Ok I don't need help on the wiring but possibly some insight on how some did it as there isn't much info. How ever I could figure it out if I knew the diagrams. I went to the local dealer to get a few things and to see if they could help me out. How ever they said they can only go back to 05. The 99 sunfire has a 2000 2.4 5speed swap using a 97 harness and computer. Was originally 2200 4 speed auto. I know the differences between the 99 and 97 2.4 so I believe I should be good with any diagram/pinout for the 2.4. I also believe I still have the original 2.2 harness and pcm laying around if I need to swap it back in. For the 3.4 it is out of a 05 grand am gt hooked up to a 2001 2200 tranny. In which I have the full harness, pcm and matching bcm if needed. So is there anyone that could help me out with the diagrams I need? I will be grateful if someone would.

Any way here is somewhat how it sets. Don't mind the top bracket, was just temp to hold the motor for wiring.

either harness will work you need the GA one for sure but you have to merge it 99 should have the evap in the back so i think its D3 should have a white wire if i remember (main plug C100) i personally would switch the dash harness to a 00+ because you have the PCM needed and the wiring is basicly the same work it just allows you to run 00+ guages and have them function correctly for the extra work you will like it in the end and you can get everything you need from a junk yard if your sunfire all you need is a dash harness and cluster cavalier you need a dash aswell



JBO since July 30, 2001

The problem with that way is my local yard has crushed all the j-bodys. So I know longer have access to any of them for parts. To be honest they don't have a thing really anymore, which is why I had to get the 00-02 2200 tranny from stoystown pa. Which is actually where I got everything for it. On another note who ever the guy was that brought the motor, tranny and other stuff over to the shop. Was saying he swapped a 3400 in a jbody, not sure if he is on here not though. Or even who he was to be honest. How ever you are correct my 99 has the evap in the back and the same pump as my 2000. Well it has the same ohm's any way but the crappy metal tank.

Any way I managed to finally get the wiring diagrams I needed. So I merged the grand am harness and jbody. Isn't to bad wiring it all up, how ever I am stuck on a few wires. I put left the stock pcm in the stock location and the grand am pcm is in the driver side fender. I also went ahead and change the lower/upper intake gaskets, fuel injector o-rings, thermostat and tb gasket. Then from already have a 2200 then a 2.4 I still had all the parts for most of the swap. I'm using the 2200 lower radiator hose which is pretty well a direct fit, just needs cut a little bit at the water pump. The upper radiator hose is the 05 grand am which is a direct fit. Then the heater hoses is also for a 05 grand am the fit pretty good as well. The only two things I have yet to test fit is the ac or powersteering lines.

The ac compressor I have is a 05 grand am's ,however it has the ports on the top. I don't believe the jbody lines can be bent to allow it to be bolted up though. So has anyone tried it, If not which compressor has the fittings on the back like the j-body? I believe I have seen the 3100 in the older grand am's with it there. How ever I can't remember to be honest. The power steering lines I have the 05 grand am's where they looks as if they may fit with a little tweaking, just haven't tried it yet.

Any way I can't start it as I don't have a flywheel yet. I ordered arp flywheel bolts, pressure plate bolts, flywheel, clutch kit, and a new a/c drier last night. So hopefully they are here mid next week and I can pull the motor back out to put it all in. Then here is some pics from last night, I still have a few hot wires to wire up. Then the ac, evap and haven't decided if I am going to wire the cruise up yet. I also need to put some of the wires back into the jbody pcm plugs. As I pulled some out as I was going to move it elsewhere but changed my mind.

Any way the grand am pcm is working and I can connect to it via the scanner. Just throwing a few codes for things I don't have hooked up yet. Since I know pcmforless from the f-body's, they are doing the reflash on the pcm. Where according to him I won't need to wire up the bcm, how ever I guess we will see. Then I am also wondering if anyone has a getrag shifter cable bracket laying around? I let stoys town take the 2.4 and broken getrag, how ever I didn't expect them to take the bracket off the 2200 tranny, so I never took it off the 2.4's.

