SL/R107: 1989 560SL - need expertise
Thread Starter
Junior Member
Joined: Oct 2018
Posts: 15
Likes: 8
1989 560SL
1989 560SL - need expertise
Just purchased an ‘89 560SL with 54K mileage at the end of Oct. Garaged for the last 10 years and driven about 50 miles per year. A complete list of recent service items listed below. Car runs great with one exception ... when I turn key for a cold start it cranks for 3-4 seconds before it starts, recently drove for about an hour then stopped for about 20-25 minutes and when I went to start it the same thing happened. However, if I drive the car and get back into within 5-10 minutes it seems like the car starts immediately. Any ideas from anyone that has had the same issue - electrical, fuel accumulator, air leak, fuel injectors? Note: I’ve already run Bg44K through one full tank of gas and planning a 2nd tank once it arrives in the mail.
- E-Service - replaced wipers, plugs, fluids, filters for PS, oil, air, fuel (Oct 2018)
- Genuine MB rubber antennae base replacement (Oct 2018)
- Genuine MB steering coupler replacement (Oct 2018)
- Genuine MB shifter bushings replacement (Oct 2018)
- Genuine MB visor clip replacements (Oct 2018)
- Genuine MB hood liner replacement (Oct 2018)
- Genuine MB hood seal - section under hood near windshield (Oct 2018)
- Repaired electrical short impacting fuse #12 (Oct 2018)
- Transmission service (Oct 2018)
- Radiator coolant flush (Oct 2018)
- Replaced hard top seals (Oct 2018)
- Replaced 5 engine belts (Oct 2018)
- Replaced emission filter (Oct 2018)
- Replaced 2 outer tire rod ends (Sept 2018)
- Replaced 2 inner tire rod ends (Sept 2018j
- Replaced center link (Sept 2018)
- Replaced HVAC control unit (Sept 2018)
- Replaced 4 HVAC control bulbs (Sept 2018)
- Replaced brake master cylinder, and pressure bleed brake system (April 2018)
- Replaced right front brake caliper which locked up after driving (April 2018)
- New battery (Jan 2017)
- New air intake hose (Jan 2017)
Newbie
Joined: Oct 2018
Posts: 10
Likes: 3
From: Mequon wisconsin
1986 560sl
My '86 with 86k miles does the exact same thing. I have new injectors and had my Indy shop replace all vacuum hoses and rubber parts. I am on my 3rd tank of injector cleaner. I've been doing a lot off reading on line regarding KE Jetronic. My next steps I want to do myself. I plan to
1) take fuel pressure- system, and control. You can rent a pressure kit from local parts shops but it looks like I will need to go to hardware store for some proper fittings.
2) check the holding pressure after the engine shuts off. It should drop to 3 bar and the hold it. If the pressure drops I think it means a new accumulator next to the gas pumps.
3) get the cycle duty readings using a volmeter and doing the math conversion. There is more info on the net with better instructions. I just don't have the link at the moment. I have no idea what these readings mean and hope to get some analysis here.
Look forward to seeing what you do and your results. I will add to your thread whatever I might find.
1) take fuel pressure- system, and control. You can rent a pressure kit from local parts shops but it looks like I will need to go to hardware store for some proper fittings.
2) check the holding pressure after the engine shuts off. It should drop to 3 bar and the hold it. If the pressure drops I think it means a new accumulator next to the gas pumps.
3) get the cycle duty readings using a volmeter and doing the math conversion. There is more info on the net with better instructions. I just don't have the link at the moment. I have no idea what these readings mean and hope to get some analysis here.
Look forward to seeing what you do and your results. I will add to your thread whatever I might find.
Member
Joined: Feb 2013
Posts: 207
Likes: 37
From: Beaverdam, VA
W123 300CD, R107 560SL, W211 E320
The job of the fuel accumulator is to maintain pressure in the fuel system after shutdown for an easier restart. Sounds like that may be your problem.
The 560SL loves to be driven. You are not doing it any favors by only driving 50 miles/year. I used to put about 10k/year on mine until my wife totalled it and it was as reliable as a Chevy. If you really like the car, drive it more. You won't hurt it. If it is an "investment" sell it now. There are so many of these cars around, it will not appreciate significantly.
The 560SL loves to be driven. You are not doing it any favors by only driving 50 miles/year. I used to put about 10k/year on mine until my wife totalled it and it was as reliable as a Chevy. If you really like the car, drive it more. You won't hurt it. If it is an "investment" sell it now. There are so many of these cars around, it will not appreciate significantly.
Thread Starter
Junior Member
Joined: Oct 2018
Posts: 15
Likes: 8
1989 560SL
Thanks Rocky. Previous owner only drove it 50 miles / year as I’ve already put 500 miles on it in 4 weeks and the hard top hasn’t been removed yet bc I’m having a new soft top installed. It’s my new daily driver so it will get a good consistent work out on a regular basis. Appreciate the advice on fuel accumulator.
Last edited by McLovinMyBenz; Dec 7, 2018 at 12:25 PM.
Thread Starter
Junior Member
Joined: Oct 2018
Posts: 15
Likes: 8
1989 560SL
My '86 with 86k miles does the exact same thing. I have new injectors and had my Indy shop replace all vacuum hoses and rubber parts. I am on my 3rd tank of injector cleaner. I've been doing a lot off reading on line regarding KE Jetronic. My next steps I want to do myself. I plan to
1) take fuel pressure- system, and control. You can rent a pressure kit from local parts shops but it looks like I will need to go to hardware store for some proper fittings.
2) check the holding pressure after the engine shuts off. It should drop to 3 bar and the hold it. If the pressure drops I think it means a new accumulator next to the gas pumps.
3) get the cycle duty readings using a volmeter and doing the math conversion. There is more info on the net with better instructions. I just don't have the link at the moment. I have no idea what these readings mean and hope to get some analysis here.
Look forward to seeing what you do and your results. I will add to your thread whatever I might find.
1) take fuel pressure- system, and control. You can rent a pressure kit from local parts shops but it looks like I will need to go to hardware store for some proper fittings.
2) check the holding pressure after the engine shuts off. It should drop to 3 bar and the hold it. If the pressure drops I think it means a new accumulator next to the gas pumps.
3) get the cycle duty readings using a volmeter and doing the math conversion. There is more info on the net with better instructions. I just don't have the link at the moment. I have no idea what these readings mean and hope to get some analysis here.
Look forward to seeing what you do and your results. I will add to your thread whatever I might find.
Had a fuel pressure diagnostic test run ($390); mechanic replaced fuel accumulator, electro hydraulic actuator. Picked up the car and it started right up but then stalled while driving after 1.5 miles on way home and had to have it towed back to mechanic. Mechanic ran another test and replaced the fuel pump relay and overload protection relay. Car now runs like new ... starts up right away, it had been idling at about 1100 in park and is now running around 700. Pretty sure normal is around 500-600 but will deal with that another day.
Newbie
Joined: Oct 2018
Posts: 10
Likes: 3
From: Mequon wisconsin
1986 560sl
Hey friend sounds like success! I am moving a lot slower than you are. Currently I'm checking all the inputs and outputs. Looks like my coolant temp sensors - the ones next to the cold start valve- are working. Bit I need a multi meter with milivolts to check the oxygen sensor, EHV and ICV. Maybe tomorrow. My EHV just started to leak fuel, a new issue. Replaced the o rings but it appears the body of the valve has become pourus.i have until May to get it back up to speed. My car has never seen a Wisconsin winter.
