S52 OBD1 Conversion Complete...here's what I learned.

[bubbajan21]

Just found this thread. This is an AMAZING write-up. Thanks!

[DaveAZ]

Great thread!

I have a 3.2 that was converted to OBDI by it's previous owner and I am trying to reverse the process. I have the engine out of the car and I will be putting into an OBDII car. I started my own thread and posted pictures in order to determine exactly what I need to do in order to return to OBDII. Please click here to offer help as to what I need to do: http://forums.bimmerforums.com/forum...5#post22835305 Thanks!

[dRock13]

nice numbers. But why the conversion?

[boomersooner523]

nice numbers. But why the conversion?

See first page.

[BMWMPow3r]

how do you use the obd1 crank position sensor with the obd2 timing cover?

[k,elnazer]

Hi all,

Just wanted to ask you as you seem have done this conversion more than once,
Do i need a chip so the eninge run or why will i need the chip.? i notice all ppl doing it are using some chip.
Thanks

[DaveAZ]

Hi all,
Do i need a chip so the engine run or why will i need the chip? I notice all ppl doing it are using some chip.
Thanks

The chip is for performance enhancement only. With OBDI you accomplish engine tuning by changing the chip inside the DME (computer).

With OBDII cars from 1996 to 2002 you have to either send your DME to a company who will upload a custom tune, use a "shark injector," or have your program custom tuned on a dyno.

[CMG]

Either

[sleeps41]

Ok fanatics, here is my situation, I had the conversion done on my 93 using an S52 from a 98 M3. The mechanic was able to find me a metal obd1 valve cover, used the obd1 dipstick since he used my old oil pan from my m50tu, which means that the cyclone separator used on the obdII system was ditched. My issue is that the car is burning an outrageous amount of oil. Blue smoke is coming from the tail pipe when warming up, and oil is all in the intake manifold. Can I replace the cyclone separator unit (once sourced) utilizing the obdI valve cover? If this is the case, I found someone in the forum that builds modded obd1 dipsticks to accommodate the hose coming from the separator. Are there any other suggestions or diagrams anyone may have to solve this issue because purchasing a quart of synthetic oil every 300 to 500 miles is getting out of hand. Trying to figure out where all the hoses will connect to utilizing the obdI valve cover and obdI intake manifold. Thanks.

[Viper3812]

Do I have to use the OBD1 fuel rail or can I just use my OBD2 fuel rail? Is the main reason for the mounting on the manifold?

[biglou911]

Do I have to use the OBD1 fuel rail or can I just use my OBD2 fuel rail? Is the main reason for the mounting on the manifold?

U can use obd2 fuel rail


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[biglou911]

Love this thread !!! God bless OP !!!


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[BrokeMyWalletM3]

ok so i realize this thread is very old now, but there are many advantages to converting to OBD1. One of the biggest problems I am having currently is figuring out a tune for my 96' 328is turbo build. In 96' BMW switched from Bosch DMEs to Siemens DMEs. The Siemens DME is is ONLY REFLASHABLE. You cannot put a chip in these and can barely rewrite anything in them. In addition, BMW installed a more advanced EWS2 system that you cannot delete without a professional rewriting your Siemens DME. You cannot swap DMEs in an OBD2 e36 as well. Therefore, tuning of any sort (unless done by turner or dinan, etc.) is virtually impossible. If you live in Florida, you have an advantage tho because there is a God among men named Nick Glantis that owns Technique Tuning that CAN rewrite, tune, and delete the EWS2 from your OBD2 setup. ($$) In 95' BMW had EWS2 as well but it was still OBD1 so you could actually fin the pin from the Bosch DME to the EWS module itself, and cut the wire, allowing swapping of most DMEs. But 96' and up got the poop stick so... converting to OBD1 is very advantageous when heavily modifying your e36 i.e. forced induction. I hope this helps ppl and i apoligize if it was said already in another thread. Also, you can now swap an m50 manifold on an m52 without converting the whole car by using an adapter from Turner. Its a great upgrade as long as you have s52 cams and a shark tune (also Turner).

[DaveAZ]

BMW installed a more advanced EWS2 system that you cannot delete without a professional rewriting your Siemens DME. You cannot swap DMEs in an OBD2 e36 as well. Therefore, tuning of any sort (unless done by turner or dinan, etc.) is virtually impossible.

