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'74 D-JET 450SEL Not Running - Narrowed down to ECU

Started by chinny4290, 16 May 2016, 10:00 PM

chinny4290

Hi guys!

Boy, it's been quite a long since I've been here...but I had to put all my W116 efforts aside to take care of some life things, but I am BACK! No longer with a 280S to worry about, but a 1974 450SEL D-Jet!

So I just brought her home and my friend who is an ASE Certified Mechanic helped me trouble shoot everything. We found that everything was in great working order, voltage and OHMs included, at everything EXCEPT the ECU.

I'm thinking the ECU got shorted from the lovely and typical windshield drain hole since the ECU for US-Spec cars sits in the passenger footwell of the car, right where water leaks with that hole. The hole is fixed after the car was repainted down to the metal so the leak is a non-issue. But the ECU is still an issue.

My mechanic found that the ECU is receiving everything it needs to, but it does not send the necessary power pulse (or something along these lines) so basically, it's been narrowed down to the ECU.

I have another friend who's father is a retired Lockheed-Martin Electrical Engineer of many years and can fix pretty much anything with a circuit board. Is there any documentation on the ECUs itself that he can use if I call him to fix my ECU? It's way better I've read than buying a rebuilt unit and much cheaper, or trying to source a used one and gambling on that.

Look forward to hearing the responses guys! And attached is a pic of the car during transit :)
1975 W116 280S - SOLD
1994 W124 E320 Coupe - Gone

CURRENT - 1974 450SEL

ptashek

I've stumbled upon this once, when searching for old schematics related to our Benzes: http://members.rennlist.com/pbanders/ecu.htm
It's Porsche specific I think, but the Bosch unit used by MB was probably not much different.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

marku

If its any help I have a MB manual on the D-jet as a pdf if you want a copy send me a PM with an email. Also Bosch have re-issued their manual on the D-jet its printed from old microfiche so not a first rate image but is really worth having with a full schematic layout, wiring diagrams etc and troubleshooting. Last time I looked it was Euro29 on partbob.com.
450SE silver green/bamboo velour/green vinyl roof

chinny4290

Quote from: ptashek on 17 May 2016, 05:00 AM
I've stumbled upon this once, when searching for old schematics related to our Benzes: http://members.rennlist.com/pbanders/ecu.htm
It's Porsche specific I think, but the Bosch unit used by MB was probably not much different.

I looked into that but I also found another source here that says the Porsche units are totally different to the Merc units, especially the V8 ones. Which makes sense, fuel delivery for a V8 is much different for a flat four or six.


Quote from: marku on 17 May 2016, 01:51 PM
If its any help I have a MB manual on the D-jet as a pdf if you want a copy send me a PM with an email. Also Bosch have re-issued their manual on the D-jet its printed from old microfiche so not a first rate image but is really worth having with a full schematic layout, wiring diagrams etc and troubleshooting. Last time I looked it was Euro29 on partbob.com.

PM sent! :)

The PartBob.com site however is not responding, anywhere else I can look into that?
1975 W116 280S - SOLD
1994 W124 E320 Coupe - Gone

CURRENT - 1974 450SEL

marku

Seems OK unfortunately they are showing it only in German. They do have them in English but you have to keep looking. Got your PM manuals sent. Hope they are useful.

http://www.partbob.com/workshop-literature/d-jetronic/kundendienstanleitung-bosch-d-jetronic-in-mercedes-benz-r107-w107-w114-8-w116.html
450SE silver green/bamboo velour/green vinyl roof