maurolin
11-12-2004, 12:42 AM
Here's the story of my first S52 OBD1 conversion into my 1995 318ti. this is a BRIEF overview. I might miss some stuff... so feel free to add to it!.
I went to a junker and bought a 325i 1995 auto wiring harness, a 413 DME and an intake manifold with a fuel rail.
All this was going to go in a 1995 318ti which gave me an advantage for the car being OBD1 already.(no need to replace EWS or key) sync dme only. I have the scan tool
Then I started looking for all the needed sensors and parts to complete the kit.
Cam shaft sensor (side of the vanos. USE a obd1 sensor because of the connector)
Crank shaft sensor on the OBD2 is located on the back left side of the engine and it will NOT be used. you leave the obd2 sensor there unplugged. The cracnk shaft sensor is actually located on the front of the engine reading the harmonic balancer (USE OBD1 or 2 MANUAL TRANS! H BALANCER) and that's one of the most importants sensors on your conversion.
The OBD2 Knock sensore CAN be used, but you need to find the OBD1 connectors to SOLDER and attach. Make sure there is NO loss or gain on the resistance., but if you can afford to get new OBD1 knock sensors.. that's the way to go.
Temp sensors on the Head. This is where it gets pretty tricky. OBD1 had 2 sensors on the left side of the head beneth the manifold. 2 sensors 4 leads, 2 connectors. OBD2 has 1 sensor, 4 leads 1 connector. you CAN use the OBD2 sensor and split the 4 leads into 2 connectors. (Connectors are found at shops junk yards etc. or make your own, but more work.) this is what I did. I used the OBD2 plug, otherwise I would of had to drill and Tap the head for the second Temp sensor, and that is no fun... to risky.
The Valve cover. This is where you need to get creative. OBD1 metal cover, OBD2 plastic cover. The MAIN purpose of this is to remove the cyclonic oil separator which is at the other end of the plastic hose that connects onto the left front side of the head on the OBD2. That hose and the oil separator will be removed and replaced by the OBD1 nozzle that you need to grind down till it fits with the "O" ring in the obd2 plastic inlet of the Head. then attach a hose to one of the 2 ports the OBD1 throttle boot has. (you need an OBD1 throttle boot and coupling)
OBD2 has a bunch of vacums under the manifold, but only 1 will be removed. It is the Exhaust flaf vacul. a Black hose with a blue strip and a white pcv valve on it. GONE. The Manifold. This is the "hard part". (just cause I hate it) but you need an OBD1 idle control valve and hoses, and the OBD2 manifold has the bolts that hold the plate that hold the dip stick closer toghether than the obd1, so I cut the plate in 1/2 and got 2 plates out of 1. Now, the dip stick would work BEST if you replace the oil pan for the OBD1 but IT IS NOT WORTH IT!. make a new plate!.
You can use either the OBD2 OR OBD1 throtthe body. you should change the boot to obd1. and while you are at it, if there is no snow where you live... remove the heatting hoses from the trottle body and loop them straight toghether. You also need an OBD1 HFM Air flow meter but if you are going through all this hassle, GET THE EURO HFM.
Then you have the charcoal canisters and tank ventilation valves whick must be installed.
now... the EXHAUST MANIFOLDS! wow... this was a PITA. Take e'm off. remove the secondary air supply and injection pipes.
What I did is I had the OBD2 Steel manifolds weldded shut (2 grooves where the air gets injected into the system) and I read that the cast iron OBD1 ones cannot be weldded, they are Heavier, rust nasty and are less heat efficient. I left the PRE CAT o2 sensors on the manifolds and cut off the cables. (you can use them for EGT gauges or Stoich/rich gauges)
The fuel pump. Ofcourse... more volumen. i used a 1995 M3 one.
Easy swap, bad smell.
Get an 80 degree thermostat and a new temp sensor for the radiator... yes you need a 6 cyl. radiator.
Finally the exhaust. OBD1 has 1 PRE cat o2 sensor that measures BOTH (1-3 and 3-6) pipes. I used t5he OBD1 mid pipe. While you are at it... remove the cats (no I NEVER did this! EHHMmm) for the OBD2 mid pipe, remove cats and have a muffler shop weld an o2 sensor thread between the 2 pipes on a bridge.
The software: In my case.. 3.2L S52 HFM, Flywheel, CAI, Trackpipe, Fan delete mod, 21.5 injectors(stock obd2) $350 from Active autowerks.
The tranny from a manual Ti is the same as that of the '95 M3.