You may want to search around a bit on here. I swap my OBDII computers out whenever I have the urge and align my EWS in seconds. The only shortcomings I can think of to the OBDII is the added emissions. It changes your fuel mixture based on the secondary O2 sensors instead of based on engine performance. There is also that secondary air pump thing. There are people who sell computers which have been modified to eliminate these issues.
Swapping chips as opposed to flashing are just different methods with the same end-result. There are plenty of individuals who can flash the OBDII DME's. The diagnosis software forum on here has most of the information you would need to be able to do it yourself as well.

[BDR]

This thread has been very helpful. I just performed this conversion and S52 swap on my E34. My car fired up on the first try at cranking with the red 413dme, 21-lb pink injectors, and larger 740iL HFM, I still need to get the correct OBD1 Cam sensor and Knock sensors.

[juka]

HI I am jsut wondering if someone can help me, please.

I ve done a obd1 conversion but the conectors warent labeled. SO now I am asking if some one can halp me to find where goes where. The car works.
But the vanos, 2 temperature senzors, IVT are not conected...
I am thinking to sort this out by wire color. So if someone could please help me I would be greatful.
BTW sory for my poor english!

[biglou911]

I Dont have my harness right now. Plus I wanna try and do obd2

[juka]

HI I am jsut wondering if someone can help me, please.

I ve done a obd1 conversion but the conectors warent labeled. SO now I am asking if some one can halp me to find where goes where. The car works.
But the vanos, 2 temperature senzors, IVT are not conected...
I am thinking to sort this out by wire color. So if someone could please help me I would be greatful.
BTW sory for my poor english!

anyone??

[Frank@AchillesMotorsports]

We also offer a couple of nifty bolt on solution for the OBD-2 guys who don't have a pipe there like the OBD-I heads & for S54 engines as well.

From Achillesmotorsports.com

OBD2 to OBD1 Conversion Coolant Hose Adapter for E36 E30 M50 M52 S52 Engines <---- Link

OBD2 to OBD1 Conversion Coolant Hose Adapter for E36 E30 M50 M52 S52 Engines replaces the metal pipe from the OBD2 engines with a hose adapter that allows the installation of a normal OBD-I coolant hose. This is useful when converting an OBD-II Engine to OBD-I or when swapping 3.2L or 2.8L engines into a car which has been converted to OBD-I like an E30. It is also useful when using an OBD-II head on an OBD-I car.

The simple kit comes complete with necessary 2 O-rings, extended bolt, Nylon Lock Nut & washers to make this a quick install. No need to wait! It is also completely reversible!

From Achillesmotorsports.com

Racing Coolant Pipe Plug - E46 M3, Z3M, Z4M - S54 Engines <----- Link

This plug was developed for racing to eliminate the factory coolant pipe that runs underneath the intake manifold on S54 engines. Our quick and simple kit comes complete with necessary O-ring, extended length bolt, Nylon Lock Nut & washers to make for a quick install. No need to wait and It is also completely reversible!

[m3killaa]

I'm having issues with no spark or fuel as well. 1994 325is to 1997 s52 conversion. Used all brand new obd1 sensors, obd1 harness, red label 413 DME, double checked all sensor connections maybe even triple checked. It will crank but not start, no check engine light. I checked resistance on crank sensor as well as used my old working sensor, no change. I should not have EWS issues but am going to try cutting the wire to see if that's the problem. Only things to mention are the one o2 sensor is not connected, i was told that doesn't matter, i tried two dme's to make sure it wasn't that. Jumped fuel pump relay and fuel pump works. Both the main dme relay and fuel relay should be working as they were before swap. What should i check!!!! Going crazy the build was easier than figuring out the fuel and spark issue

[NHbmw325I]

Do you have the engine mount bracket ground installed? That caused my car to just crank.

[trykyle]

Hey I have a 98 323is that I am changing over to OBD1. I would like to see if I could get a link to that program that you have. From what I see it is in detail. Thanks

[bluptgm3]

Hey I have a 98 323is that I am changing over to OBD1. I would like to see if I could get a link to that program that you have. From what I see it is in detail. Thanks

Why? What are you hoping to gain?

[petrothegreat]

so I just finished my swap and im not getting spark or fuel.. did you have any issues with your initial start up

[aceprowler]

Great write up!

I've been in the process for a couple weeks now of getting all the parts for M50 intake install on my 98 M3 and nice to see I can switch to OBD1 if I really needed to.

This site is awesome!

Thanks again!