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I know, not 928-related...but I was hoping to get the attention of some of the 928 gurus who may know the early MB R107 as well. So before it goes to OT:
I just picked up a nice '72 little bumper 450SL. When I bought it, it started up immediately but was running really rich...to the point of smoke and unburned fuel smell. The crankcase shows 1 qt. high on the dipstick and smells like gas. Owner warned me about the issue and told me that injectors had just been replaced by an MB specialist two years ago. It ran great for a few weeks and then sat for a month or two. When he started it up again, it ran rich. I have no idea what he may have done to it to try to get it running better. Original ignition/distributor which appears to be replaced recently. Today, it started up but started running crappy, then died. Tried to re-start to no avail. Fuel pump is coming on for a second or two at ignition. Seems to be fuel at the rails, but I can't confirm spark. I need to tow it home and would really like to get it running to get it on the trailer. I'm kind of solo at the point, so don't have a buddy to help with things like cranking the engine, checking for spark, etc. Anyone with experience with these cars that can lead me in the right direction?
It is CIS like the 928 but your 73 is D-Jet...also a common system from the era found in may European cars late 60s through mid 70s (914, volvo 1800s, etc.)
Inputs are barometric sensor, water temp, additional trigger points in the distributor (for injector timing) the computers are bulletproof and rarely fail. From memory the water temp sensor is a common problem and critical to mixture. there's a thermo time switch and a cold start valve that could be drowning it too. You probably have to start over from scratch depending on how many people messed with it already.
The haynes manual has a pretty good section on this D-jet system and the R107 forums are helpful.
Worked on many D jet systems over the years, Volvo's, VW's, 914's even Cosworth Vega's back in the 70's. Like every electrical system/electronic fuel injection system,start with power and grounds.Have found many poor grounds,usually a steel loop on the harness attached to an aluminum mounting surface that has gotten a fuzzy white coating on bolt the bolt and the machined surface.
Not sure I agree about the statement on the ECU's being "bulletproof" above, I seem to remember taking many of them to the locale TV repair shop and having the big transistor changed out to make the cars run, but maybe by now all the the ecu's have been rebuilt to a higher standard.
Nice looking 107. I've got a couple of 123's in the fleet myself,all M617 powered.
Worked on many D jet systems over the years, Volvo's, VW's, 914's even Cosworth Vega's back in the 70's. Like every electrical system/electronic fuel injection system,start with power and grounds.Have found many poor grounds,usually a steel loop on the harness attached to an aluminum mounting surface that has gotten a fuzzy white coating on bolt the bolt and the machined surface.
Not sure I agree about the statement on the ECU's being "bulletproof" above, I seem to remember taking many of them to the locale TV repair shop and having the big transistor changed out to make the cars run, but maybe by now all the the ecu's have been rebuilt to a higher standard.
Nice looking 107. I've got a couple of 123's in the fleet myself,all M617 powered.
Guess i got lucky with my D jet computers in my many Volvo 1800E cars ..although I was playing around with these in the mid eighties when they were not that old yet.
JP,
I had a silver/blue '73 R107 from 1980 through 2010. Solid like a tank for that era car. Engine was quite durable (front timing chain guides could fail leading to major problems). The cabin air control system also was prone to some failures. I had a great 'Italian immigrant' mechanic who did stuff I couldn't do on the car. He (and his heritage) focused on repairs/maintenance rather than throwing new parts at a problem. We actually became friends over the years. Sadly, he died about 2 years ago in his late 80's. Had closed his business about 2 years before that due to a heart attack. Miss him, and still miss the 450 SL. Still watch BAT listings to follow their values. Bring it to Frenzy, love to see it there.
Hope you enjoy the 'new caretaker' roll.
Thanks for the great info, links and sharing your pics & experiences! The tank-like build quality of these cars is obvious upon first glance. Pinging the 928 community was the way to go for sure. It amazes me the depth of mechanical/automotive knowledge and the wide range of experience that the average 928 owner has. Mods: thanks for not shooting this off into the OT abyss
I just picked up a nice '72 little bumper 450SL. When I bought it, it started up immediately but was running really rich...to the point of smoke and unburned fuel smell. The crankcase shows 1 qt. high on the dipstick and smells like gas. Owner warned me about the issue and told me that injectors had just been replaced by an MB specialist two years ago. It ran great for a few weeks and then sat for a month or two. When he started it up again, it ran rich.
Since new injectors initially fixed the problem, and then returned shortly thereafter, perhaps the fuel system has trash in it which is fouling the injectors.
Since new injectors initially fixed the problem, and then returned shortly thereafter, perhaps the fuel system has trash in it which is fouling the injectors.
That will definitely be my first step. Spark or not. That and replacing every questionable hose/line.
08-22-2023, 10:15 PM
Any MB R107 owners out there?