Also I know there is a few people here that has done this swap, what did you guys do with the purple hot in only start wire from the pcm? I don't recall right off which connector it is, I want to say blue. The pinout of the pcm has it labeled as PPL 23 Crank Voltage. Where it then runs to the fusebox under the hood as Hot in Start. Where looking at the j-body diagrams everything is pretty much hot in run, bulb test and start. In which the only wire I think to even hook it to is the big purple one for the starter.

yeah but your car doesn't have a BCM and the 99 gauges wont read engine will run but unless your do what i mention above or piggy back a j body pcm into it the only thing that will function is speed and fuel. every idiot light will be on and your water temp and tach will be in operative

that wire needs to be fused wire it to your fuse panel 10A fuse it supplies the pcm with power



JBO since July 30, 2001

I should have mentioned it, but it is piggybacked. I am also aware that I don't have a bcm stock. Stock pcm is in the stock location with the grandam pcm tapped in mounted in the driverside fender. How ever I haven't really messed with the jbody's but stripping it and leaving it hooked up. I have to put some of the wires back in for some of the sensors, as I pulled them out to reduce the wire mess for now. As for the wire, I already have the grand am pcm wired up and working. I also hooked it up to the scanner to make sure that was all good, which it worked after I had to supply the data connector power. Not sure what the deal is with it at the moment, as the cig fuse is good. But jumping power to it is fine for now.

The only thing I have left to hook up as far as the grand am pcm goes is as follows:
The purple wire I mentioned (Not saying you are wrong or anything. But I may be misunderstanding, how ever this purple wire I believe based on diagrams is used to pick up I am trying to crank the 3.4. The grand am pinouts list it as going to a hot in only start. No run or constant. I would have to look at the fuse you mentioned to hook it to though. But on the jbody I am not seeing a hot in start only in the pinouts. Just the logic of the starter wire.
Fan wires and the relays (Using the grand am dual fans more then likely as I have them)
O2 sensor wires if i remember off my head
Then two pink wires that came out of the one fuse box plug of the grand am
Add in the jbody starter wires
Rerun the alternator and starter to battery wires, then do the ground (Battery was in the trunk before, but moved it back to the front sometime ago. Wires are there just have to rehook them back up)
Evap wires
Ac Wires
Figure out if I want to run cruise (Car never had it, though I wired it up for it not to work Probably a mistake on my part)

The only issues I have at the moment is:
In need of a getrag shifter cable bracket
Figure out which ac compressor to use (I believe the 3100 out of grand am will work or possibly the 05 grand am's with the line bent. Haven't really looked at the 05 to see if that is possible yet).
The purple wire I mentioned.
Then figuring out how I am going to go about the grand am fans wiring.

Other wise thanks for the help and any future help.

That purple wire IIRC, should run to a relay. Then that relay should be connected to the starter. However, the car may not have had that relay in there, as it wasn't put in there from the factory. It was a recall part that was added later down the road. The purple wire may have gone right to the starter.






i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick

Wait are we talking about the recall on the jbody? If so when the car was 2.2 I took it to have it done, along with the 2.4 harness had it done I am using right now. I actually am not talking about the physical starter wire. But on the grand am there is a purple wire on the grandam computer, that I have no idea what it actually is for. The pinouts state it as PPL pin 23 in I believe the blue connector Crank Voltage, upon following the diagram it goes straight to a 10 amp, labeled as hot in only start.

Where as I said the only wire I know off the ignition switch on the jbody for hot only in start wire would be the bigger starter wire. I guess my question is would that be the best place to tap into it or is there another wire? Then the other would be what is the crank voltage wire even for? As it looks like it doesn't have no affect on the pcm but looks like a trigger to tell the pcm it is trying to start. Sorry if I understood you wrong, but pretty sure we are talking about the same thing as far as the relay goes.

I'm not following your statements regarding the purple wire, but IIRC, the purple wire on the GA harness is for the fuel pump relay (unless you're talking about one of the purple wires that is paired with a yellow, but I doubt it), but you'll have to double check. The wiring diagram is on here somewhere. I don't recall any other purple wires.




