injectors. Is that correct? My question is, can I use all newer stuff in my 99? I read to do this id have to splice into the injector harness and use my old injectors or something. But I'd like to use everything that comes with the newer engine cuz of the lower miles. Any help would be awesome.

Also I realize the pcm would have to be matched also, would I just pull the pcm our from the donor car if the engine is from a grand am?

09-05-2007, 09:21 PM
The actual EGR valve is the same. It's just mounted at a different angle. The upper intake manifold is different, but the only difference in the casting is the spot where the EGR valve bolts to it. And the injectors are a different size and use different connectors. I believe the cam sensor is different too.

You can use any of the newer stuff on your '99 as long is they have the correct accompanying parts. The only thing that would require anything different in the pcm is the injector change. You could use a pcm from a newer car, but it could cause potential headaches since the vin number won't match and the security code will likely be out of sequence with the bcm so it might not start right away. You'd be better off keeping the pcm thats in the car and having it flashed with a newer program after you install the new parts, either at the dealership or get someone with a tuner to do it for you.

09-06-2007, 04:31 PM
Thanks for the quick response. Another question. Would a 3400 from a Montana or other vehicle than a Grand Am bolt right up also?