Upgrading the K-Jetronic (CIS) fuel injection on my
1980 450slc Mercedes Benz
to a Megasquirt controlled electronic
fuel injection system.
Current Status:�
April 3, 2008 - Posted my latest MSQ file under MegaSquirt files.
July 20, 2007 - I recieved an RMA LC1 back from Innovate last weekend and it has been running flawlessly. This has allowed me to do some further tuning. I have changed from 2 squirts alternating to 4 squirts alternating as reccomended by Jim on the Megaboard. She now idles even smoother than before and she used to be very smooth. My poor tired firewall and home server have not been up to keeping up with the traffic this site is generating so I have opened a hosting account on GoDaddy. I am in the process of moving my site to this new hosted server.
June 23, 2007 - I have made several updates to the website over the past months and will continue adding to it. I have and RMA for my LC1 wideband O2 controller. As soon as I get a functioning controller back I will be able to further tweak my settings. I went to the junkyard last weekend and pulled several TPS's and a lot of air intake pieces from various cars. When I get an air intake built I will add a new page.
May 28, 2007 - I spent some time this weekend finishing the rewiring of my whole MegaSquirt installation. After I rewired everything the engine would turn over, run for a couple of seconds then die. I finally remembered that the stock fuel relay circuit requires a tach signal to keep the fuel pump running. Once I reconnected the tach signal to the fuel relay circuit she started running properly.
May 22, 2007 - I had my 450 running under the MegaSquirt fuel and spark for about a year but not running well. After conversing with fellow Mercedes enthusists in the BenzWorld vintage forum I found some new enthusiasm to finishing the tuning. After much reading on the MegaBoards and some trial and error I was able to get my Mercedes running very smoothly. I am very happy with the improved performance and driveability so I tore the whole fuel system apart again. I replaced some seals and gaskets during the reassembly. The biggest change I made was ripping out my "Proof of Concept" wiring and replacing it with a relayboard and straightening everything up. I am in the process of this rewiring currently.
I have owned my 450slc for about 12 years now and I am very fond of this car. The thing that impresses me the most about this car is the build quality. I love that my 27 year old car has two big and heavy doors that have never drooped.
There are some engineering issues with the 107 body cars that have always bothered me. A few that imeadiately come to mind are the air conditioneer servo, the cruise control and the mechanical CIS fuel injection system. After years of the performance of my 78K mile car continually declining despite replacing nearly every fuel injection component short of the ~$1000 fuel distributor. I finally decided there had to be a better way.
I looked at several options and a carburator seemed to be the obvious choice. I have never had a carburator give me the trouble the CIS injection system has. After several hours of studying the Mercedes shop manual and poking around the engine I decided a carburator would not be feasable. I had been following a website for many years about a group of auto enthusiats who were building their own fuel injection computer. I remember reading about noisy signals and burnt out components and somewhat unreliable performance. Then in 2004 I revisited that website and found these same guys were on version 2 of the processor and version 3 of their circuit board. The website was of course "MegaSquirt". As it turned out these auto enthusiasts had a lot more follow thru than I have ever had and have made a top of the line product out of their tinkering. I figured since they had done all of the work I might as well reap the benefits.