flyboyX's obd2 s52 engine swap blog

[flyboyx]

this week i started getting serious about getting that engine in my car. i have asked quite a few questions here and received lots of good answers from fellow r3vers. since there is not a lot of thorough documentation about obd2 swaps, i thought i would try to get as much down in this thread as possible. this is my way of paying forward to all of you that have helped get me to this point. if you have constructive comments to make this a better thread, please post them here. if you have individual questions about some point for your swap, please pm me for that because i would like to keep this thread as clean and on topic as possible. if it is something that will improve this thread, i will post that up as well. updates may not come every day or every week, because of other life obligations like work, divorce, renovating a house flooded by hurricane ike, time with new girlfriend, etc, but i will try to post updates here every time i make progress.

ok, with that said, my car receiving the transplant is a 91 318i convertible. my donor car is a 46,000 mile wrecked 2000 MZ3 that i found on local craigslist for a stupid cheap price.

the engines have been out of the cars for a month now. the m42/getrag 240 was sold right away and shipped to a guy in north carolina. my s52 is hanging on an engine stand in my garage next to the e30. i removed the oil pump and windage tray so i could pull off the main bearing caps to check the inserts. i was planning to buy all new bearings and rod bolts, but the main bearing inserts look new, so i have decided to not touch the rods and just put the mains back together and retorque them. i guess i will spend that part of the budget on a stage 3 clutch. i am waiting for my gaskets to arrive in the mail so i can get the engine back together.

i have a nice close ratio zf 5 speed that came with the mz3, but i have elected to use a getrag 260 out of one of my e30 parts cars. my reason for doing this is because the car is a convertible. i will never race it on a track. my only plans are to run it on the street. i wanted the .81 overdrive that the getrag affords for fuel economy and quieter drivability during highway use. i am going to use the dampered e36 flywheel and upgrade to a 6 puck stage 3 clutch and pressure plate. of course, it goes without saying that i put the z3 shifter on the getrag.

my e34 525i oil pan and dipstick tube came from various local junk yards. i spent about 60.00 here. i intend to buy the oil pump pickup tube new.

i found an obd1 manifold from a 93 325i in the local pick a part junk yard. it included the hoses, mounting brackets, throttle body, injectors, and also the plastic cover that goes over them. after a little flirting with the hispanic girl that prices the parts, i walked out of there only paying 75.00 for the assembly. i know that i wont use the throttle body or the injectors, but i will need the rail and some of the hoses undearneath.

for the exhaust, i plan to use the stock mz3 exhaust from the resonators forward. this includes the cats and all four o2 sensors. someone on this forum told me that it should bolt up with little or no modification. we will see. after the resonators i plan to have a stainless custom 3"single pipe made to get the exhaust back to the muffler. i have already purchased a 3" inlet to dual 3" outlet black vibrant muffler from verocious motor sports. lots of people seem to really like that muffler and i wasn't very expensive. about 140.00 shipped.

the differential is the 3:25 lsd from the mz3. unfortunately, during the accident, the finned aluminum cover plate was broken beyond use, so i used the cover from one of my e30 parts cars. one of the axle shafts poped out during the accident and had been that way for some time. unfortunately, this means i have to take the diff apart and clean out all the dust and grit.

my convertible e30 325i parts car had a new driveshaft, so that is going in my swap.

i will be modifying my trans mount and the shifter linkage in the near future.

smaller brake booster came from said junkyard above. it is out of an early model vw rabbit. the bolt pattern on the master cylinder side and also the firewall side is exactly the same as e30. of course the input shaft was too long and unfortunately, after the threads, it was about 1/16 of an inch larger diameter. this making it very diffacult/impossible to rethread. my solution was to take both boosters apart and swap the e30 input shaft into the rabbit booster and put everything back together. i will have to let you know how it works out.

plan to use the e36/mz3 radiator. i still have the m42 rad, but cant see any reason to reduce the capacity as the e36 version seems to fit perfectly in the late model e30 mounting brackets.

i had to purchase e36 engine mounting brackets from a junk yard because mine were both broken from the accident. i ordered a new set of e34 525i mounts. they are so cheap(like 10.00 each), i can't imagine anyone reusing an old set.

all of my new parts associated with the engine are coming from pelican or bma auto parts. i priced everything at bav auto, bma and the dealer. bma auto was close to the same as pelican, bav auto was slightly more. as you can imagine, the dealer was much more expensive. everyone i talked to was very professional and helpful, though.

i have lots of suspension upgrades to the car but they really aren't assocated with this swap, so i will list all of this in another thread sometime down the road.

the most important part of the swap is the wiring and i am still working on getting it figured out. i downloaded the electrical troubleshooting manuals online from a couple of different sources. it is amazing how different two etms that are suposedly from the same make and model can be. hmmm....

