300E 5-Speed Swap ECU question
 

We are looking to swap a 5speed into a 1990 300E using a 1986 300E donor car. The '86 was in a junkyard so we do not have the car sitting here, but got the driveshaft, crossmember, pedals, flywheel, trans, etc.

I have done manual swaps on benzes before but all diesels.

Can we simply replace the auto with the manual setup and will it run fine? The '86 looked to have different computers than the '90 does but I did not know if you need the manual ecu to run the manual trans.

I realize the 722.4 is mechanical, On some GM cars (used to mess around with Fieros) if you put a manual gearbox behind some motors they would stall unless you changed the PROM in OBD1 or reflashed the OBD2 ecus with the manual maps. I agree applying GM know-how to a Benz is frequently dangerous, but I would rather ask now than have a car that stalls every time we dip the clutch.

It's possible you might have issues. Do a search for upshft delay on the M103. I know my 91 has it and the 90 may as well.

That's vacuum based I thought. Once I remove the vacuum lines related to the 722 I don't see how that could affect the car.

DP:

To the best of my knowledge the K-jet systems do not receive any feedback information from the transmissions, either automatic or manual. The shift delays, both up and down, used with the 722.3 and.4 transmissions are purely mechanical, and a function of manifold pressure. Your change from an auto box to manual, should not have any effect on the engine controls.

Your experience with Fieros involved electronic injection and spark control, and yes, GM did use transmission feedback in those systems.

Thanks Frank. We will go ahead and do the swap soon as we gather new hydraulics, clutch kit etc.

The only thing I can think of that might be the same on a M103 is that on my M102 inlet manifold there's a vacuum line going to the transmission that needs to be plugged.

http://www.benzworld.org/forums/atta...-manifold1.jpg

http://www.benzworld.org/forums/atta...1&d=1406550361

The W201 M103 fuel injection chapter is easy to reach here

http://www.startekinfo.com/StarTek/outside/11832/Resources/201Create/PDF/50006.pdf

Make sure the 86 has the correct timing windows on the flywheel that your 90 requires.