Ok, I'm kinda ticked at my girlfriend's '89 240DL (auto trans). After her dad spendt a huge pile of money this summer getting a new ECU for the thing and other stuff, it now fails again. Now, it works fine most of the time, but every now and again (especially when it's wet), the engine lugs really hard and loses speed down to about 20mph (no good on the highway). No matter how hard the gas is pushed it just lugs down, but eventually regains itself and works fine again. Odd? I think so. The diagnostics spits out 3-1-1 (speed signal missing) and 2-1-2 (02 sensor not working). would these things not working cause this major of a problem? In all my experience on 240's, I still don't know where the vehicle speed signal comes from. Could the "new" ECU be bad? I'm confused on this one...I guess it'll be fun with Bentley and Voltmeter this weekend if I have time...if anyone has suggestions, it would help a lot. thanks!

Nate Gundy
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'86 240DL, M46, K cam, 25/21mm sways

Put a new speed sensor in it and a new O2 probe. www.fcpgroton.com, should be in the $150 to $200 range for both and you can install them. Bentley has good directions for both.

Get your Bentley and look in the section of the ignition system (page 280-2) and see Fig 3. It shows the inductive speed pick-up. It is located on top of the tranny,just in front of the firewall. Replace it.
Also replace your O2 sensor..
Call FCPGroton for a good price on either or go to your local dealer for fast service.
No problema.
el Raidman