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Engine Swapping and what to look out for

Doing an engine swap on an older BMW but it won’t start? Here’s what to look out for.

Older BMW models have a certain je ne sais quoi about them, a quality that makes us love them a lot, even though their performance might not be up to par with what we’re used to nowadays. We can easily include the BMW E30 3 Series in this mix, or the E34 5 Series. These cars have a timeless design and well-engineered chassis’.

And while we do love these cars, their engines will feel outdated and underpowered, compared to the turbocharged monsters we’ve gotten used to over recent years. That’s why you see a lot of engine swap projects being done today, where older models get younger beating hearts under the hood, for a great mix of looks and power.

However, if you want to go down that route, you might hit a snag or two. One of the issues you could come across might be starting the newly installed engine in the first place. If you can’t start it, you can look for a number of issues, most often than not a DME unlock being necessary to solve problems related to the EWS system.

The EWS works like an anti-theft system on your car. It basically decrypts a signal sent by the transponder located inside your key fob to the DME. If the data package sent is correct, the EWS system enables the starter by way of a relay installed in the DME and, additionally, sends a coded start enable signal via a data link to the DME. If errors occur during communication between the EWS control unit and the keys, your car won’t start. Therefore, you’ll need to unlock or remove the EWS system altogether.

Going to a dealer won’t be an option in this case, as most of them will be reluctant towards any sort of engine swap job. Fret not though, because there are specialists out there who can do the job for a few hundred dollars. All you need to do is send the DME over to them, have its software upgraded and install it back in your car. All done! 

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