I just brought home my grandmother's '89 560sel this weekend, and I have a few questions. It has been sitting up for about 1 1/2 years, and has 120k miles on it. Firts of all, it's very hard to start cold. Starts fine after it warms up. Second, the check engine light stays on all the time. I checked for loose vacuum lines, etc, but I don't know what faults would make the light come on; I don't have a tech manual for it yet. Third, the oil pressure guage pegs out when it's running. Could the sending unit be plugged up, and where is it. I just flushed the engine and changed the filter/oil, but it didn't help. Other than that, it's a super car. I was surprised that everything except for one of the headlamp wipers works (haven't looked at it yet). I just have to figure out a way to get my old lady out of it long enough for me to be able to drive it. Thanks for any input,
Chris

The car has been idle for an extended period of time, so hard cold starting wouldn't be unusual. Others more versed in the ways of the 560 will likely have better answers than mine, but here's my 2 cents for what it's worth.

- Has the gas tank been drained flushed? Crud in the tank?
- How about the fuel filter? Might not hurt to change it.
- Varnish/gumming deposits have likely formed through the fuel system. You'll likely receive all sorts of ideas here about using some sort of fuel system cleaner. It might help.
- How old is the battery? Was it replaced?
- The oil pressure reads at the max level on these cars once your RPM gets up to about 1500 or so. This is normal.

I think it would be difficult to list everything that could need changing, but for starters, I'd change all fluids/filters. The cyl. head may have dried out, in which case your may experience increased oil usage thru guides/seals.

Good luck with your 560. These are very nice cars.

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

Okay, I'm only 30, but I guess I'm still in the stone age, because I don't know squat about fuel injection systems outside of the basics, much less computer controlled ones. The last car I really had to work on was my '71 MGB, and I sold it 5 years ago . From the information I've gathered about it there is a temperature sensor (somewhere) that tells the computer that the engine is cold, and it operates a valve or something to help the engine start and run until it gets warm enough. From another post I've read, if there is something wrong with the sensor, it will make the engine light come on. I'm kind of leaning this direction because it acts the same as trying to start a carbureted car when you forget to pull the choke, but it runs fine and starts right back up when it's warm. The question is, where is the sensor(s) and the valve or whatever it is that is supposed to help it start cold, and how do I check it? BTW, it has a new battery, and I put a bottle of gas treatment and injector cleaner in for varnish and the possibility of water in the gas. Thanks,
Chris

The cold start valve should look like a ninth injector, on my car it is located at the left front of the intake manifold (it might have been relocated in later models). As far as fuel treatment goes try to find Red Line Complete Fuel System Cleaner. Not sure where you'd find it in Jackson, I get it at Pep Boys. You might be able to get it here at PartsShop.

Start with a complete bottle for initial dosage, then follow the recommended amounts on following tanks. This stuff works good. Costs about $5/bottle.

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Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Another cause of cold start problems are the fuel pump check valves. These are back by the fuel filters. You should change your filters now anyway, so do the valves too. They keep fuel pressure in the lines when the pump is off. If they don't work, you have to pump up pressure before the injectors get fuel. After you get the car started, is it good for the day?

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VR
1967 250SL