as i stated above, this is going to be a completely stock obd2 swap with ews 3.(except i will use an obd1 manifold) i have spent a lot of time studying the mz3 etm. i have elected to strip the entire body wiring harness from this car. this seems like the easiest way to go because there are a lot of wires in there i need to use. in the top left corner of the photo below, is the sub wiring harness for the fuel tank pressure sensor and also the sensor itself. hard to see in the photo, but the sensor is connected to a hose that goes to two orifices. one is in the filler neck and the other in the top of the tank. the wiring for this sensor are pins 5,6 and 7 of the x6031 plug. i have not had the tank out of my e30 yet, but i will find a way to attach the sensor to the tank and post the info here. i intend to swap the 14ish gallon tank with the 16.4 gallon tank from one of my parts cars anyway.

[hoveringuy]

Looks like you've done your homework. There are not a lot of well-documented OBD2 swaps here so kudos to you. I'm interested in seeing your progress!

[flyboyx]

the obd2 cars have an egr valve attached to the exhaust manifold. this valve is connectied to a hose that goes to a filtered air pump located on the passenger side next to the ecu box. below is a photo. the wiring for this air pump is located in the s52's engine harness. initially, i planned to delete this pump. i haven't seen any conversions where it was maintained. after spending sometime thinking about it, i believe i am going to relocate my convertible's battery to the trunk and mount this accessory in the battery locaton. can't seem to think of a good reason not to install it.

the mz3 had asc traction control and i have no intention of installing that system on my car. the x6031 plug has 4 wires associated with asc. they are pins 9,10,11, and 12. instead, i will be using a couple of these wires to route the oil level sensor signal into the cabin. oddly, the mz3 didn't have an oil level sensor, but the e34 oil pan does. the m42 also had one. i will just route the wires i need from the ecu to the sensor on the engine side. on the body side, i plan to route some of the wires associated with asc over to the instrument cluster so the signal can go to the light on the dash.

lots of guys make a harness adapter to morf the x20 plug of the s52 engine harness to the c101 of the e30 body. i intend to use both sides of the x20 and x6031 to route my wires into the body harness. i will cut the c101 out of the e30 harness and repin or solder the wires to the body side harness plug of the e36. i think this will look a lot closer to the way it would come from the factory.

the obd2 reader/data port interface is an easy one. there are four wires coming off the obd2 port. two are brown chassis grounds, one is red/yellow power in to the port(goes to a 5amp fuse in the fuse box), the other is wht/vlt with yellow dashes. this one routes from the ecu through the x6031 plug at pin #4.

[jahnaboi]

EDIT: I'm dumb. Lets get this project on the way!

[mongule]

For wiring make sure you wire the correct wire for engine speed to the dme
Depending on your car you might have to splice into the back of the cluster.

It is different then Obd1 cars and will not let you rev higher then 5000 rpm if you dont wire it in correctly.

I forget which pin exactly it was on the dme itself but check the Etm. Took me a while to troubleshoot this so just a heads up for your swap.

[matt]

You aren't actually going to retrofit EWS3 are you? I assume that was a typo.

The car will run perfectly fine with no OBDII port BTW. All the same data is available at the 20 pin diagnostic port.

[flyboyx]

You aren't actually going to retrofit EWS3 are you? I assume that was a typo.

The car will run perfectly fine with no OBDII port BTW. All the same data is available at the 20 pin diagnostic port.

matt,

thank you for your comments. yes, i am planning to run ews3 for lack of knowledge of any better options. in looking at the wiring diagrams, it doesn't look that hard? i have already pulled the wiring out of the harness. i am planning to run the engine stock in my car. the only software i know of to delete ews requires a "stage 2 or 3" upgrade or some crap like this. i wouldn't mind doing the upgrades, except most people i know that have done the maf, injectors, and software upgrade usually wind up spending a lot of money and have a car that runs worse than it did before they started. if you or anyone else has any better options, please let me know.

[matt]

EWS3 started with the e46... you should have an EWS2 box. There are a couple good wiring diagrams on here, it's not hard to make work.

Get it running well stock, then worry about modding it.

[flyboyx]

EWS3 started with the e46... you should have an EWS2 box. There are a couple good wiring diagrams on here, it's not hard to make work.

Get it running well stock, then worry about modding it.

ews3 is what the etm says. the wires that i pulled out of the harness match the color coding stated in the manual. let me know if i am missing something.

btw, i thoroughly agree with you about getting it running in stock form initially. i want to have a baseline to get a feel for how it should run and also clear any check engine light issues if possible before i even switch to the obd1 manifold.

for some reason, i am thinking that 1998 was the first model year for the e46. am i in uncharted territory here? from what i can tell by comparing my etm diagrams to the ews2 diagrams that etxxz posted in his wiring kamasutra, there is one major difference between the two versions. it appears that ews2 has two different modules. one main and one transmit/receive module. for my setup, there is only one box that appears to contain both functions. it has a plug containing about 15 wires or perhaps a few less. the main starter wire from the ignition switch as well as the wires for the terroidal antenna are all included in this 1 module.

