5.6L engine transplant into 380SL - Mercedes-Benz Forum

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post #1 of 3 (permalink) Old 09-02-2013, 08:32 PM Thread Starter
BenzWorld Junior Member
Date registered: Jul 2010
Vehicle: 1987 300SDL
Location: Greenville, SC
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5.6L engine transplant into 380SL

I had a local independent M.B. shop install a 5.6 liter engine in my 380SL because my 3.8 engine was toast. It runs strong to about 5K RPM WOT then cuts out completely (as in fuel starvation) until throttle pressure is reduced. Due to difficulty interfacing the 5.6L engine harness to the 380 chassis, I went with the 380 fuel system. No additional fuel pump was added. It has been years now with no resolution. I do not care if it does not run above 5K RPM if it would max out there and not cut out. Once had a smoking problem from cat converter when idling with injector cleaner in fuel. Have not changed converter. Is that number 1 thing to try or is my problem characteristic of 380 fuel system feeding 5.6L engine? Would a second pump be in order? If so where mounted?
Thank you
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post #2 of 3 (permalink) Old 09-02-2013, 09:00 PM
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Date registered: Sep 2006
Vehicle: 1989 560SEC AMG Euro / 1997 S500 / 1991 500 SL Euro / 1991 500 SL Japan
Location: Vancouver, BC, Canada
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Did you change the fuel pump relay when you did the swap?

Someone please correct me if I am wrong but I believe the 500/560's used a FPR that cut out around 6000/rpm.

I'd start diagnosing it from there if it has not been done.

- Steve
1989 560SEC AMG Euro / 1990 300SE Euro / 1991 500SL Japan / 1997 S500 USA
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post #3 of 3 (permalink) Old 09-02-2013, 11:01 PM
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Date registered: Mar 2013
Vehicle: 2008 ML320CDI 4Matic, 161K miles; 1983 380SL (die Rostlaube), 238K miles
Location: Fairmont, Minnesota, USA
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Get thee over to the R107 forum. There's a guy there who did that exact swap.
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