Engine Swap No Spark.

[TheTripleNiple]

Posted before about DME matching problems in relation to an engine swap and found out the problem. I had the front of the vehicle jacked up after changing the transmission filter and fluid but couldn't fill appropriately and all the way full because it wasn't running. All the fluid was running to the back of the trans and triggering a low fluid state which caused the engine to not attempt to turn over. After the engine turned over I found out that it had no compression. I took it back to the salvage yard and they gave me another engine after all that work and it being their fault for not reading their painted "code" markings right. I now got an engine in it and turning over with good compression but no spark. I checked the signal wire "kind of" by putting a aluminum screw driver up to the fuel injectors and clearly hearing the click of them trigger to open up. I would like to check the power, ground and signal wire with a multi-meter at the harness and DME box but can't find which wires are which anywhere. Pictures or being informed of the color of which wires are which would be priceless right now. Oh and the details are needed also, the car is a 2003 325i E46 with a M54 engine. (original and replacement)

[randy72877]

Trans fluid will never stop the engine/starter from cranking. Check the fuses in the e-box. Do you have any codes? Why did you change your dme? If you are replacing a m54b25 with another m54b25 you should use the dme that came with the car so there is no issue with programming, ews, ect. Have you tried to use the original dme? Once an ews is linked to a dme, I don't think it can be made to work with another dme. You would need to use the dme, ews, keys and locks all from the donor vehicle. What do you have for diagnostics?

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[TheTripleNiple]

That's what I thought and its true about every other make than BMW as far as I know. OBD-II reader gave a transmission fluid low code and the only thing I changed was making sure the level was as full as I could get it without it running and leveling the car. The car turned over fine directly after that. I guarantee you that some certified BMW mechanic will verify that low transmission fluid code will electronically prevent the starter from cranking to prevent the transmission from burning up. I had the front of the car sky high and on centerblocks.(Top one solid of course) I did check the fuses and there were none blown. I'm using the DME and EWS that originally came with the car I'm trying to fix and drive. After it would crank It still had some other codes after I cleared them and I wrote them down but lost the paper. I got to loan-a-tool another OBD reader to further investigate. How do I find out if it's a B25 M54 after I put it in, also how do I find out if the original engine was a B25 after my father turned it in for scrap metal? Can I tell by the VIN or title?

[randy72877]

I have been a pro tech for over 20 years. I worked at a bmw dealer during the e46 era. I know for a fact that neither zf or gm auto transmissions had any type of fluid level sensor or switch. I have never seen that on any transmission in any car. The only thing related to the trans that can cause the engine not to crank is the range switch aka neutral safety switch. Obd readers won't read anything from the egs module. You probably got p0700 which just means that there is a fault in the egs (trans) module. B25 means it's a 2.5l and would be what was installed in 325, 525 z3/z4 2.5and x3 2.5 models of the time. M54 b30 is the 3.0l version installed in 330, 530, z3/z4 3.0 and x3/x5 3.0 I believe the engine ID is on the side of the block under the intake. I would Google "m54 engine identification" and see what you find.

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