E320 - Delayed hot start fixed! Here's how.

I'm posting this tome "for the archives," hopefully it will help an owner to fix his or her car.
The engine is a '97 24 valve straight six, #104.995.
I've owned this car since new. After about 15K miles I noticed that some starts took longer but I couldn't relate those instances to anything. At 18K miles the dealer checked the fuel system pressure and found it to be OK, they also checked the crank position sensor; it was OK. No other ideas were offered and the new car warranty expired.
Time passed and the problem ripened. Cold starts were instantaneous, but with a strong fuel odor from the exhaust. Hot starts were fine if the engine was restarted within, say 10 minutes, but delayed thereafter - crank crank crank - until the throttle was opened the engine then roared to life. The exhaust then had a strong fuel odor. It was as if a carburated engine were "flooded".
The engine ran well otherwise, had lots of power and good fuel economy; it passed all California's biannual SMOG inspections.
At 30K miles I installed new spark plugs and found a strong fuel odor in the engine's air intake and #6 spark plug wet with fuel. I added fuel system and injector cleaner to the tank and the problem seemed to improve, but not for long.
Since I know more about carburated engines than fuel injected ones I researched gas fuel injectors and learned that they can be professionally cleaned ultrasonically of the fuel deposits that build up over time but that a leaking injector due to a bit of internal rust or corrosion probably needs to be replaced. There was also the actual "how to" aspect of removing the injectors and whether to remove all six for cleaning and testing or to try to identify the probable leaker.
Rather than pull all the injectors for testing I parked the car for a few days (to leak) and removed all the spark plugs. Sure enough, #6 was again wet with fuel so I was assured that #6 injector was the culprit.
A "rail" (pipe) supplies (approx.) 45 psi fuel pressure to the injectors; the connections are sealed by rubber "O" rings on the injectors. So to remove the injectors one needs to relieve the fuel pressure and drain the fuel rail. Some Volvo owners pull the fuel pump relay and run the engine to reduce the pressure and consume fuel in the rail. Others just put a rag over it to contain the spray and catch as much fuel as possible in a can. Neither prospect attracted me.
I had the local M-B dealer estimate the job of replacing only #6 fuel injector - not cheap but specific, no "let's try this and if it doesn't work we can do that" guessing game. Now it's fixed - 2 hours labor and a new Bosch injector.
What a difference! Just like a new car again.
Thomas G. Lambach '97 E320 @ 38K miles
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That's great! Only 38K miles after nearly 8 years?
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37,700 yesterday, always garaged too!
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Somebody who drives even less than I do... I have almost 21 000 miles since May 01...
Mind you, my 'chauffeurs' on Airbus and Boeing vehicles put in a little more mileage...
:-) DAS
--
For direct contact replace nospam with schmetterling
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So Thomas, is this the car you are going to get rid of if you buy a new one?
I am interested ;~)
Marty
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Yes this will be sold next year, after the new V-6 diesel E Class is available in CA (or not), the new S Class is available and the new Lexus LS is available.
Meanwhile, the '97 is Smoke Silver / Parchment, no sunroof, non-smoker's car, now at 37,700 miles, always garaged. I'm the first owner. The car is located in SF Bay Area.
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No sunroof? I can't recall a MB sold lately without sunroof!
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The great part of owning a E Class is that it can be ordered without a sunroof, not so with the S Klass.
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That's great you narrowed it down to one fuel injector. We just replaced 8 of them in a 1985 Corvette to fix the same problem. It did seem to fix the problem (it was an all afternoon job, so I am glad :) )

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