What's going on everyone? I'm new to the TBI world as I just added a 91 caprice wagon (L03) to my caprice collection. All the cars I have dealt with have been Lt1s with the exception of this one. It was the 305 but it smokes on start up and burns a quart of oil a month....I been a mechanic for a while so I'm sure it's valve seals or piston rings(blow by). Other than that the engine has about 180k on it and run good.

NOW, i can get my hands on a 5.7 350 out of a roadmaster very easy and cheap....I have read all the 305 to 350 swap threads but i haven't found where this has been covered. I looking at swapping the 305 out of the caprice with a 350 our of a 93 roadmaster esate wagon which had the 350 tbi. Now,

my question is....WHAT DO I NEED? I was thinking it should be a direct swap since the cars are both the same...just maybe use the computer, and ESC from the roadmaster and I'm set?

 

You will want to use the 350's injectors also.

 

Start up smoke is valve seals or valve guides. depending on how bad they are I guess they could burn a quart a month. Thier is a thread on swapping from 305 to 350 in the sticky threads above this one.

 

I think you guys are missing what I'm saying here.....I plan on swapping the entire 350 set up out of the roadmaster and put it in the 91 caprice.....I shouldnt need to worry about the 350 injectors because they are on the 350 engine already....I asking is this a direct swap as far as the harnesses are concerned? they are both B body cars and I thought they should both wire up the same. The only difference is one car is a 305 and the other is a 350.....I want to take the complete 350 and swap it with the 305 thats in my 91. I have read all the threads and the B bodies are not covered in the swap threads. I am asking can i just swap the entire complete engine into the 91 and swap the computers or use my 305 computer with the 350 chip from the 93?

 

Should be able to reuse wiring harness and all plug and play id use the 350 computer and chip

 

B body fir 1989-1992 used a 1228746 ECU. Both LO3 and L05. Just swap the chip.

 

well the car that the 5.7 L05 is in is a 93. 93 I think is the only year that the buick wagons had the L05....i will check and see if they have the same computer and just use the 350 chip.....

 

My response was for CHEV B cars. 89-92. L03 and L05. I will look up Buick now.

Tunercat lists definition files available Pont and Buick and Olds. Oddly enough they list no available 1993 Buick B car nor any L05 period. I suspect if a TBI it is a 1228746.

 

that is odd......Maybe it's because they only came in that year i guess...IDK. Im guessing its the same also...im hoping to get the swap down in like a week or 2...just taking my time and working on it when im off work

 

Ok, the 305 was running so well until 3 days ago. I cleaned up the gunk and sludge out of both heads and oil passages.it still smokes so I'm sure it's the valve seals. Now, it hesitates, stumbles, and backfires out the tbi. Changed the fuel filter and CTS and it ran fine for a week and a half. Now it only does it when it's warmed up. Timing is set correctly, no codes, and it only does it when in drive and warmed up leading me to narrow it down to something that affecting it while in closed loop.

Another thing, once warm and it starts to sputter when you give it gas...if i shut it off or if it dies, it won't start for almost 3 hours or more after. It will turn over but as soon as i give it a little gas while starting it backfires and spits air and flames out of the tbi. It's almost like the engine is trying to seize while starting but when at idle it's smooth. no knock. and no noises.

After a few hours, it starts right up and drive fine until it get warm then the exact thing happens all over again.

 

Well I don't know whats wrong with your 305 but I will tell you it's an easy swap I just did it in my 200 dollar special truck, pretty much swap everything you need to swap over from the 305 to the 350 most of the sensors plug and play a lot of them are the same, the tps sensor might be different you just have to wire it don't rememeber when they switched from flat to round but the wiring is simple just cut the tps plug off and rewire it or get an apdapter orrrr swap injectors and use the 305 tbi unit. the knocks and esc are different, althought I have heard of 350 coming with the 305 one it does work thou, the ecm is a quick swap and the easiest than you don't have to worry about damaging the prom. As for the flexplate if the transmissions are the same they thier no need to change them if they aren't the 305 flexplate works fine. Generally speaking the entire swap takes a weekend if you take your time. The cooling sensors maybe different and the oil pressure sending unit might be. They were different on mine but I was using a 95 motor into an 88 truck.

 

also before I forget the ecm plugged changed close to 95 I don't exactly know when so watch out as well, if you got any questions I can give you the answer probably, also some 02 bungs are in the pipe and some in the manifold so you have to watch out

 

its a direct swap. pickup whole engine with harness and swap in. all computer equipment plugs in seeing as they are in the same platform. im pretty sure i read somewhere on this site that the caprice and f bodys shared the same ecm. you clean all the ports in the throttle body? take the tb off and clean the gunk out of the passages. ud be surprised what builds up in the pvc ports.

 

I would say maybe an 02 sensor, that would affect it in closed loop. And the seizing part sounds like timing, but you stated timing was correct (set at zero) right? maybe a plug wire got flopped? but im sure you checked that. Have you checked your trouble codes?

 

Do you have access to a laptop? If so consider building an ALDL cable or purchase one($50). That will tell you if 02 sensor is functioning as expected. As well as other sensors.

 

Checked for codes again...Nothing. took the dizzy and rotor off...they were trashed...The ICM was rusted also pretty bad. What seemed to have happened was the intake coolant hose rotted at one time and had a small leak that eventually kept hitting the dizzy and ICM. SO while im in there..Im swapping rotor, cap, coil, plugs, wires, TBI rebuild hit, and map sensor as all of these seem to have never been done before on this car. I will let you guys know the outcome.