Hey guys, got another question...

Will a 2.8 engine run with a 3.1 computer? (If that makes any sence) I have a 2.8 engine in my 1991 Firebird that originally came with a 3.1 engine. The 3.1 computer is still in the car.

There are a few problems that we are trying to troubleshoot so we can work out the bugs.

Thanks, Firebirdjoe

i'd say it would be a little bit on the rich side

Didn't the 2.8's and 3.1's get different injector sizes? Maybe the downsizing in injectors would compensate for the lack of combustion chamber volume going from the 3.1 to 2.8 stroke....

Also, what about the EGR setup? Does your 2.8 have a vacuum EGR or digital? The 3.1 computer is set up for a digital. And also the 3.1 computer is an SD system, whereas the 2.8's are set up for MAF. If you use a 3.1 manifold and MAP sensor from the 3.1 and eliminate the MAF from the 2.8...you should be ok....

We rewired the EGR so that it works with the computer and the car. Other than that would the injectors be a big problem on why the car isn't running right? I hope not

I think the injectors are only a couple pph different...like maybe 16 lb/hr's compared to 14 lb/hr's. Probably wouldnt be a big problem....with a good air/fuel gauge, new O2 sensor, and an adjustable fuel pressure regulator, I'm sure it could be 'tuned'...you could just tweak the fuel pressure to thin it out if it's running too rich.

i would imagine it would "work"

prolly pretty well too

will it be dead on? no

but it should serve your purposes well

If ya was wise & swapped every 3.1 item onto the 2.8 long block you shouldn't have a single problem with the originl vehicle engine management system. That inludes the original ECM from the original year vehicle.
The original year vehicle was designed (those 3.1 sensors) to operate with that original ECM.
In other words, DON'T put in the 2.8 ECM!
I was told & it make such sense, the later the year ECM, the more information it can process.
BUT it only works correctly with the right combination. That means all the 3.1 sensor stuff should be on your 2.8 long block.
Just like I do to my 2.8->3.4 long block swap boogie.
I take the 3.4 long block, redress it in (my instance 1985) 2.8 sensors. I only upgrade in the 3.4 fuel injectors.
Works perfect with my 1985 ECM and all ORIGINAL 1985 sensors.