I forgot to mention that the 318Ti sway bar needs to go (rubbs with the oil pan) the cluster needs to be changed or you'll be reading 8K RPMs when the car is really at 3500,
I went to a junker and bought a 325i 1995 auto wiring harness, a 413 DME and an intake manifold with a fuel rail.
All this was going to go in a 1995 318ti which gave me an advantage for the car being OBD1 already.(no need to replace EWS or key) sync dme only. I have the scan tool
Then I started looking for all the needed sensors and parts to complete the kit.
Cam shaft sensor (side of the vanos. USE a obd1 sensor because of the connector)
Crank shaft sensor on the OBD2 is located on the back left side of the engine and it will NOT be used. you leave the obd2 sensor there unplugged. The cracnk shaft sensor is actually located on the front of the engine reading the harmonic balancer (USE OBD1 or 2 MANUAL TRANS! H BALANCER) and that's one of the most importants sensors on your conversion.
The OBD2 Knock sensore CAN be used, but you need to find the OBD1 connectors to SOLDER and attach. Make sure there is NO loss or gain on the resistance., but if you can afford to get new OBD1 knock sensors.. that's the way to go.
Temp sensors on the Head. This is where it gets pretty tricky. OBD1 had 2 sensors on the left side of the head beneth the manifold. 2 sensors 4 leads, 2 connectors. OBD2 has 1 sensor, 4 leads 1 connector. you CAN use the OBD2 sensor and split the 4 leads into 2 connectors. (Connectors are found at shops junk yards etc. or make your own, but more work.) this is what I did. I used the OBD2 plug, otherwise I would of had to drill and Tap the head for the second Temp sensor, and that is no fun... to risky.
The Valve cover. This is where you need to get creative. OBD1 metal cover, OBD2 plastic cover. The MAIN purpose of this is to remove the cyclonic oil separator which is at the other end of the plastic hose that connects onto the left front side of the head on the OBD2. That hose and the oil separator will be removed and replaced by the OBD1 nozzle that you need to grind down till it fits with the "O" ring in the obd2 plastic inlet of the Head. then attach a hose to one of the 2 ports the OBD1 throttle boot has. (you need an OBD1 throttle boot and coupling)
OBD2 has a bunch of vacums under the manifold, but only 1 will be removed. It is the Exhaust flaf vacul. a Black hose with a blue strip and a white pcv valve on it. GONE. The Manifold. This is the "hard part". (just cause I hate it) but you need an OBD1 idle control valve and hoses, and the OBD2 manifold has the bolts that hold the plate that hold the dip stick closer toghether than the obd1, so I cut the plate in 1/2 and got 2 plates out of 1. Now, the dip stick would work BEST if you replace the oil pan for the OBD1 but IT IS NOT WORTH IT!. make a new plate!.
You can use either the OBD2 OR OBD1 throtthe body. you should change the boot to obd1. and while you are at it, if there is no snow where you live... remove the heatting hoses from the trottle body and loop them straight toghether. You also need an OBD1 HFM Air flow meter but if you are going through all this hassle, GET THE EURO HFM.
Then you have the charcoal canisters and tank ventilation valves whick must be installed.
now... the EXHAUST MANIFOLDS! wow... this was a PITA. Take e'm off. remove the secondary air supply and injection pipes.
What I did is I had the OBD2 Steel manifolds weldded shut (2 grooves where the air gets injected into the system) and I read that the cast iron OBD1 ones cannot be weldded, they are Heavier, rust nasty and are less heat efficient. I left the PRE CAT o2 sensors on the manifolds and cut off the cables. (you can use them for EGT gauges or Stoich/rich gauges)
The fuel pump. Ofcourse... more volumen. i used a 1995 M3 one.
Easy swap, bad smell.
Get an 80 degree thermostat and a new temp sensor for the radiator... yes you need a 6 cyl. radiator.
Finally the exhaust. OBD1 has 1 PRE cat o2 sensor that measures BOTH (1-3 and 3-6) pipes. I used t5he OBD1 mid pipe. While you are at it... remove the cats (no I NEVER did this! EHHMmm) for the OBD2 mid pipe, remove cats and have a muffler shop weld an o2 sensor thread between the 2 pipes on a bridge.
The software: In my case.. 3.2L S52 HFM, Flywheel, CAI, Trackpipe, Fan delete mod, 21.5 injectors(stock obd2) $350 from Active autowerks.
The tranny from a manual Ti is the same as that of the '95 M3.
I forgot to mention that the 318Ti sway bar needs to go (rubbs with the oil pan) the cluster needs to be changed or you'll be reading 8K RPMs when the car is really at 3500,