Running Bad

Need Help, I recently pulled a blown 3.1 out of my 92 Lumina and dropped in a 2.8 from another car I had, it ran fine in the other car but now in the Lumina it has no bottom end power and the warmer it gets the worse ?? I pulled the engine in tact, wiring sensors and all and just plugged it in to the Lumina...any ideas would be appreciated

Did you get the ECM out of the other car? Thats probably your problem if you didnt.

I will try that, is in the right kick panel area right?

I think its behind the glove box, somewhere in that vicinity at least.

I am at a loss, there is a large black box under the right inner fender with 4 plugs on it, I replaced it with the one from the doner car, the car will run (with no bottom end), once it picks up speed it runs fine. it will not start when cold without the aid of starting fluid.
I don't think I found the ECM and theres nothing resembling it under the dash, trust me, it's gutted! Let me know if you have any ideas.

the ecm is by the right inner fender with 4 plugs as you stated.they are big plugs with lots of wires.

Got the ECM changed, no difference, the thing wont start cold without starting fluid. Additionally I noticed that both fans run constantly regardless of the engine temp. Still have the lag off idle but anything above idle seems fine. Check engine light still on...at a loss here
any ideas?????

Go to Farm & Fleet,An auto parts store,or somewhere and get one of those $30 code readers.You need to find out why the check engine light is on.

I'm guessing the ECM is not reading the temperature correctly, setting mixture too lean for the ambient temp at start-up. Could explain the warmed up issues too. Change the coolant temp sensor (the one for the ECM, not the guage/light, there is 2) and intake air charge temp sensor, if it has one, I can't remember on those if they do or not. They might have been damaged during the swap.

P.S. the fans running suggest too that the ECM thinks the engine is abnormally hot. I'm leaning toward coolant temp sensor. Cheap enough to try, common to get damaged during major surgery. Stumbling coming off idle suggests too lean mixture, another possible effect of incorrect temp sensing.

Ok, since I've changed everything else I am going to change the temp sensor this afternoon and see if that helps, cross your fingers!

Changed temp sensors, no change... getting frustrated
is there anything else that would cause these problems????
Won't start cold without starting fluid, has dead spot off idle, both fans run constantly. I am going to get a code reader and see what exactly the code is I'am looking at, hopefully this will shed some light on the subject, remember, this engine ran perfectly in the regal I pulled it out of.

ECM connectors on the 2 cars are different, the pins are not in the same locations on both, had codes for temp, throttle position, inlet air temp. Changed back to the other ECM and now the car will start & run but still has the coolant temp code.....

Did you swap the wiring engine wiring harness along with the motor?

Engine wiring harness yes, however the plugs at the ECM itself have some different pin locations. I think this has something to do with the temp sensor, throttle position sensors sending codes, I think I'm going to have to change the entire underhood wiring from the firewall out.
unless someone thinks an ECM from a 91 2.8 Corsica will plug & play??
Any Thoughts?

well, I tried the old ECM with the 2.8 chip, no better, I think I will have to change the wiring harness... :banghead: