S52 OBDII Swap Not Starting

[BavarianGonzo]

Swapped an S52 from a 1999 M3 into my 1986 325e, kept the OBDII wiring harness and intake manifold, running an OBDI fuel rail and FPR. Finally got everything hooked up today and I was able to crank but it will not start/run. I'm sure there's something obvious that I've forgot, here's where I stand currently:

1. The first thing I noticed was that as soon as I turn the key on the idle air control valve starts buzzing rather loudly and does not stop. So I pulled the ICV, sprayed it with carb cleaner, verified that the valve is free (actually it seems too loose? when I shake it the valve inside just kind of flops around). Perhaps I have a bad ICV, but that shouldn't prevent me from starting, right?

2. When I turn the key on the fuel pump primes. I have not verified that the fuel pump relay is pulling in while cranking (need an extra pair of hands). But I would think there would be enough fuel pressure at the rail that it should at least be able to fire... when I pulled the fuel feed hose off the rail it sprayed gasoline everywhere so there is some decent pressure there. Would it be worth jumpering the fuel pump relay always on while cranking to verify? Perhaps I should pull the injectors out and actually see that they're spraying?

3. I have not yet verified spark when cranking but I have verified that the unloader relay (X6326) is pulling in (12V on the green and red wires as long as key switch is on). That was the issue in this thread, I believe:

http://www.r3vlimited.com/board/showthread.php?t=335396

4. I have a bluetooth OBDII adaptor that I use with the Torque app to pull codes off the ECU. The only CEL code that it's throwing is for "running losses valve" which I don't have hooked up, this shouldn't prevent me from running I would think, unless everyone else who doesn't run it has to have it flashed out.

5. I'm not able to see any movement on the tach when cranking, does this indicate that the ECU isn't seeing the crank position sensor signal? I imagine the tach would barely move even if it did see the signal. Does no tach while cranking = no CPS? Yes, I have an early model car so I believe this signal is coming from C104 (I have C104 pin 1 connected to X20 pin 20)

6. I think I've successfully disabled EWS, but it's hard to know for sure. What is the most obvious way to tell? Perhaps based on the fuel pump relay? To be more specific, I changed the value at offset 0x08 from 0x16 to 0x96, based on information I found here:

http://www.openms41.org/tuning/known-maps-info/performance-controls/ews-delete

If anyone has any comments or thoughts of what I should do next in my troubleshooting feel free to respond. In the meantime I'm going to try to get someone to help me troubleshoot things while cranking (verify spark and fuel relay) and will update this as soon as I know more.

[sweet3]

Welcome to the 24v club!
My first question is why are you running the obd2 intake with the obd1 fuel rail and fpr? How come you didnt stick with the obd2 fuel rail and fpr?

Okay, now to the problem at hand...
- I dont think the ICV would prevent it from starting...only idling.
- I would take both fuel lines off by the intake manifold and hold them in a bottle. Then turn the key and make sure fuel is coming out. Dont bother pulling the injectors out yet, that will make a mess lol. If fuel is coming out of the lines, then the injectors should be spraying. If not, then try jump the fuel pump relay.
- No movement on the tach while cranking is normal I think. IIRC, mine doesn't move either.

Next steps I would take:
1) Have you double checked all of your grounds? (main ground strap near the engine mount, the one on the shock tower, etc.)
2) Are you 100% that EWS is disabled?
3) Has your ecu been opened by a previous owner? If so, is there a chip in there still? (I had a problem with mine not starting. When I checked the ECU, the PO had taken the chip out already )
4) Crank sensor is a possible culprit (But I think the ECU should throw a code..not 100% on this though)
5) Have you connected your fuel lines up correctly by the intake manifold?

I think that's a good list for now. Hopefully one of these will help!

[m3j0n]

sure sounds like EWS is not disabled to me...... While a bad ground seems like it could also be the cause, its not likely given the cranking. when a ground is not strong enough to start the motor, it usually wont even turn it over multiple times. If the motor was running in the 99 before removal, it is unlikely that the crank or cam sensor went bad (unless you pinched a wire, or hit the sensor when doing the swap).

Sweet3 - OBDII computer should not have a "chip" like a OBDI Bosch Unit from what I understand.

[m3j0n]

not that I want to add fuel to your frustration, but.......








Shouldve gone OBDI. :) good luck!

[sweet3]

Sweet3 - OBDII computer should not have a "chip" like a OBDI Bosch Unit from what I understand.

Good point.. lol

[328ijunkie]

Sounds like EWS...

And OBD2>OBD1 anyday ;)

[328ijunkie]

Fuel lines backwards?

[BavarianGonzo]

Alright, I did some more troubleshooting after work today and I think I have it mostly sorted out. Here's what I did:

1. First I uploaded the 24kb partial from the ECU, sure enough the value at offset 0x08 (which supposedly disables EWS) had reverted back to 0x16. So it would seem then when turning the key off and back on the changes to the ECU were being lost. Digging a bit deeper into the OpenMS41 site I realized I needed to jump power to the program select pin on the Data Link (Diagnostic / X6002) connector (jump pin 14 and 18 ):

http://www.openms41.org/reading-writing

Luckily the cheap adaptor (Male X6002 to Female J1962) I bought on eBay allowed me to add a jumper wire rather easily once I opened it up:


So I flashed the ECU with the pins jumped, turned the key switch off and back on and the modified values stayed in the ECU. I guess when the program select pin is high it allows writing to the non-volatile part of the ECU memory.

2. Cranked the engine and it started right up... went to about 2000 RPM then died in a few seconds. When I held the throttle partially open it seemed to clean up and run OK. I'm betting that the buzzing noise I keep hearing indicates the ICV is bad. So now I'm going to replace that, also in the meantime going to try to rig up some kind of temporary muffler so I can run this thing for a few minutes without someone calling the cops... boy is it loud running the engine with open headers, haha :)

[sweet3]

Sweet! One big step forward. Sounds like a beast with only the headers haha.
Its normal to hear a small buzzing from the ICV. Not exactly sure what your sounds like though lol.

[MyE30]

2. Cranked the engine and it started right up... went to about 2000 RPM then died in a few seconds. When I held the throttle partially open it seemed to clean up and run OK. I'm betting that the buzzing noise I keep hearing indicates the ICV is bad. So now I'm going to replace that, also in the meantime going to try to rig up some kind of temporary muffler so I can run this thing for a few minutes without someone calling the cops... boy is it loud running the engine with open headers, haha :)

Sounds like you have a decent sized vacuum leak and that your IACV is working like it should (the buzz means it's working and is normal). You should make sure you don't have any vacuum leaks whatsoever before replacing the IACV.

[MyE30]

Oh yeah, OBDII > OBDI all day.

[BavarianGonzo]

Got a hold of another ICV, doesn't seem to make a difference. So MyE30 looks like you were correct, it's probably a vacuum leak. Searched most of the day today but couldn't find where the leak is. Right now I'm running the OBDII manifold that came with the engine... I just ordered the S50 manifold swap kit so I may just do that and continue troubleshooting from there. I really wish I could get it running with the OBDII manifold though.

One thing I did just now remember is that I'm missing one nut on the manifold studs... maybe this is the source of the leak? I would think the other 6 nuts would hold it tight enough though.

Maybe I have the fuel pressure regulator vaccum line plugged into the wrong port? There are two smaller ports on the underside of the OBDII manifold, one I plugged and the other I ran to the FPR. Maybe switching the two? Maybe I could just use my mityvac to pull vacuum on the FPR and see if that makes a difference?

Also for whatever reason (maybe because its super obvious for most people?) I have not been able to find a definitive labeled picture of what fuel line goes to what. Just to make sure I have them hooked up right, here is a picture of the lines.

I have them hooked up (starting from the bottom) vent line, feed to filter to front of rail, and the top is the return. Is that correct?

One more odd thing, my coolant temperature sensor is reading 120-140 degrees on the Torque app, is this an issue or is that just the bottom of the scale for that sensor?