89 300E, tough starting....help please

This past may i gave my sister my 300E with about 119K on it. In the past year I replaced and serviced many parts. The car runs great ohter than having a real hard time starting. It takes about 3 or 4 times and holding the pedal down all the way. SOmeone told me it could be the fuel pressure regulator.....? Anyone else have any idea what it could be? Thanks, Charlie, Monmouth County NJ

IMHO the fuel pressure is probably OK because the problem only occurs at cold starts.
Fuel injected engines have a "cold start system" that injects additional fuel into the engine for a very short time during cold starts - five to fifteen seconds to help get them started and for initial warm-up.
Basically, there's an engine temperature sensor: ON below a certain temperature and OFF above it. A relay that's ON longer as the temperature is lower. And an electric cold start valve: ON injects fuel, OFF cuts off the fuel.
One of these isn't doing what it should be.

i dont think any smoke, when i mean hard starting, i mean realy really hard starting....you turn that key and you have to hold it over for a long time and keep on stomping down on the pedal- thanks tg and00 for your help so far

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Fuel pressure regulator is an excellent guess. Classic symptoms for that defect.
Marty

Hello from Norway
Does the engine smoke black "when" it starts after several try ?
Eivin
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(oo=oo) wrote:
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Eivin,
Glad you mentioned this.I have 91 560SEC that takes 2 to 3 long cranks to start and there is a black smoke when it starts up. No problem starting cold though. Have not figured the cause for this yet.
Saeef

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Well, black smoke is usually unburned fuel, so that's probably just a secondary symptom of whatever's making your car hard to start when hot, rather than a separate problem.
I had some hot-starting problems on my 250C as well, but narrowed it down to the fact that I was using a new electronic distributor with the original stock coil. After installing an MSD coil and ignition control box, and widening the gaps on the spark plugs, the problem went away.
Is everything stock in your engine? If your timing is set correctly, and you have good engine vacuum, I'd have a tech look at your ignition system. You coil may be starting to go, and becoming weaker when hot.

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This is most likely a fuel injector that is leaking into the cylinder. That causes fuel to build up there, which creates a black puff of smoke when starting...
A guess of course, only a guess...

Try some fuel injection cleaning (add one botle when filling up) You may have some "dirty" injectors(dripping over the night, filling up sylinders"
Eivin
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What about white smoke, coming out from the engine compartment and tailpipe ONLY after the car sits for a couple days without being started? It takes about 10 minutes to get it started, then it misses for about 20 mmiles of driving, then it runs great?

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It comes from the engine compartment AND the tailpipe?
This could be bad. Perhaps a leaking head gasket that is losing coolant both internally and externally. Keep an eye on coolant level and also check the oil and coolant for any strange appearance.
Good Luck, Marty

I check all that, and it has been fine. The smoke isn't like the "steam" you get from burning antifreeze/water. The smoke from the engine compartment appears to be coming out of the air cleaner.