Edited 1 time(s). Last edited Monday, April 09, 2012 5:21 AM

what does the scematic say purple 23 wire doesn't i'm building a harness right now, if its a crank wire does it hook to the starter relay if so you may not need it, because your car if the recall was done will have it mounted near the battery behind the headlight



JBO since July 30, 2001

The C100 from the j-body should have a fat purple wire coming out of it, going to either a relay, or to the starter. It should be hot in crank only. Sorry, I don't know right off hand what pin it's on.





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick

That is the pinout and I highlight the wire for which on I am talking about. Where that is the grand am pcm, how ever I haven't clear finished that connector at the pcm yet. Where I think I was just confused at what you guys were saying. As I wasn't aware the pcm controlled the starter relay. As I just look at the starting diagram to see it it purple to pin 23 then pin 76 that is yellow goes to the trigger on the stater relay.

In turn I would run the orginal starter purple wire from the c100 connector, to the pin 23. Then pin 76 that controls the starter relay to the recall relay you guys mentioned. Then hook that wire to where the original purple from the c100 connector hooked. Sound right to everyone else? Sorry for the confusion that was mainly my fault I believe.

Now that I look at the year and see how new, I'm not sure.

On my 05 Trailblazer, in order to start it all I have to do is click the key to the crank position. It doesn't matter if I let go and have it drop back to start, it will continue to crank until the engine starts. I know a lot of the newer GM's (at least trucks anyways) are this way. This also keeps me from being able to crank the engine with it already running.





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick

^^ Most, if not all, of the drive-by-wire vehicles are like this. I don't believe any 3400 was drive-by-wire, but looking at the diagram, I'm going to say it's definitely the starter wire. Some of the newer computers may have integrated the starter circuit in the ECM in anticipation of drive-by-wire. I'll have to look at one of the harnesses I have and see if they are set up like this. All of my harnesses are 02 and earlier, though.

lol ok guess I wasn't the only one confused The harness I know for sure is a 05 as it matches the diagram perfectly and every other little stupid grand am body plug. Was a task to figure out what plugs I was looking at on a harness I didn't pull. How ever I think I came by one or two wires that wasn't listed right. Though I can't remember if it was the grand am or jbody pcm with that issue now.

Here is the starting diagram, I added some color to it since my svgviewer is screwing up not doing it. How ever you can see where I was speaking about. I should be able to wire it up as pictured to the j-body recall relay. Just switch the wires out like this diagram. I will have to double check how ever. On another note I have access to all the body pinouts and diagrams for pretty much anything. Anything anyone may need or think of some I should post?


Also back to the ac, what compressors has people used with the grand am fans? Along with any of you guys have a spare getrag shifter cable bracket or know the part number?

Starting diagram looks good to me.

AC compressor, I dunno. I have the kind of AC where you crank down the windows.





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick

I used a Grand Am compressor, but the earl 90's Park Ave has been shown to work with the J-body AC lines. See the sticky.

Well I got it running the Saturday or should I say running for 2 secs at a time. Where I wired the factory recall relay into the grand am computer. Where it wouldn't trigger the relay to start the car, not sure why unless it was passlock. How ever I decided to wire it like the jbody to start it, where to my surprise it worked fine. So not sure what computer is doing controlling the relay besides the theft system.



I also think I have a plug wire crossed, so have to look at that. How ever I wanted to hear it actually running, so I wired the 4 hots into to hot all the time. Tapped the purple wire into the data connector under the dash. Then hooked up the ground. Where I then took a 2 2k ohm resistors wired in between the yellow signal wire for the grand am switch and the ground wire to it. Turned the switch on for 5-8 mins to reprogram the bsm to the resistor. Then I had to unhook the booster pack to kill the power to the bcm since I wired it up hot all the time. Where I got it to start and run fine.



