The biggest pain in the 3400 swap is the wiring where to find diagrams, computer pin outs, connector pin id... I have found some wiring info i needed on the forums and though searching but it would be nice to have a post that everyone can add what they found worked and did not work for them, with most of the info needed to find or help a guy to wire up his 3400 swap.

What are you going to use to run the engine? Wiring is different depending on how you go with this. You'd have found this exact same answer if you had used the search button.





www.gmscf.com

I have found the best place for wiring schematics is the library. Use the ALL DATA it covers many vehicles. Hope this helps.

Axel

It really doesn't until you plan on telling us what equipment you want to use.





www.gmscf.com

I am running a 3400 computer from an 03 impala that has been programed for a 5 speed. i have the engine harness for the impala and the entire 97 is wired with 2000 cavalier harness (from the tails to through the fire wall)

I am using the stock cav under hood fuse box, abs, the jbody pcm, i do not want to piggy back the j comp and the impala i want to use the impala alone and i am aware the i may need to use a pass lock bypass module, the j c-100 connector i have is a lil different than shawns link he has posted, which i found when i used the search... kardian has some pin outs listed to, but on a couple wires that i checked on my ecu they are not the same either, I am NOT looking for someone to tell me how to do it, just need links to figure it out, i have searched and finding pinouts for the computer 2003 impala 3400 and its engine connector pinouts is near impossable. The c-100 i am guessing changed in 2000 when the j changed the abs module. any help is welcomed and thanks everybody in advance!

Search ebay for a couple of service manuals. They'll have every wiring diagram you can think of.

I got most of mine for $5-15 each. They're worth having around.

So I went to the shop I used to work at and got the mitchell diagrams for the impala and cavy but i can not find a pin out for the c-100 for 2000 anywhere! I looked at the 99 and that is close but there are extra wires and different colors on the 2000 and I am looking at the diagrams and I don't see the wire colors or what they are for! I am sooooooo very close to getting this thing ready just keep having small wiring problems! I used to like wiring problems but this is making me dislike wires all together! I am down to a handful of wires and they are all on that POS connector! And what is with the ton of same colored wires! Pink and grey everywhere!!!!!!! Any help on the connector is awesome! I will play a little more today and then post the ones that kick my A$$! thanks

All the pink wires are power. If you can't come up with a diagram, hook up your battery and hook a test light to the pinks and a ground. Then make note of when they are on (some will be off/run/crank, some will be run/crank, some will be acc/run etc.). Then you need to make sure that your engine wires which need each specific type of power get hooked to the ones they need. For the gray, those should all be sensor reference feeds, but you will want to check the power they get with the multimeter. They should all have 5v. IIRC, there is a gray that goes to something else, and it will have 12v. Again, once you have them marked, go back to the engine wiring diagram to see what needs to be hooked up. Hope this helps.

learn to read your mitchell schematics and you don't need pinouts

the schematic has the pinouts on it and i know this caus ei built a harness using only the mitchell schemtac no pinouts since its been wired for 00+ you don't have to piggy back the PCM the impala PCM will run the 2000 cluster flawlessly

your on the right track but still do some more reasearch

you will see the PCM connector on the side at 1 end its C1 and the other is C2 then theres a little number after each wire thats the pinout follow that wire on it and it shows you where to go and what the pinout is on the other end if you can't do that you wont wire the car properly and will probably end up poping fuses because you over loaded the IGNITION POSITIVE WIRES, little hint on the cav schematic what ever pinks are paired together do that for the new one



JBO since July 30, 2001

I knew how to read the diagram for the computer, i'm not going to say that i know what every thing on it means but i can not figure out the c-100 connector that is what pin outs would be useful for me, i have matched up the leads that matched from the cavy to the impala computer but i would rather not have to trace wires into the car to see what they are for, and i know i wouldnt have to for all of them just the same colored wires thank you

get a mitchell cavalier schematic for the PCM and it will show the wires the go to the C100, or theres another post on this page asking about 3400 wiring you could check that one and see if theres a C100 pin out in it, this is a reason you should check for similar thread cause if you go to that thread you will be surprized only think is you will have a could different wires i know you wont have UART data line and you will have a white wire in yours i think D3 area thats for EVAP



JBO since July 30, 2001

here is where i am at, car starts and runs, but... the speedo with the car running not moving is at 15 mph any suggestions? i checked the purple wire for the data lines from under hood connection to the pcm it is not shorted to any other wires, so... i am not sure where or why the speedo is freaking out, any one got any ideas???

all the gauges sweep at startup like before, it seems to be just the speedo that is freaking out

are you running two computers? are they piggybacked?


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

since the car has 2000+ wiring and cluster and an impala ecm there would be no need to run duals

running just the 2003 impala pcm, 2000 bcm for cav, 5 spd trans, computer is tuned for 3.4 with a 5spd

hmmm odd... something isnt talking to each other right..


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

If I unplug the vss it does not jump up, but no mph at all traced purple and yellow wires and made sure no shorts, wonder if the cruise signal is messing it up????

did it come with the car or did you add it in? I remember reading somewhere.. dont remember if it was for j-body, but it was for gm cars, the cruise control gets a different amount of pulses then the speedo does.. if you added in cruise control maybe you got a wire switched up?


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

it is the original cavalier cruise

do you have a spare VSS?


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

i do have a spare, ya think, hook it up with out installing first to see what it does and then put it in to see if it changes?

hooked it up out of trans and acts normal, gonna try and swap em out

vss worked! yay now only a lil more to drive her! thank you