[flyboyx]

here is a link to some educational material for bmw's ews. it coversews 1(which is a joke) ews 2 and ews 3. there is a lot of info here here that i didn't know. it is pretty technical and not the easiest reading, but if you are going to do a swap and maintain ews2 or 3, i would say its a necessity. http://www.europeantransmissions.com...0EWS%20BMW.pdf

after reading through the material, i know that i have ews 3d in the mz3. it is very similar to ews2 except there is only one ews module instead of 2. also, ews 3 uses a rolling code system that changes the code every time the engine is started. apparently it is important not to attempt to start the car with either the dme or the ews module disconnected from the electrical harness. this would result in one of the modules being out of phase with the other and result in a no start. sounds like that would need to be reset at the dealer.

there really are only 2 wires that i am concerned about hooking up at this point. according to my diagram below(top left corner), pin 15 from the ews is a blue/red/yellow wire that travels to pin 10 of the "alpine anti theft module" and also pin 4 of the body electonics control module. additionally, pin 13 of the ews is a black/green wire that travels to pin 15 of the body electronics control module. these wires tell the ews if the doors are in a locked state. if the signal shows locked, then ews won't allow the car to be started. i need to figure out how to connect these the the e30 central locking system. as you can see by the diagram, those items show transisterized switches, so i don't think it should be to hard.

here is how the wires on the ews 3d module pin out:

1 terminal 31 ground (brn)
2 terminal 30 goes to a 5 amp fuse power in hot all times
3 p/n input. (manual trans) goes to hall effect switch on clutch to complete a circuit if clutch is depressed. to gnd if not.
7.5 amp fuse hot in accy, run, and start
4 diagnostic bus data link (wht/violet)
5 engine speed to instrument cluster engine speed (bk) to pin 20 of x20 plug
6 bar release code input
7 starter output (bk/ylo) goes through pin 18 of x 20
8 ign starter switch input from ign sw (gn/bk)
9 terminal R 7.5 amp pwr in
10 ring antenna (blu)
11 ring antenna (wht)
12 reserve (x)
13 locking states (blk/grn)
14 data link to dme (grn) goes through pin 7 of x 20
15 unlock car (bl/rd/ylo dashes)

as i stated above, i don't have all of these figured out yet. as i make new discoveries i will change this accordingly.

[Jean]

Next time "PrtScrn" and paste into ms paint or any other graphics program and save / attach ;)

[flyboyx]

well, i haven't updated in a while, but here is what has been going on with my project. this is a photo of the body side of the mz3's wiring harness that i pulled out of the car. i think if you have the car and the time, this is the way to go. pictured is the body half of the x20 and also the x1805 that plugs into the ews 3d(the large white plug in the photo below). i also have a little harness for the x6031 plug as well, but you get the idea. these harnesses are going to be spliced into my e30's wiring. there is no particular reason for the length of the individual wires other than i followed them to the termination point to cut them off. there may be ten feet of wire hanging from the plug on a wire that only needs a foot, but i figure its better to take the whole thing so i can minimize the splices during the solder phase.

looking at the etm diagrams is one thing. however, there is no way to quantify the knowledge and associated learning you achieve by taking a cars wiring harness apart to trace/label each individual conductor. sounds cheesy, but it sort of gives you a zen of understanding about your car. i can sit here in front of my computer and type on this thread all day, but nothing will get you there like doing it yourself

[flyboyx]

here are my 4 wiring diagrams that follow. this one of the x20 body harness to c101 body side harness. there is a hell of a lot of research here. please look these over closely and feel free to pick my diagrams apart if you can. any constructive criticism will be well received. revisions will be posted as they come in.

edit a quick edit 06 Oct 09: for those of you that have read the complete thread, you know that i have changed a few things from these diagrams. as of this date, there are about a half a dozen wiring changes i have made to make this engine run properly in my car. when i do get my swap finished and running with no check engine light fault codes, i will post a revised version of these diagrams. in the meantime, you can pm me with specific questions and i will answer them to the best of my ability. i have found that my wiring situation is quite different than all the other diagrams posted on this forum. i think these will probably only apply specifically to 99 and 00 Mz3. when i get my revisions completed, there will be many basic guidelines here that will be useful in a variety of situations.

[flyboyx]

this is the x6031 plug. i am thinking about splicing the few wires i intend to use from this plug into the x20(eliminate this x6031) to make the engine compartment less cluttered, but at least here is a baseline. the 15 pin x6031 is commonly used by bmw in bazillions of automatic cars as the plug to transfer wiring from the transmission to body.

[flyboyx]

here is the diagram for ews 3d