Now back to the ac compressor, I have the 05 grand am one where the lines fasten on the top if it mounts like I was holding it. That or the bottom any way. How ever if it is at the top I may be able to get it to work by bending the line a bit. Though it is tight around the dual grand am fans. Along with the exhaust manifold is touching the heatshield plastic thing I had to cut down. So maybe a year of the ac compressor? I seen a older grand am in the local yard with the 3.1 that has the fittings in the right spot though.

Some older compressors from the 3100/3.1 engines have the rear connectors that the J-body lines will hook right up to. The GA 3100 may, but I haven't looked at one.

yeah that purple wire sends the power to the pcm which then pulls the coil in the pcm to close the contacts which then engizes the starter relay coil which closes the contacts on the starter relay sending power down the heavy gauge starter wire located on the starter itself

i have my car wired that way

use to have it wire like the j bodys



JBO since July 30, 2001

Well I wired the relay up as the grand am shows for, how ever I couldn't get it to work for nothing. The yellow wire that goes to the start relay on the grand am pc wouldn't output a ground, 5volts, 12 volts or anything really. So I left it as the j-body style now. The car is practically done now though, still have yet to drive it yet.

How ever I grand am dual fans working correctly from what I can tell. No more codes and I modded the fuse box to add the other two relays to it needed. Speedo is working fine from what I can tell. That is tell it hits 115 and goes instantly to zero till you slow down.

Now the issues I have is I still need to wire in the coolant temp gauge.
The tach I figured would be off any way, how ever I tapped into all the reference and 1-4 control wires on the grand am harness. Where no matter what it won't budge.
Then my theft system light is lit solid now after putting the 2.4 pcm back in. Thing is I don't know how I am suppose to reset it when the jbody pcm doesn't control the engine anymore. So anyone have ideas on that one?

The tach thing.... I still haven't figured that one out.






i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick

The tach is part of the data stream to the cluster, and the ECM picks up the signal from the ICM. The reference signal from the V6 ICM does not work on the J-body ECM. To my knowledge, no one has got a factory cluster to 100% work with tach on a 95-99 with a V6 yet. The only way I can see doing it is to reflash the datastream description file in the ECM, but none of the tuning software out there touches the datastream, so it has to be manually input into the .bin file, which, to say the least, isn't a small project. Since the software out there doesn't touch it, I don't know that the information is easily found as to where in the file that description lies.

That's the problem I was having.

Apparently I can't tap the factory ECU and MS into the wire for tach signal at the same time. It makes the engine cease to run. Unless I was trying to get at the wrong wire, which is possible I suppose.

I was under the impression that it was a 1x signal coming from the ICM, regardless of how many coil packs it holds. Theoretically then even a V8 ICM in there would read correctly on a J-body ECU. Either that, or I was thinking that you'd get something like a 2x from the 4cyl ICM, and 3x from the V6 ICM (due to having 3 coils instead of 2), in which case the tach should read, just be 33% too high.

I dunno, overthinking the problem maybe. How many pulses does the j-body ECU see per revolution? There has got to be an easy way to work around this. At least in my case, not sure about the guys trying to run a V6 ECU.





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick

SHOoff wrote:That's the problem I was having.

Apparently I can't tap the factory ECU and MS into the wire for tach signal at the same time. It makes the engine cease to run. Unless I was trying to get at the wrong wire, which is possible I suppose.

I was under the impression that it was a 1x signal coming from the ICM, regardless of how many coil packs it holds. Theoretically then even a V8 ICM in there would read correctly on a J-body ECU. Either that, or I was thinking that you'd get something like a 2x from the 4cyl ICM, and 3x from the V6 ICM (due to having 3 coils instead of 2), in which case the tach should read, just be 33% too high.

I dunno, overthinking the problem maybe. How many pulses does the j-body ECU see per revolution? There has got to be an easy way to work around this. At least in my case, not sure about the guys trying to run a V6 ECU.

There is a separate tach output on the V6 ICM that the 2.2 ICM doesn't have. The ECM doesn't read the same signal as a tach output. It reads the buffered output, that I'm actually not sure of the signal, but yes, if you try to split that one, the ECM doesn't read it properly, so the V6 computer won't run the motor.