Thank you for you respone. This was the second tech that I have been to. The first one charged me $300 to replace a distributor cap and rotor and suggested that I confirm that all the fundamentals were working first before going forward.

I was recommended to go to this second tech who had 15 years of experience with MBs and Audis. My 300E was imported from overseas and has only 31,000 miles and was not driven very much at all. The mechanic identified that there was a pressure leak in the fuel system which would account for the difficulty in the cold starts in the morning. He indicated that the air had to be displaced in the system before the gas could reach the engine which would account for the difficulty starting. He also removed one of the injectors and confirmed that the spay pattern of the injector was very irregular and was caused by residue in the engine and the injectors. This was preventing the injectors from closing properly and allowing a leak of pressure.

Are these accurate conclusions. From my limited knowledge, it would seem to be reasonably accurate based on the starting issues I am encountering..

ok, as i said, pinpoint the pressure loss. its done by pulling all inj and seeing if they drip. but i'm starting to think you need to put some miles on this car with some cleaner in the tank.
also has this car bit set up as to the on/off ratio and such? c.o. been adjusted? get out and drive it.

george

Dear Keen,

Hard starts are difficult to diagnose. A lot of components in these cars contribute to the hard starts and rough idle. I know because I've been through it (during the first year when I purchased the car and most recently).

You'll learn a lot from these forum and the best part is that it gives you a better perspective of what a tech is trying to do (repair) in your car.

One question though, is the car for keeps? I'm asking because the repairs can be frustrating sometimes not to mention expensive This, especially when you don't have the likes of the stevebfl, benzmac, m.b. doc, nearby who are great at diagnosing problems related to these cars. Parts can be thrown at the car without curing your basic issue.

Based on my experience (exclude those you've already tested), here is the the list of those that may be related to your problem:

1. Caps, rotors, wires, plugs, coil
2. Air slide valve, aka, Idle control valve, Idle air control valve, idle control unit
3. OVP (the fuse may be good but it can fail internally)
4. dirty injectors
5. dirty fuel distributors
6. failing fuel regulator
7. clogged fuel filter
8. failing fuel pump and pump relay
9. ECU, aka, Electornic control unit, electronic control module, control box (do a search)
10. temp sensor
11. cold start valve
12. top engine rebuilt

I'm not a mechanic and I don't know how to test parts. At this point I cannot tell you a particular solution. I think you'll just have to go at it one part at a time. You'll need to change some, if not all, anyway given the age of the car. But I suggest that you find a good and reliable tech as this will be cheaper for you in the long run.

It seems that it is common suggestion that I get out and drive this car which I plan to do this week out of town on the highway. With regards to the Co adjustment, I live in Canada where mandatory emissions tests are required to be taken at registered facilities.

The car upon its first attempt failed the Nitrogen Oxides (No) component of the test. It was suggested that the car had residue in the engine which needed to be cleaned, which was done. During the cleaning of the engine with a Motorvac machine, my mechanic noted that it was running lean and so made adjustments to make it run a little richer. The car was then brought back to the testing faciltiy and ret-tested at which point it passed the "No" test with flying colours but failed the Hydrocarbons and Carbon monoxide components of the test. The testing facility quickly suggested replacing the O2 sensor.

I was uncertain whether this was the solution and conferred with my mechanic, who noted that the car was running too rich and that the Co had to be reset.

I am still attempting to resolve may hard start problem and this emissions test issue. If anyone is able to shed any additional insight on these areas, please accept my gratitude in advance.

Has your Water temp sensor been tested yet?
I am having a similar emmissions problem: http://www.peachparts.com/shopforum/showthread.php?t=115412
I will let you know if I cure it.
Marty

Baffled
 

I have just returned from my mechanic with much lighter pockets and the same hard start issue. As of this time, we have confirmed that it is not the following items listed below by replacing each component with a spare unit or acutally testing the resistance.

EHA
OVP
Computer Ignition Module
Fuel Distributor
Air Flow Meter
Temp control Sensor
Cold Start Valve
Check Valve
Plug wires
Fuel Pressure Test (different results than the first test - no pressure loss)

Replaced coil, dist. cap, rotor, plugs

The mechanic has indicated that the Catalytic converter may be plugged which has caused the car to fail the emissions test. He used a device which detected the temp of the converter during operation. It was determined that the temp at the front of the converter was higher than the back.

He has also suggested that since the Converter was not functioning properly and allowing unburned gas back into the combustion chamber, it would effect the emission test and possibly the hard starts on the vehicle.

He disconnted the cat pipe at the exhaust header and allowed the engine to cool down then started the engine. He indicated that it did start easier and concluded that the converter should be replaced.

Would any seasoned mechanic be able to shed any light on my dilemma. I am extremely frustrated at the lack of results.

Thank you in advance.

I'm betting that you're the gentleman that I spent some time talking to at Charlie's shop while they were tracing the hard-start gremlins in your 124. My fingers are crossed for you that it is something less expensive than a catalytic converter. If it was on my 202, I'd be certain that it was the converter because that sounds like the most expensive thing it could possibly be. I just don't have the best luck that way.

It was good to meet you. I hope this gets figured out quickly.

Jonathan

Had the same problem with my 260E, but even more weird; that is, in freezing cold (-16 degrees Celsius) it started at the first turn of the key and ran well, but a few days after, when the weather had warmed up, it refused to start.

After a half mile of towing (could not risk to damage the starter motor by cranking endlessly) it started, but huffed, puffed, vibrated like a Diesel. When it finally had warmed up, it ran well (but with weak acceleration).

The story has repeated for two more times(long cranking, hard start), but not in consecutive days. After that, the car went back to normal by itself, without any intervention, and now runs well & safe, but it still doesn't accelerate as quick as it should.

Suspected it had to have been either the injectors(never cleaned) or the cold start injector valve, since the gasoline here is always dirty(more accurate would be to say it's "dirt with some gasoline in it" :( )

~Nautilus

Resolution to difficult cold starts
 

Well after much time, effort and expense, I have been able to resolve the hard start issues I was experiencing. As my previous postings have indicated the car has been examined very closely and the culprit was the ECU. This accounted for failed emissions tests (failed the Nox ) as well as extreme difficulty starting.

I hope this will be of assistance to anyone that may be encountering the same issues. Please feel free to contact me if I may be of any assistance.

Thank you to all those who reviewed the posts and also those who shared their thoughts and time.

I'm sure that is not cheap!!

recently bought a used one at about US$260.00. i think a new one here would cost about US$1,400.00.